How to Adjust SEM Bids for Seasonal Trends

Joseph Perry
1 day ago
14 min read

Adjusting SEM bids for seasonal trends is essential to maximize ad performance and manage costs effectively. Search demand fluctuates throughout the year, driven by events like Black Friday, tax season, or back-to-school shopping. Without adjusting your bids, you risk losing visibility during high-demand periods or overspending during slower times. Here’s a quick breakdown:

Why Seasonal Trends Matter: Search volume and competition surge during events like holidays, leading to higher CPCs but often better conversion rates.
Key Benefits of Seasonal Adjustments:
- Boost visibility and conversions during peak demand.
- Avoid wasting budget during low-intent periods.
- Improve overall return on ad spend (ROAS).
Steps to Optimize Seasonal Bids:
1. Analyze Historical Data: Review past performance to identify patterns and key seasonal events.
2. Segment Campaigns: Group keywords or campaigns by their sensitivity to seasonal trends.
3. Adjust Bids:
  - Use manual adjustments for precise control.
  - Leverage Smart Bidding for real-time optimizations.
  - Set seasonal adjustment windows for short-term events.
4. Monitor & Refine: Track metrics daily and run A/B tests to improve results.

When and How to Set Up Seasonality Bid Adjustments in Google Ads

How to Analyze Seasonal Demand Patterns

To fine-tune your bidding strategies, you first need to grasp how demand shifts throughout the year. This means digging into historical data to uncover trends, pinpointing events that influence those trends, and identifying which parts of your campaigns are most impacted. Here’s how you can break it down.

Review Past Campaign Performance

Start by pulling 12 to 24 months of data from tools like Google Ads and Google Analytics. This timeline lets you spot year-over-year trends while filtering out one-off spikes caused by promotions or technical issues [1]. Focus on key metrics like impressions, clicks, click-through rate (CTR), average cost per click (CPC), conversions, conversion rate, and return on ad spend (ROAS). Break these down further by campaign, ad group, keyword, device, and location within the U.S.

Visualize your metrics weekly or monthly to identify recurring peaks and dips during the same calendar periods each year. For instance, an ecommerce brand might see CPC and impressions climb in early November, with conversion rates and ROAS peaking around Thanksgiving and Black Friday. To confirm a seasonal trend, compare the same timeframe across multiple years. A consistent 20%-30% change in a key metric during the same period is a solid indicator of seasonality.

To validate your findings, cross-check your ad performance with other data sources like website analytics, sales records, and CRM data. If your internal numbers show higher close rates or bigger average order values during specific months, it reinforces your campaign insights. Don’t forget to account for anomalies like one-time promotions, tracking changes, or budget constraints. And for industries with delayed conversions, factor in your typical conversion window when defining seasonal periods.

These insights help you zero in on the key seasonal events that matter most to your business.

Identify Key Seasonal Events

Once you’ve charted your performance data, overlay it with a U.S. retail and services calendar to see which events align with your observed trends. Major periods to watch include Black Friday, Cyber Monday, Christmas, New Year’s promotions, Valentine’s Day, tax season (January-April), Memorial Day, back-to-school (August-September), and the Fourth of July. Compare your campaign metrics during these events to the surrounding weeks. If impressions, CPC, and conversions spike significantly, you’ve likely found a key seasonal driver.

Keep in mind that not every business follows the same seasonal patterns. A travel agency might thrive during summer vacation planning, while a B2B company could see end-of-quarter surges as clients close fiscal deals. Also, don’t overlook “micro-seasons,” like weekend flash sales or bi-weekly payday spikes, which may justify short-term bid adjustments.

After pinpointing your key events, assign an estimated impact score to each based on historical conversion and ROAS increases. Group these events into tiers:

Major peaks: High-impact periods like Black Friday or Christmas.
Moderate peaks: Events such as back-to-school or summer sales.
Niche events: Industry-specific occasions or local holidays.

This prioritization helps you focus your resources - like aggressive bidding, creative updates, and budget boosts - on the periods most likely to yield strong returns.

Use these clearly defined events to guide your bid adjustments in campaigns that are most sensitive to seasonal demand.

Segment Campaigns by Seasonal Sensitivity

Not all campaigns or keywords react the same way to seasonal trends. Some see dramatic changes, while others remain steady year-round. By segmenting your campaigns based on their sensitivity to seasonal shifts, you can adjust bids more effectively across your portfolio.

Calculate the seasonal lift for each campaign or keyword by comparing performance metrics (like conversion rate or ROAS) during peak periods to a neutral baseline, such as the average performance in surrounding months. For example, a keyword like “Christmas gifts under $50” might see a sharp increase in November and December, while evergreen terms like “emergency plumber near me” perform consistently year-round.

Divide your campaigns into three categories:

High sensitivity: Campaigns or keywords with a 40% or greater increase in conversions or ROAS during a seasonal period. These deserve aggressive bid and budget adjustments.
Moderate sensitivity: Those with a 15%-40% uplift, which benefit from moderate bid increases.
Low sensitivity: Campaigns with less than a 15% change or flat performance, where steady bids are usually best.

Label these segments in platforms like Google Ads (e.g., “Seasonal_High,” “Seasonal_Moderate,” “Seasonal_Low”) and save filtered reports to monitor performance over time. Export this data into spreadsheets or business intelligence tools to build dashboards that help forecast budgets and fine-tune bid strategies for each segment.

If you’re a smaller business without in-house analytics expertise, consider partnering with a marketing agency like Big Drift Marketing. They can combine SEM data with website, email, and offline sales insights to create clearer seasonal strategies and align your messaging across channels. For instance, if you’re running a July 4 promotion that includes email and social media campaigns, adjusting your SEM bids to capture heightened search demand during that weekend can amplify your results.

How to Adjust Bids for Seasonal Campaigns

Once you've identified and segmented your seasonal patterns, the next step is fine-tuning your bids to maximize opportunities while keeping costs in check. Your approach - whether manual adjustments, automated strategies, or a mix of both - will play a big role in capturing seasonal demand. Here's how you can tackle each method effectively.

Setting Manual Bid Adjustments

Manual bid adjustments give you direct control over how much you're willing to spend based on factors like device type, location, and time of day. This method works best when you have clear historical data showing exactly when and where your seasonal spikes occur.

Take device bid adjustments, for instance. If mobile devices show a 30% higher conversion rate during holiday weekends, you might increase mobile bids by 20% to 40% during those periods. For many U.S. retailers, mobile traffic often surges in the evenings and on weekends in December, so you could leave desktop bids unchanged or even apply small negative adjustments if desktops underperform during those times.

Location-based bid adjustments can help you focus your budget on areas with stronger seasonal demand. For example, a ski equipment retailer might prioritize states like Colorado and Vermont in winter, while a beachwear brand might increase bids in coastal states as summer approaches. If you run physical stores, consider raising bids by about 30% within a 10- to 20-mile radius of your locations on major shopping days like Black Friday to attract local shoppers. On the flip side, you can apply negative adjustments to regions that consistently underperform to reallocate your budget more efficiently.

You can also adjust bids based on time of day and day of the week. Review past performance to identify when your audience is most active. For example, an e-commerce brand might raise bids by 25% during evenings and weekends in December, when shoppers are more likely to browse at home. For back-to-school campaigns, increasing bids during lunch breaks or after school hours could help you reach parents actively searching for supplies.

The real advantage of manual adjustments comes from layering multiple strategies together. For example, you can combine device, location, and time-based adjustments to fine-tune your approach. This method is particularly effective for short-term events like flash sales or when you need precise control in the absence of robust data. Many advertisers also use manual adjustments alongside automated strategies, such as Smart Bidding, to add an extra layer of precision.

If you're looking for a more hands-off approach during busy periods, consider switching to Smart Bidding.

Using Smart Bidding for Seasonal Adjustments

Smart Bidding uses machine learning to automatically adjust your bids in real time based on factors like device, location, time, and audience behavior. This approach can save time and optimize results, especially during periods of high demand.

For instance, if your goal is to drive a specific number of conversions at a set cost, Target CPA (Cost Per Acquisition) is a great option. You could create a separate campaign for a seasonal push - like "Holiday 2025 – Gifts" - and set a Target CPA based on past seasonal performance. If you usually aim for a $25 CPA, you might increase it to $35 in December if the higher conversion volume justifies the cost. Just remember to give the algorithm two to four weeks to adjust before your peak period.

If profitability is your main focus, Target ROAS (Return on Ad Spend) might be a better fit. For example, you might usually aim for a 400% ROAS but temporarily lower your target to 300% during high-volume events like Black Friday to capitalize on increased sales.

It's important to avoid making frequent, drastic changes to your targets during the season, as this can disrupt the algorithm's learning process. Instead, set your seasonal goals in advance and make gradual adjustments if necessary. While Smart Bidding performs well during volatile periods, combining it with manual tweaks can give you even better control over costs.

If you're unsure how to fine-tune these strategies, partnering with a marketing agency like Big Drift Marketing can be a smart move. They can analyze your historical data, recommend the best Smart Bidding approach, and handle ongoing optimizations during critical seasonal events.

Setting Up Seasonal Adjustment Windows

Seasonal adjustment windows are another tool that can refine your bidding strategy for short-term events. These windows let you inform your bidding algorithm about temporary changes in conversion rates, helping it adjust bids more effectively without overreacting once the event ends.

These adjustments are ideal for brief events like Black Friday, Cyber Monday, or flash sales - not for longer periods like an entire season. In fact, about 65% of advertisers actively use Google Ads' seasonality adjustment features specifically for Black Friday campaigns [1].

To set up a seasonal adjustment window, start by defining your event with precision. For example, if you're running a weekend flash sale, specify the exact start and end times in your ad platform using U.S. local time, such as Saturday 8:00 AM to Sunday 11:59 PM. Then, estimate the expected change in conversion rate based on past data. If last year's sale saw a 40% increase in conversions compared to a typical weekend, you might apply a +40% adjustment. This ensures the algorithm bids more aggressively during the event without assuming the spike will continue indefinitely.

How to Monitor and Refine Seasonal Bidding Strategies

Adjusting your bids is just the starting point. To truly make the most of your seasonal campaigns, you need to keep a close eye on performance and refine your approach as you go. Let’s explore how tracking metrics and running tests can help you fine-tune your strategy in real time.

Track Key Performance Indicators

Keep tabs on key metrics like cost per click (CPC), click-through rate (CTR),

conversion rate (CVR), cost per acquisition (CPA), and return on ad spend (ROAS) on a daily basis. Together, these metrics reveal whether your seasonal bids are bringing in quality traffic at a cost that makes sense for your goals.

It’s okay to accept a higher CPC if it results in better conversions and higher revenue. Start by pulling historical data from last year’s peak seasons or from the past four to six weeks of non-seasonal activity. This will help you establish benchmarks for CPC, impression share, CVR, CPA, and ROAS at the campaign level. Once your seasonal bids are live, compare daily performance against these benchmarks to identify trends. Watch for healthy seasonal lifts but also flag potential issues like an increasing CPA or a drop in impression share.

During high-stakes periods, such as Cyber Monday, monitor your key campaigns frequently - sometimes even every few hours. Set specific thresholds for action. For example, you might decide to pause or reduce bids if CPA rises 25% above your target over three consecutive days. On the flip side, you could increase bids if impression share falls below 70% while ROAS stays strong.

Break down your reports by device, location, and

audience to uncover seasonal trends. For instance, mobile devices might dominate last-minute holiday purchases, making it worth increasing mobile bids during key times. Similarly, certain states like California or New York might respond more positively to your promotions, justifying higher bids in those areas while scaling back in regions where CPA consistently misses your targets.

Run A/B Tests on Seasonal Bids

A/B testing is a powerful way to refine your seasonal bidding strategy. To get meaningful results, focus on testing just one variable at a time. For instance, you could apply a 20% higher bid adjustment for high-intent keywords in your test group while keeping everything else - ad copy, landing pages, and budgets - unchanged in the control group. This ensures that any differences in performance metrics like CPA, CVR, or ROAS can be attributed to the bid adjustment.

Make sure your tests run long enough to gather reliable data - ideally covering an entire seasonal cycle or several days of peak activity. Tools like Google Ads make it easy to set up experiments, split traffic, and compare KPI results side by side.

You can also segment your tests by audience or location. For example, an e-commerce brand might test aggressive bid increases for returning customers in high-value states while applying more conservative increases for new customers or less profitable regions. Compare metrics like CPA and ROAS across these segments to determine what works best for each group.

The ultimate goal isn’t just to optimize for the current season - it’s to create a playbook for future campaigns. Document what you tested, the results, and the lessons learned so you can build on those insights next time.

Use Performance Data for Future Planning

The data you gather from monitoring KPIs and running tests is invaluable for shaping future seasonal strategies. Compile detailed reports for each campaign and segment, and calculate seasonal lifts in metrics like CVR, CPC, CPA, and ROAS compared to your baseline periods. This helps you quantify the impact of your seasonal efforts.

These insights can guide your planning for next year. For instance, if you consistently see a 30% boost in conversion rates and a 15% increase in CPC during a specific holiday, you can factor those expectations into your future bids and budgets. This approach replaces guesswork with data-backed assumptions.

Seasonal reports often highlight patterns you can apply year after year. If mobile devices consistently outperform desktops during December evenings, you’ll know to prioritize mobile bid adjustments during those times. Similarly, if certain states or cities deliver stronger ROAS during back-to-school season, you can allocate more budget to those locations upfront.

Create post-season reports that summarize key metrics, test outcomes, and recommendations for the next year. Use a standardized template with sections for goals, baseline metrics, test details, KPI changes, and final suggestions. Store these reports in a shared system so your marketing, finance, and leadership teams can easily access and compare results year over year.

If managing this level of analysis feels overwhelming, consider partnering with a specialist agency like Big Drift Marketing. They can help you set up robust tracking systems, define realistic seasonal KPIs, and run structured experiments to maximize your ROAS during peak periods. They’ll also ensure your bidding strategy aligns with your creative assets, landing pages, and broader campaign goals.

Seasonal bidding isn’t a one-and-done task - it’s an ongoing process of monitoring, testing, and learning. The more disciplined you are about analyzing and applying data, the better your results will be - not just this season, but for every season ahead.

Conclusion

Adjusting your SEM bids to align with seasonal trends isn’t a one-and-done task - it’s an ongoing process that gets better with every cycle. Start by diving into your historical performance data from past seasonal peaks. This will help you pinpoint when demand surges and dips. Identify the critical dates for your business, whether that’s Black Friday, back-to-school shopping, or other industry-specific moments. By segmenting campaigns based on their sensitivity to seasonal trends, you can make more precise bid adjustments.

After laying the groundwork, select the bidding strategy that works best for your needs. Manual bid adjustments give you tight control during short, high-impact periods, while Smart Bidding with seasonality adjustments can handle longer stretches effectively - provided you have sufficient conversion data. Be sure to set clear start and end dates for each seasonal window, starting a few days before the expected surge and tapering off as demand levels out. This helps you avoid overspending after the peak passes.

When the peak season hits, execution is everything. Monitor your key performance indicators (KPIs) like click-through rate, conversion rate, cost per click, cost per acquisition, and return on ad spend (ROAS) daily - or even multiple times a day during high-demand periods. Consumer behavior and competition can shift rapidly, especially around major U.S. holidays, so keeping a close eye on the numbers allows you to adjust bids on the fly. Push bids higher when performance is strong and scale back when costs rise without delivering returns. Running A/B tests on various bid levels or strategies can also reveal what truly drives better outcomes.

"Marketing is wasted without returns. Great marketing tracks every dollar." – Big Drift Marketing

Once the seasonal rush is over, it’s time to evaluate. Compare your initial plans to the actual results, breaking it down by segment. Take note of which bid adjustments delivered the best ROAS, which devices or locations exceeded expectations, and where you might have overspent. This post-season analysis becomes your blueprint for the next cycle.

The difference between businesses that see strong returns and those that don’t often comes down to discipline - closely monitoring performance, testing strategies systematically, and using data to refine future plans.

If managing this process feels overwhelming, consider working with a performance-driven agency. Big Drift Marketing specializes in strategic SEM management and offers services like copywriting, landing page development, and email marketing to ensure your seasonal bid strategy aligns with your broader campaign goals.

Ready to take action? Pick one upcoming seasonal event - whether it’s a holiday, industry milestone, or quarterly peak - and create a detailed plan. Define the key dates, set your target KPIs, and outline your bid adjustments. Add calendar reminders to review performance during and after the event. By starting with the next season, you’ll gradually build a system you can rely on year after year.

FAQs

How do I identify which SEM campaigns are most affected by seasonal trends?

To figure out which of your SEM campaigns are most influenced by seasonal trends, start by digging into your historical performance data. Focus on key metrics like click-through rates (CTR), conversion rates, and

cost-per-click (CPC) to spot recurring patterns during specific times of the year. For instance, if you notice traffic or conversions surging around holidays or seasonal sales, it’s a sign those campaigns are tied to those periods.

Tools like Google Ads' Seasonality Adjustments or analytics platforms can also help uncover shifts in user behavior. Industries like retail during the holidays or travel in the summer often see strong seasonal demand, so keep a close eye on those. By recognizing these trends, you can make smarter budget decisions and fine-tune your bids to get the most out of peak periods.

Why is Smart Bidding a better choice than manual bidding during seasonal peaks?

Smart Bidding brings some clear advantages, especially during high-demand seasons when staying competitive is crucial. Using machine learning, it processes massive amounts of data - like past performance and real-time trends - to automatically fine-tune your bids. This means your campaigns can perform at their best without needing you to constantly monitor and tweak settings.

Another big plus? Smart Bidding adjusts seamlessly to seasonal shifts, such as the surge in searches during holidays. It ensures your ads reach the right audience exactly when they're looking. By embracing this automation, you not only save time but also set yourself up to get the most out of your ad spend.

How can I adjust SEM bids for short-term events like flash sales or weekend promos?

To make the most of your SEM bids for short-term events, it’s essential to match your strategy with the event’s urgency and timeframe. A good starting point is to boost bids on top-performing keywords that are highly relevant to the promotion. This approach ensures you capture more traffic when interest is at its peak.

Leverage ad scheduling to focus on the times or days when your audience is most likely to engage - like during the actual sale or promotional hours. Keep a close eye on performance metrics and be prepared to tweak bids in real-time if certain keywords or campaigns show stronger-than-expected results. This flexibility can help you get the best return on investment during these brief but critical windows of opportunity.