average september temps in lisbon
Lisbon: Annual Weather Averages. July is the hottest month in Lisbon with an average temperature of 24Â°C (74Â°F) and the coldest is January at 11Â°C (52Â°F) with the most daily sunshine hours at 9 in May. The wettest month is November with an average of 127.6mm of rain. The best month to swim in the sea is in September when the average sea temperature is 20Â°C (68Â°F).