When the weather turns hot, one of the kindest things you can do for your body is also one of the simplest: drink a little more. On a sweltering summer day you can lose surprising amounts of fluid just sitting still, and by the time you feel thirsty you're often already behind. So how much do you really need — and how do you get there without carrying a two-litre bottle around like a security blanket? Let's keep it practical.
Start with a realistic baseline
As a general guide, adequate daily water intake is around 2 litres for women and 2.5 litres for men — and that figure includes the water in your food as well as everything you drink. In everyday terms, the NHS suggests aiming for roughly six to eight glasses of fluid a day. That's your starting point in mild weather; summer simply nudges it upwards.
Summer raises the bill
Heat and sweating increase how much fluid you lose, so your needs genuinely go up when it's hot or when you're active outdoors. There's no single magic number — a still day on the sofa is very different from an afternoon gardening in full sun — but the principle is easy: on hot days, drink a bit more than usual, and more still if you're sweating. The goal isn't to flood yourself; it's to gently replace what the heat is taking.
Let your body tell you
You don't need to count every millilitre. Two simple signals do most of the work:
- Urine colour. Pale, straw-coloured urine usually means you're well hydrated; dark yellow is a nudge to drink more.
- Thirst — but don't wait for it. Thirst tends to lag behind, especially in older adults, so sip through the day rather than waiting until you feel parched.
Easy ways to top up
Water is the obvious choice, but it's far from the only one:
- Eat your water. Cucumber, watermelon, tomatoes, oranges and salad leaves are full of fluid — a summer plate does quiet hydration work for you.
- Keep it interesting. Add lemon, mint, cucumber or a few berries to a jug of water; herbal and fruit teas (hot or iced) count too.
- Anchor drinks to habits. A glass with each meal, one when you wake, one mid-afternoon — hydration is easier as a routine than as a target.
- Carry a bottle. Something visible and refillable makes topping up automatic when you're out in the heat.
A gentle word on the extremes
Go easy on alcohol on hot days — it encourages your body to lose fluid rather than keep it. And more isn't endlessly better: drinking enormous quantities of water very quickly isn't necessary for most people and can occasionally do harm, so steady sipping beats heroic gulping. Some people also need extra care in the heat — older adults, young children, and anyone with a heart, kidney or other condition, or on medication that affects fluid balance — so if that's you or someone you look after, follow the specific advice you've been given.
The takeaway? In summer, hydration is less about hitting a perfect number and more about topping up a little more often. Keep water within reach, lean on water-rich fruits and vegetables, check that your urine stays pale, and drink a bit extra whenever the day heats up. Your energy, your concentration and your mood will all quietly thank you.
This article is for general information and isn't a substitute for individualised advice from your own doctor or dietitian.
Merve Tığlı, Dietitian
Sources: European Food Safety Authority (EFSA) — Scientific Opinion on Dietary Reference Values for water (2010); NHS — Water, drinks and hydration; NHS (Kent Community Health) — Keeping hydrated during hot weather.