The Amber warning, which has been issued for Sunday (17 July) and Monday (18 July), highlights likely adverse health effects for the public, not just limited to those most vulnerable to extreme heat. Temperatures could be in excess of 35°C in the southeast, and more widely around 32°C within the warning area. These high temperatures could extend further into next week and an extension of the warning will be considered in the coming days.  

This week 

The Amber Warning comes at the end of a week when the UK will see widely-above average temperatures, with a Level 3 UK Health Security Agency Heat Health Alert in place for southeastern areas this week, and a Level 2 alert for much of the rest of England.  

Heatwave criteria, when specific temperature thresholds must be exceeded three days running, will be met for many locations in southern and central England and Wales early this week. Temperatures on Tuesday could peak at 31°C in the southeast, although there will be more in the way of cloud. Cooler conditions will have spread to Scotland, Northern Ireland and the north of England along with some showers in the northwest. 

Warm summer conditions will remain in place for much of the week for the majority of England and Wales, albeit slightly less hot on Wednesday and Thursday, when temperatures are more likely to peak in the high 20s Celsius.  

A persistent area of high pressure centred over the southern half of the UK is responsible for this week’s warm spell, bringing largely dry and clear weather for the week, with little cooling into the evenings. During the weekend, a developing southerly flow will allow very high temperatures currently building over the continent to spread northwards to the UK. 

Met Office Deputy Chief Meteorologist Rebekah Sherwin said: “Today (12 July), temperatures are likely to peak at 31°C in the southeast, with warm weather likely to continue throughout this week and it looks likely to ramp up late this week and into early next week.  

“From Sunday and into Monday, temperatures are likely to be in excess of 35°C in the southeast, although the details still remain uncertain. Elsewhere, temperatures could be fairly widely above 32°C in England and Wales, and in the mid-to-high 20s Celsius further north.” 

Dr Agostinho Sousa, Head of Extreme Events and Health Protection at UKHSA, said: “Heat-health alerts have now been issued to the majority of the country, with temperatures set to remain consistently high throughout the duration of this week. 

“Most of us can enjoy the hot weather when it arrives, but it is important to keep yourself hydrated and to find shade where possible when UV rays are strongest, between 11am and 3pm. 

“If you have vulnerable family, friends and neighbours, make sure they are aware of how they can keep themselves protected from the warm weather.’’  

Government advice is that 999 services should be used in emergencies only; seek advice from 111 if you need non-emergency health advice. 

Find out more about keeping cool in hot weather with WeatherReady from the Met Office. 

Will we get record-breaking heat?  

The record high temperature in the UK is 38.7°C, which was reached at Cambridge Botanic Garden on 25 July 2019.  

The Met Office’s Rebekah Sherwin added: “Weather forecast models are run hundreds of times to determine the most likely weather outcome. For late in next weekend and early next week, some runs of these models are allowing exceptionally high temperatures to develop, which is something we’ll be monitoring closely and adding details in the coming days.  

“Some models have been producing maximum temperatures in excess of 40°C in parts of the UK over the coming weekend and beyond. At longer time scales temperature forecasts become less reliable, so whilst these figures can’t be ruled out, they are still only a low probability. A number of weather scenarios are still possible and at the current time, mid- or perhaps high-30s are looking more likely.” 

Climate change 

Whilst a 1°C background temperature increase may not seem significant, the resulting increase in the severity of extreme heat events is already evident in the observed record. This has widespread and significant impacts. 

Extreme heat events do occur within natural climate variation due to changes in global weather patterns. However, the increase in the frequency, duration, and intensity of these events over recent decades is clearly linked to the observed warming of the planet and can be attributed to human activity. 

Dr Mark McCarthy is the head of the Met Office National Climate Information Centre. He said: “The highest temperatures experienced in the UK tend to occur when our weather is influenced by air masses from continental Europe or North Africa – as it will be at the weekend - there is already a strongly-embedded warming due to climate change across the continent, that is increasing the likelihood of challenging the existing UK temperature record.”