The UK is experiencing a heatwave, with temperatures reaching the mid-30s in places. One report says Monday recorded a highest temperature of 34°C, indicating unusually warm conditions for the time of year. Other coverage focuses on how warm it may become later in the week and how long the hot weather is expected to last. According to the information provided, temperatures are forecast to rise further by the end of the week, suggesting the heatwave continues rather than easing immediately. The reports do not provide additional detailed breakdowns of regional differences, rainfall changes, or specific end dates within the excerpt supplied. Overall, the sources agree that the current spell of hot weather persists across multiple days, and that the upper end of the temperature range is expected to occur later in the week.