Amber and yellow heat health alerts have come into force as parts of the UK endure the fourth widespread heatwave of the year so far. Temperatures are forecast to peak on Wednesday with readings as high as 35C (95F) in the hottest places. Though the heatwave will come to a quick end for many on Thursday, well above-average temperatures in the mid- to high 20s Celsius will persist into the weekend. On Wednesday, the Environment Agency declared an official drought for more than half of England, triggered in part by the summer's unrelenting heat and significant lack of rainfall.