Summers are warm to hot and sunny with average daytime maximum temperatures of . Summer warmth can linger well into October. The weather in the winter is generally mild by European standards, managing around 6 hours of sunshine each day, with temperatures averaging around in the coldest month. The city receives most of its rainfall over the winter; rain is scarce between June and September. The annual average temperature is around 17.5 to 18.5 °C and the annual rainfall is around . The average sea temperature is in January rising to in August and September. Higher sea water temperatures are reached if the weather patterns produce a significant outflow of warmer surface water out of the Mediterranean which bathe the coastal Algarve with much warmer water.