Rare weather phenomenon's “tropical nights” are set to leave parts of Essex struggling to cool down as a rare red warning for extreme heat comes into force.
A red weather warning for extreme heat has been issued for parts of Essex from 9am on Wednesday until 9pm on Thursday.
The alert covers areas including Grays, South Ockendon, Purfleet, Warley, Harlow and Chipping Ongar.
Forecasters say temperatures could climb towards 39C in the worst‑affected spots.
The Met Office has warned of an “exceptional spell of hot and humid weather” for the county.
Officials say impacts to the general population are “highly likely” rather than confined to those who are already vulnerable.
There is also concern over a “high risk of failure” of heat‑sensitive systems and equipment, potentially affecting power and other essential services.
The UK Health Security Agency has issued a separate red heat‑health alert for the whole of Essex.
This is its most severe alert level and will be in place from 1am on Wednesday until 11pm on Thursday.
Health leaders say severe impacts are expected across health and social care, with an increased risk to life, particularly among older people and those with underlying conditions.
Forecasters say the county will get little relief overnight, with humid air bringing the prospect of so‑called “tropical nights”.
These occur when temperatures do not fall below around 20C, leaving homes feeling muggy and making it harder for people to sleep.
BBC forecasts for towns including Chelmsford, Braintree, Basildon, Southend and Colchester show daytime highs in the mid‑30s and night‑time values staying in the high teens or around 20C through the middle of the week.
Chelmsford
- Tuesday night into Wednesday – 20C
- Wednesday night into Thursday – 19–20C (borderline, likely to feel tropical)
- Thursday night into Friday – 21C
Braintree
- Tuesday night into Wednesday – 17C (close, but not quite 20C)
- Wednesday night into Thursday – 17C (very warm but below 20C)
- Thursday night into Friday – 20C
Basildon
- Tuesday night into Wednesday – 20C
- Wednesday night into Thursday – 19–20C (borderline tropical)
- Thursday night into Friday – 21C
Southend-on-Sea
- Tuesday night into Wednesday – 19C (very warm)
- Wednesday night into Thursday – 18–19C (very warm)
- Thursday night into Friday – 19–21C (borderline tropical on the higher end)
Colchester
- Tuesday night into Wednesday – 17C (very warm)
- Wednesday night into Thursday – 17C (very warm)
- Thursday night into Friday – 20C
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Health chiefs are urging people across Essex to treat the heat as seriously as other forms of severe weather.
Residents are being advised to drink plenty of fluids, avoid alcohol, and stay out of the sun between 11am and 3pm where possible.
Met Office meteorologist Simon Partridge described the conditions as a “very unusual, very rare spell of very hot weather”.
He said everyone in Essex was likely to feel the impact, warning that the particularly warm nights meant many people would not get as much sleep as usual.
The current record for the hottest June day in the UK stands at about 35C, set in the 1970s.
Forecasters say Essex could challenge or even beat that record if temperatures reach the upper end of current predictions.
Anyone concerned about their own health or someone else’s during the heatwave is being advised to contact NHS 111 for guidance.
