- London and the south-east need three straight days of 28C.
- Northern Britain needs three straight days of 25C.
For much of this week, most of the UK is expected to stay below those official marks. By Friday, however, parts of Greater London and the Home Counties could just reach 28C.
By Sunday, top temperatures could rise to 30C. That means a few places in England could see a heatwave declared at the earliest point in this spell.
How hot is it expected to get next week?
Temperatures are forecast to climb more widely next week, especially across southern Britain, where hot air is expected to become more established.
Highs could approach or exceed 30C on most days, though the exact locations and daily peaks may shift. Initially, winds are expected to come mostly from the west, which may help prevent the more extreme levels seen during the second half of June.
Later in the week, there is a chance that southerly winds could briefly return and lift temperatures a little higher. That part of the forecast remains uncertain, so the sensible approach is not to start naming the pavement yet.
The UK Health Security Agency has issued yellow heat health alerts for the East Midlands, East of England, London, the south-east and the south-west. The alerts warn of a greater risk to life for vulnerable people as temperatures rise.
Will it feel as uncomfortable as the last hot spell?
One difference from the most recent heatwave is humidity. At least at first, the air is expected to be less humid, which means the heat may feel slightly more comfortable despite the high temperatures.
That does not make the heat risk irrelevant. Prolonged hot weather can still affect older people, those with health conditions, young children and people who cannot easily keep cool indoors or at work.
The warning signs are familiar, even if nobody is thrilled to see them again: warmer nights, hotter afternoons and another round of public health messaging about shade, fluids and checking on people who may be more exposed.
Why northern areas may stay cooler
The heat is not expected to affect the UK evenly. Northern Ireland, Scotland and northern England may not reach heatwave criteria as quickly, if they do so at all.
That is because the main area of high pressure may sit a little farther south. This would allow fresher Atlantic air, and possibly scattered rain clouds, to move into northern areas, especially because they are closer to the jet stream.
Temperatures in Belfast, Liverpool and Glasgow are expected to settle at a much milder 20C to 24C. In other words, warm enough for summer plans, but not quite the full “check the official threshold” routine.
For southern Britain, though, the signal is clear: another hot spell is building, and an official heatwave declaration is increasingly likely in the coming days.
