Why Cant I Sleep When its Hot? Summer Sleeplessness Explained
Lighter evenings, longer days and warmer weather are some of the best things about summer, but they can also make getting a good night's sleep more difficult. If you've ever found yourself lying awake wondering, ‘why can't I sleep when it's hot?’, you're not alone.
Hot weather can make it harder to fall asleep, increase the likelihood of waking during the night and leave you feeling less refreshed in the morning. Research suggests that when daytime temperatures rise above 25°C, people lose an average of 13.3 minutes of sleep each night.[i] During a recent UK heatwave, almost two-thirds (65%) of UK adults reported struggling to sleep.[ii]
In this blog, we explain why hot weather can affect your sleep and share simple tips to help you stay cool during the summer months.
Why does hot weather make it harder to fall asleep?
Your body naturally cools down before bedtime as part of its internal sleep-wake cycle. This drop in core body temperature helps signal that it's time to sleep.
When your bedroom is too warm, your body must work harder to lose heat. As a result, it can take longer to fall asleep and you're more likely to wake during the night.
Summer can also affect sleep in other ways, including:
- Longer daylight hours delaying your natural body clock
- Hot, humid bedrooms making it difficult to stay comfortable
- Holidays, travel and social events disrupting normal routines
- Increased outdoor noise or sleeping with windows open making it easier for sleep to be disturbed
Even if you don't remember waking during the night, heat can still disrupt your sleep, reducing sleep quality and leaving you feeling tired, groggy and less able to concentrate the next day.
How to stay cool this summer
While you can't control the weather, there are plenty of easy ways to stay cooler during the hot summer nights. Consider making a few small adjustments to your evening routine and bedroom environment to help maintain good sleep habits when temperatures rise.
- Don't let the sunset fool you: Longer evenings can make it tempting to stay up later, but sticking to a regular bedtime helps keep your internal body clock on track. Try to wind down and head to bed at your usual time, regardless of how much daylight is left.
- Create a ‘switch off’ ritual: Instead of going straight from a busy day to bed, give yourself 30-60 minutes to unwind. Whether it's reading a few pages, stretching or listening to a calming playlist, a consistent wind-down routine can help signal that sleep is next.
- Try a warm shower before bed: Taking a warm shower, rather than a hot or cold one, about an hour before bed can help your body cool down afterwards. As your core temperature naturally drops, it helps signal that it's time to sleep, making it easier to drift off, even on a warm night.
- Choose cooler bedding and sleepwear: Sleeping under a heavy duvet or wearing thick pyjamas can make it harder for your body to lose heat. Opt for a lighter tog or cotton sheet, along with lightweight sleepwear made from breathable fabrics, to help you stay cooler through the night.
- Make the fan work harder: Place a bowl of ice or a frozen water bottle in front of your fan to create a cooler breeze. If the evening air outside is cooler than indoors, position the fan facing out of an open window to help push warm air outside. Open another window elsewhere in the room or house to encourage cooler air to flow in.
- Consider a traditional herbal remedy: If you've tried these simple tips and are still struggling to switch off at bedtime, a traditional herbal remedy may be worth considering. Kalms Night One-A-Night contains valerian root extract and can be used for the temporary relief of sleep disturbances. For more information on the Kalms Night range, click here.
Everyone experiences the occasional restless night, particularly during the summer months. By making a few simple changes to your bedtime routine and sleep environment, you may find it easier to maintain good sleep habits, even when temperatures rise.
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Posted by Elizabeth Hughes-Gapper
16th July 2026
