A yellow heat health alert has been issued across London as temperatures are set to soar hotter than those in Ibiza.

The alert will start tomorrow (Thursday) at 5pm and will end at 11pm on Saturday, July 20, 2024.

Minor impacts are expected across the health and social care sector, including increased use of healthcare services by vulnerable populations, a higher risk of mortality among vulnerable individuals, and an increased potential for indoor environments to become very warm.

The alert has been issued as London is about to experience a mini heatwave over the next couple of days, with temperatures eventually reaching 32C on Friday (July 19), making it the hottest day of the year.

On the same day, temperatures in Ibiza across the Mediterranean Sea will be 28C.

By Saturday, July 20, temperatures are expected to reach up to 28C in London before the heat alert ends at 11pm.

Unlike a weather warning, the Heat Health Alert is specifically aimed at health and social care professionals. While the heat is not likely to affect most people, it poses a risk to vulnerable individuals, including the elderly with multiple health conditions.

Met Office spokesperson Nicola Maxey said night-time temperatures could stay in the low 20s for parts of south-east England – officially classified as “tropical nights” if they do not drop below 20C – with there being health implications for the elderly or infirm.

She said there was still uncertainty over how soon the milder conditions would come in, with the possibility that the Southeast could retain its heat a little longer than elsewhere.

Forecast in full

Today: A fine, dry start to the day with sunny spells becoming lengthy into the evening. It will feel warm in the sunshine with light winds. Maximum temperature 24 °C.

Tonight: Plenty of warm, evening sunshine some high cloud overnight but still seeing plenty of clear spells, perhaps the odd isolated mist or fog patch. Remaining dry with light winds. Minimum temperature 11 °C.

Thursday: Mostly cloudy but remaining dry. Feeling warm or hot with sunny spells developing through the morning and light winds continuing. Maximum temperature 27 °C.

Outlook for Friday to Sunday: Settled weather with plenty of hazy sunshine over the coming days, staying dry aside from Saturday where there's a risk of showers, perhaps thundery. Temperatures turning warm or very warm.