Heatwaves, holidays and happy brains: why summer changes the way we spend

By Staci West on 1 August 2026 in Basics

If you’re reading this from your garden with an iced coffee in one hand and a half-finished DIY project in front of you… I see you. Mainly because I’m writing this from my garden with an iced coffee in one hand and a handful of half-finished DIY projects in front of me.

Every year, it happens without fail. The first proper heatwave arrives and suddenly my husband is showing me just one more set of garden furniture. We pop to the garden centre “just to have a look” and somehow leave with enough plants to start our own botanical garden. The patio suddenly looks tired, so out comes the power washer. Then the old outdoor cushions don’t quite match the new flowers. The barbecue we’ve had for years suddenly seems… inadequate.

By Sunday evening we’ve somehow spent several hundred pounds making the garden the perfect place to spend summer. And then, because we’ve spent all day gardening, we’re far too tired to cook. So naturally we head to the local pub, sit in the sunshine and another £100 quietly disappears.

Christmas gets all the attention when people talk about overspending, but honestly? Summer has become a close second in our house.

The interesting question isn’t why do we spend more? It’s why does spending suddenly feel like such a good idea?

Sunshine changes more than the weather

It turns out our brains behave differently in summer. Longer days and warmer weather can increase the production of serotonin and dopamine, chemicals associated with happiness, reward and motivation. We generally feel more optimistic, more sociable and more willing to say “yes” to experiences. That upbeat mood doesn’t just affect our social calendar, it can influence our financial decisions too.

Psychologists have found that when we’re feeling positive, we tend to perceive less risk. We become more optimistic about the future, more confident in our decisions and a little less concerned about the consequences of spending today. Hence, the extra flowers!

Behavioural finance has a name for part of this: present bias.

This is our tendency to place greater value on immediate enjoyment than future rewards. Future me would probably appreciate having another few hundred pounds in the ISA. But present me would quite like matching outdoor cushions and a new deck chair.

It’s not just you

Think about how summer unfolds: There’s another barbecue. A friend’s birthday in a beer garden. Ice cream because it’s hot. Iced coffee because you’ve walked in the sun. A day trip because the weather’s finally nice. A weekend away because “we should make the most of it.” Individually, none of these decisions feels extravagant. Together, they quietly become one of the most expensive months of the year.

There’s another behavioural concept at work too: social proof.

This is when everyone around us seems to be making the most of the sunshine, it’s easy to feel like we should be doing exactly the same. We don’t want to waste the weather because, let’s face it, we live in the UK. We all know it could be raining again next week.

That creates a subtle sense of urgency. Enjoy it now. Buy it now. Book it now.

Enjoy summer, just don’t let your brain spend for you

None of this means you shouldn’t enjoy summer. Some of my favourite memories involve spontaneous pub lunches, long evenings in the garden and buying far too many plants that absolutely did not fit in the car.

It might be an unpopular opinion but I believe that money is there to improve our lives, not simply accumulate in a savings account. The trick is recognising when your brain is making the decision before you’ve really thought it through.

Sometimes it’s worth pausing and asking yourself one simple question: “Do I genuinely want this, or am I just in a really good mood?”

It sounds almost too simple, but that tiny pause is often enough to stop an impulse purchase or reassure yourself that it’s something you’ll genuinely enjoy.

Behavioural finance isn’t about removing emotion from money. That’s impossible. It’s about recognising that we’re all human. Even those of us who spend our days writing about investing can find ourselves standing in a garden centre, looking at a decorative olive tree, wondering how on earth it ended up in the trolley.

Understanding why we make financial decisions is often more valuable than knowing what investment to buy next. And that’s exactly why I find the psychology of money so fascinating. Because once you understand your own behaviour, you’re already one step closer to becoming a better investor and, dare I say, a slightly more intentional summer spender.

Want to learn more about behavioural finance? Read our quick 3-minute guide here.