Hundreds of schools across England and Wales have announced at least partial closures as the nation braces for a significant heatwave. The closures come ahead of a rare red extreme heat warning issued by the Met Office, which is in effect from Wednesday morning to Thursday evening.

This red warning signifies an exceptional spell of hot and humid weather, with potential dangers to life. The Met Office has forecast temperatures to reach around 37 or 38C in southern England on Wednesday, with a possibility of reaching 39C. High humidity will make the conditions feel even more intense, with a 35C temperature potentially feeling like 41C.

Multiple train operators, including the UK's largest, have urged passengers not to travel unless absolutely necessary due to the extreme heat. Northern Ireland and Scotland recorded their hottest days of the year on Tuesday, with temperatures reaching 28.1C and 29C respectively, while Wales saw a high of 32.2C. The top temperature nationwide on Tuesday was 34.6C in Wisley, Surrey.

The implications of the heatwave extend beyond personal discomfort. The Met Office warns of a risk of serious illness and potential failure of heat-sensitive essential services such as power and water. Coastal areas, lakes, and rivers are also expected to see increased visitor numbers, raising concerns about water safety incidents.

This heatwave has the potential to break the UK's record for the highest June temperature, which stands at 35.6C set in 1976. However, the all-time UK high of 40.3C, recorded in 2022, is not expected to be surpassed. Tuesday's temperatures in south-east England were slightly lower than predicted due to overnight rainfall and localized flash flooding.

A red heat health alert has also been issued by the UK Health Security Agency (UKHSA), running from Wednesday to Thursday. Professor Robin May, chief scientific officer at the UKHSA, noted this is only the second time this highest level of warning has been issued, the previous instance being in July 2022. He emphasized that the warning signals a widespread threat, affecting not only the typically vulnerable but also otherwise healthy individuals.

Professor May specifically stated that the heat could have serious, life-threatening effects even on fit individuals, urging everyone to take very cautious steps. The UKHSA's alert highlights the significant risk to public health posed by the extreme temperatures.

Matthew Hopkins, representing the NHS alliance for acute and ambulance networks, anticipates increased demand on emergency services over the coming days. He indicated that the extreme weather conditions are expected to place a considerable strain on healthcare provisions as the heatwave intensifies.