As summer winds down in the UK, many pool owners ask themselves the same question: “Should I keep my pool running into September, or is it better to close it down?”
With energy prices high, the weather turning unpredictable, and families getting back into their routines, it’s a decision worth weighing carefully. Let’s break down the pros and cons so you can make the right call for your pool — and your wallet.
Is September Still Swimming Season in the UK?
In some parts of the world, September is still warm enough to enjoy a daily swim. Here in the UK, though, things are less predictable. Early September can sometimes feel like an extension of summer, but more often than not, cooler evenings and shorter days make swimming less appealing.
- Average UK temperatures in September: 13°C – 18°C (and even lower at night)
- Daylight hours: By mid-September, you’ve lost nearly three hours of light compared to July
- Heating costs: To keep your pool comfortably warm (around 26–28°C), your heater may need to work twice as hard as it did in July
In short, unless you’re planning to use your pool regularly, keeping it open just for the occasional dip can become costly.
Check out our article Should I Still Swim in My Pool in September? to make sure your swimming safe.
The Case for Keeping Your Pool Running Into September
That said, there are some good reasons you might want to keep pool running in September UK:
1. You’re Still Swimming Regularly
If your family (or the kids) are still enjoying the pool, then it makes sense to keep it running. After all, the whole point of owning a pool is to use it.
2. You’ve Got a Heater or Pool Cover
A high-quality solar cover or heat pump can make September swimming much more practical, helping retain warmth and reducing running costs.
3. Preventing Green Water
Some pool owners prefer to keep everything circulating until October to avoid the risk of algae blooms. Shutting down too early, especially in a mild September, can create a green headache to deal with later.
The Case for Closing Your Pool at the End of August
For many UK pool owners, the smarter choice is to shut down before September really begins. Here’s why:
1. Energy Bills
Running pumps, filters, and heaters for a pool you’re barely using can add hundreds of pounds to your energy costs. If you’re not swimming regularly, that money is better spent elsewhere.
2. Maintenance Effort
The longer you keep your pool open, the more testing, balancing, and cleaning you’ll need to do. By closing earlier, you reduce the time and effort spent keeping water clear when usage is low.
3. Protecting Your Pool Over Winter
Closing your pool properly at the end of summer helps protect it during the colder months. Winterising early means less chance of damage, fewer algae problems, and an easier opening next spring.
How to Decide: Keep Running or Close It Down?
The choice really comes down to usage versus cost:
Keep it running if:
- You’re still swimming at least a few times per week
- You have an efficient heating system or insulated cover
- You enjoy extending the swimming season into early autum
Close it down if:
- The pool isn’t being used much after the school holidays
- You’re concerned about rising energy bills
- You’d rather winterise and forget about it until spring
Think about your family’s habits. If no one has been in the pool since the August Bank Holiday, that’s usually a good sign it’s time to close.
Final Thoughts
For most UK pool owners, it makes more sense to close your pool at the end of August or very start of September. The costs of heating and running it rarely balance out against how much use you’ll actually get once the cooler weather sets in.
That said, if you’re a dedicated swimmer with a reliable heating setup, there’s no reason you can’t squeeze out a few extra weeks of enjoyment.
💧 Need help deciding or want advice on closing your pool?
Ask us directly for Free Expert Pool Advice here: Ask The Pool Chap
