Well done Porthmadog. Officially the hottest place in the UK. Temperatures in North Wales reached new heights on Sunday, with Porthmadog reaching 27.8°C, according to the Met Office. That makes North Wales hotter than Barcelona, Monaco and Lisbon. Although the Met Office, is being cautious about a super hot summer saying advanced predictions are generally unreliable, others are forecasting this summer will be a cracker.