Average Weather during August in Lisbon (Lisbon Region), Portugal. Lisbon has long hot summers, pleasantly warm springs/autumns and mild, but possibly wet winters. However pay attention to possible thunderstorms that may occur in the evening. The average minimum temperature (usually the minimum temperature is noted during the night) in Lisbon in August is 19.0°C (66.2°F). Lisbon at the End of August August is in the summer in Lisbon and is typically the 2nd warmest month of the year. The mean temperature is 73°F (22.8°C). Lisbon is situated in Mediterranean climate zone that typically has warm or hot summer with mild rains and soft but rainy winter. Daytime maximum temperatures average around a comfortable 28°C (82°F), whilst at night 12°C (54°F) is normal. Search. This is usually the best time to go to the beach to get a tan or swim as the water is relatively warm. Showing: All Year January February March April May June July August September October November December The average maximum temperature lies around 28.0°C (82.4°F). Based on weather reports collected during 1985–2015. August weather forecast for Lisbon, Portugal. Lisbon in the Middle of August. Tourists begin to flock into Lisbon to enjoy the summer festivals and the pleasant weather. August is a dry month with an average of 6mm (0.2in) rain. °F. Temperature (°C) 11.7 12.4 13.8 15.4 17.5 20.1 22.4 22.7 21.6 18.7 Averages are for Lisbon Portela Airport, which is 3 miles from Lisbon. Portugal. however as they disappear discreetly at the same time as the heat, one can still enjoy a magnificent weather in Lisbon throughout August for the rest of the day. The climate in Lisbon during August can be summarized as warm and reasonably dry. Lisbon, Portugal - Travel and vacation weather averages, current conditions and forecasts. January February March April May June July August September October November December; Avg. Weather Atlas: Lisbon, Portugal - August weather forecast and climate information. Lisbon Extended Forecast with high and low temperatures.  The height of the tourist season is from June until the end of September, while the beaches are at their busiest in July and August. Toggle navigation. more about this country The weather is suitable for spending time on Lisbon’s beaches from May until the middle of September. The fogs intensify and persist for hours. Last 2 weeks of weather July and August are the hottest months as the temperatures soar to sometimes 43°C (109°F). The average sea surface temperature in August 2020 for Lisbon was 72.5°F.The maximum and minimum values were 71.2°F and 74.6°F respectively. Almost anything done during August will be pleasurable. To help you choose the best time to travel, you can find climate data below on the weather in Lisbon in August.