Parts of the UK are set to be hotter than Hawaii and Athens today, with temperatures expected to hit 27C in London and East Anglia. Forecasters say it could be the hottest day of the year so far, with temperatures running around 10C above average for this time of year. Honolulu is forecast to reach 26C, while Cardiff could even be warmer than Athens. The heat won’t last long though, with rain and thunderstorms expected to move in over the bank holiday weekend.