As a sweltering heatwave grips the capital, Londoners are facing four tropical nights as temperatures hit 31C at as late as 11pm.
Day time temperatures will peak at 40C by Wednesday in London, with the temperature never dropping below 20C at night from Tuesday night to Friday night.
A tropical night is defined as when temperatures do not drop below 20C, according to the Met Office.
Monday night will be the last night with temperature below the “tropical night” threshold, before four consecutive nights of sweltering heat, even once the sun has gone down.
From Tuesday, Londoners can expect temperatures as high as 27C at midnight. Though the temperature will drop to 25C by 3am, getting any shuteye may prove a challenge across the capital.
Wednesday night will be the warmest with temperatures peaking at 31C at 11pm.
There will be little respite as temperatures edge 30C on Thursday night and around 25C on Friday night.
London previously suffered three tropical nights in August 2020, measured at St James’s Park, Westminster, and is predicted to beat that record this week.
Dr Yimmy Chow, London regional deputy director for the UK Health Security Agency (UKHSA) , told The Standard: “When it stays hot overnight following a hot day, the body is denied that vital window to cool down and recover, and this is associated with greater mortality risk, particularly for people aged over 65 years or those with pre-existing health conditions.”
Dr Chow added: “Keeping hydrated during a heatwave is essential for replacing water lost through sweating, so drink plenty of fluids and avoid excess alcohol as it dehydrates the body.
“It’s important to keep homes cool, so close blinds and curtains during the day, turn off lights and electrical equipment that are not in use, and consider moving to a cooler part of the house, especially for sleeping.
“If you have friends, family or neighbours who are more vulnerable, it is important to check in on them and ensure they are aware of the forecasts and the health advice.”
Health experts are also warning that middle-aged Londoners are at just as high a risk in a heatwave than pensioners.
The Met Office has issued an red “extreme” alert for London between Wednesday and Thursday, warning of “exceptional spell of hot and humid weather” across the region.
On the impact on people, the Met Office said: “The heat will be accompanied by high humidity, exacerbating the potential for discomfort and health impacts, with very warm and humid night times also reducing the ability for people to recover overnight.
“Significant disruption to daily life is likely and the public should take every effort to make precautions and adapt their daily routines where possible to cope with these levels of heat, which up to now have been extremely rare for the UK.”
The UKHSA has issued guidance on heatwaves and nighttime temperatures including:
- Close blinds and curtains on windows that are exposed to direct sunlight during the day
- Move to a cooler part of the house, especially for sleeping
- Open windows (if it is safe to) when the air feels cooler outside than inside, for example at night, and try to get air flowing through your home
- Use electric fans if the air temperature is below 35°C, but do not aim the fan directly at your body as this can lead to dehydration
- Check that any heating is turned off
- Turn off lights and electrical equipment that are not in use
- Go outside if it is cooler outside in the shade
Other advice from sleep experts includes cool your feet before bed by running cold water over them, sleep on your side so more heat can escape from your body, and drink enough water to stay hydrated but not too much right before you go to sleep to avoid waking up during the night.
Guidance also includes take a lukewarm but not cold shower as the latter can increase body temperature, wear cool pyjamas (or nothing at all) in bed, exercise earlier in the day, and try not to nap during the day.
People can also put a cold flannel in the fridge for a few hours then place it on their forehead to cool down as they doze off, or fill a hot water bottle with cold water, put it in the freezer, and then take it to bed.
