The fourth heatwave of the summer has been forecast to send temperatures soaring in Brighton and Hove.
The air could become humid as temperatures climb towards the mid-30s – or the mid-90s on the Fahrenheit scale.
The UK Health Security Agency and the Met Office issued an amber heat-health alert and shared advice for coping with the hot weather.
The Met Office said that there could be thundery showers before another surge in temperature going into next weekend.
The official forecaster said: “Warmth is building for many in the coming days, with much of central and southern England likely to reach heatwave criteria by midweek.”
The heatwave criteria for Brighton and Hove are daily maximum temperatures exceeding 27C or about 81F for three days running.
The Met Office said: “A combination of high pressure and a southerly airflow will see temperatures rise for much of England and Wales in the first half of the week.”
They could top 30C (86F) for some today (Monday) and were forecast to peak tomorrow towards the mid-30s in London.
The Met Office’s deputy chief meteorologist Tom Crabtree said: “Warmth is the focus in the forecast in the first half of this week, with temperatures likely to peak on Tuesday around the mid-30s, but remaining above average in the second half of the week, particularly further to the south east.
“Outbreaks of rain, some of which could be thundery, are possible in southern and western areas for a time on Monday evening spreading north and east through the night, though this will be fairly hit-and-miss and for many the weather will be a dry and warm day.
“While there’s a fair degree of uncertainty at this range, the main signal for more frequent thundery showers arrives from the south late on Wednesday and into Thursday.”
The Met Office added: “After that interlude of more unsettled weather, the most likely scenario is for high pressure to influence the UK’s weather into next weekend, with predominantly dry conditions with variable cloud and sunny spells.
“There could, however, still be some isolated thunderstorms, most likely in the south.”
The UK Health Security Agency and the Met Office have issued an amber heat-health alert, meaning that the effects of the weather are likely to be felt across the whole health service.
The agency said: “At this level, we may begin to see some health impacts across the wider population.
“We may also see an increase in risk to health for individuals aged over 65 years or those with pre-existing health conditions, including respiratory and cardiovascular diseases.”
The alert is in force from 9am tomorrow (Tuesday 12 August) until 6pm on Wednesday (13 August).
UK Health Security Agency public health consultant Paul Coleman said: “Temperatures are forecast to rise above 30°C across central and southern parts of the country over the next few days.
“These kind of temperatures can result in serious health outcomes across the population – particularly in those who are vulnerable such as the elderly or those with serious health conditions – so it is important that everyone takes sensible precautions while enjoying the sun.
“If you have friends, family or neighbours who are vulnerable, it is important to ensure they are aware of the forecasts and are following the necessary advice.
“Check in on them if you can to make sure they know that hot weather is on the way and how to keep themselves safe.”
