The UK Health Security Agency has issued a yellow heat-health alert for most of England as temperatures are expected to reach up to 32C (89.6F) midweek.
This heat-health warning applies to seven regions and will remain in effect until 21:00 BST on Sunday, urging extra caution for the elderly and individuals with pre-existing health conditions.
Wales will also experience high temperatures, while some areas of Scotland and Northern Ireland may witness "unseasonably high temperatures."
The regions covered by the alert include London, the South East, the South West, the East and West Midlands, the East, North West, and Yorkshire and Humber.
On Monday, temperatures in southern England and south-east Wales reached 30C, according to the Met Office.
The warm weather follows a summer that has been generally characterized by poor weather across much of the UK. While July was notably wetter and cooler than usual, with temperatures rarely exceeding 20C, the previous month was the hottest June on record in the UK.
High temperatures are forecast to continue, with highs of 31C expected on Tuesday, according to Met Office spokesman Oli Claydon. He noted that Wednesday and Thursday could see even higher temperatures of 31C or possibly 32C, particularly in the south-east and central England.
Claydon also warned that Wednesday night could be unusually warm, with temperatures possibly remaining above 20C, creating a "tropical night." A similar scenario could occur on Thursday.
The Met Office attributes the current weather pattern to tropical storms in the western Atlantic and deep areas of low pressure, which have amplified the jet stream over the Atlantic Ocean, leading to high pressure dominating over the UK.
Although temperatures could reach 31C on Friday, the far north-west of Scotland may experience cloudier conditions and a chance of rain.
The heatwave is expected to end next week when average temperatures return. Heatwaves are becoming more frequent and severe due to climate change, and last year, the UK recorded temperatures exceeding 40C for the first time, a phenomenon scientists attributed to climate change.
Additionally, the Met Office has attributed the recent picturesque sunsets in the UK to "Saharan dust," which is expected to cover parts of the country later this week. Photo by Trevor Rickard, Wikimedia commons.