Lisbon Climate Trends
Portugal · Europe · 50 years of climate trend data
This page tracks how Lisbon's climate has shifted over 50 years of daily measurements, warmer summers, milder winters, and changes in rainfall, rather than current conditions. The two clearest signs of change: warm summer nights have grown from 4.8 to 9.8 a year and extremely hot days have grown by 4 a year. Measurement period: the last 50 years (1976-2025).
Data through September 13, 2026.
Frequently asked questions about Lisbon's climate
How much warmer have summers in Lisbon become?
The average daytime high across June, July and August rose by 1.2°C between 1976-1980 and 2021-2025. That is a five-year average at each end rather than two isolated summers, so a single exceptional heatwave or cool summer does not drive the number.
Have winters in Lisbon become milder?
The average daytime high across December, January and February rose by 1.2°C between 1976-1980 and 2021-2025. In many capitals in this dataset winter is changing faster than summer, which shows up most clearly in the frost-day count below.
How many days above 30°C does Lisbon get a year?
Lisbon averaged 9 days a year above 30°C in 2021-2025, up from 5 in 1976-1980. These are the days that set peak cooling demand and the days hospitals see heat complaints rise.
How many frost days does Lisbon still get?
Lisbon does not drop below freezing in any year of this record, not in 1976-1980 and not in 2021-2025. Frost is not a useful measure of change here, though the heat figures above are.
Is spring arriving earlier in Lisbon?
Spring now starts about 0.1 weeks earlier than in 1976-1980. The start point is the first day the trailing seven-day average high crosses 12°C, a fixed in-house measure used only to compare Lisbon against itself rather than against other cities.
Has the growing season in Lisbon grown longer?
The growing season here is measured as the stretch between the start of spring and the first autumn night below freezing. Lisbon has no reliable autumn frost in this record, so that measure yields no meaningful number.
Is rainfall in Lisbon getting heavier?
Lisbon averaged 3.8 days a year with more than 20mm of rain in 2021-2025, down from 4 in 1976-1980. This capital gets fewer heavy rain days now, which brings its own problems in a drying climate.
