Why Summer Slumps Aren't Inevitable

Summer 2025 is officially over, and whilst most eCommerce businesses breathed a sigh of relief after surviving another 'inevitable' slow season, one team discovered something remarkable: they grew 19% year-on-year during what should have been their worst period. Matt Edmundson reveals the post-summer analysis that challenged everything we assume about seasonal trading. By questioning one simple default assumption - that summer slumps are inevitable - and understanding that August performance depends on March and April planning, this approach transformed summer from a write-off period into a competitive advantage. Discover why 70% of summer purchases happen in March-May, how mobile browsing intensifies during summer months, and why weather patterns create predictable opportunities rather than obstacles. Most importantly, learn the systematic process for challenging defaults that could transform your next summer trading period. Key Point Timestamps: 02:00 - The Default Assumption Problem 05:00 - Why One Team Grew 19% During Summer 08:00 - The Baltic States' Summer Strategy 12:00 - March Planning Drives August Performance 16:00 - The Weather Connection We All Missed 21:00 - Mobile Optimisation as Summer Strategy 26:00 - Three Steps to Challenge Your Seasonal DefaultsThe Default Assumption Problem (02:00) Matt opens with a provocative question: why are we so comfortable with predictions that essentially amount to "our business will perform badly for the next three months"? "We're planning for our businesses to underperform for a quarter of the year. And we call this acceptable business practice," Matt explains. These default assumptions - that sales drop in August, nothing happens after Father's Day until September, that it's just how these businesses work in summer - become self-fulfilling prophecies. When entire industries expect decreased activity, they collectively create the conditions that make it true by reducing marketing spend, operating skeleton crews, and delaying product launches until September.Why One Team Grew 19% During Summer (05:00) The post-summer analysis revealed a stark contrast between two teams. One experienced the predicted 50% sales drop from peak. The other grew 19% year-on-year during their slowest period. "What's been nagging at me - 80% of that growth was from new customers rather than just doing discounted offers to existing customers," Matt shares. The successful team challenged the default by staying engaged when competitors pulled back, focusing on mobile optimisation when browsing intensified, and ramping up marketing during a period when ad costs were lower. The impact extended beyond summer - by mid-September, they were already 25% ahead on sales compared to the previous year.March Planning Drives August Performance (12:00) Perhaps the most crucial insight: "August performance isn't dependent on what we do in August. It is dependent on what we do in March and April." Research shows that 70% of consumers made their summer purchases in March, April, and May - only 19% waited until June. "We weren't just experiencing summer slumps," Matt reveals. "We were missing the planning window that drives summer performance." This means that scrambling for summer offers in July is already too late. The businesses that thrived during summer 2025 were those that ramped up marketing in spring, when customers were making summer purchase decisions.The Weather Connection We All Missed (16:00) During UK heatwaves, web revenues fell 47.8% during peak temperatures. But here's what most businesses missed: revenues increased 17.4% in the week before the heatwave as people prepared for extreme conditions. "This perfectly illustrates why conversion matters more when traffic patterns shift," Matt explains. "During summer, if mobile browsing