May weather forecast
Lisbon, Portugal

The arrival of May marks the onset of the city’s summer season. Despite the rainfall decreasing to 54mm (2.13") in May, sporadic showers continue to maintain Lisbon’s lush landscapes. Gradually, the city begins to warm up with temperature highs moving past the 20°C (68°F) mark. This is a time when locals and visitors can enjoy the city’s beaches, although the sea temperature remains a bit on the cooler side. Longer daylight hours combined with a high UV index promise gloriously sunny days, perfect for sightseeing and outdoor activities.

Temperature

The ushering in of May in Lisbon brings an average high-temperature of an agreeable 22.1°C (71.8°F), closely mirroring the 19.8°C (67.6°F) of April. In the month of May, Lisbon records a consistent average low-temperature of 13.9°C (57°F).

Rainfall

In Lisbon, during May, the rain falls for 8 days and regularly aggregates up to 54mm (2.13") of precipitation. In Lisbon, during the entire year, the rain falls for 112 days and collects up to 774mm (30.47") of precipitation.

Sea temperature

In May, the average sea temperature in Lisbon is 17.4°C (63.3°F).
Note: In water of 17.4°C (63.3°F), the majority of people do not enjoy swimming. Breathing becomes increasingly hard to manage as the temperature drops from 21°C (69.8°F) to 15°C (59°F).

Daylight

The average length of the day in May is 14h and 18min.
On the first day of the month, sunrise is at 06:38 and sunset at 20:28. On the last day of May, in Lisbon, sunrise is at 06:13 and sunset at 20:55 WEST.

Sunshine

In May, the average sunshine is 9h.

UV index

In May, the average daily maximum UV index in Lisbon, Portugal, is 8. A UV Index value of 8 to 10 symbolizes a very high health risk from exposure to the Sun's UV radiation for ordinary individuals.
Note: In May, the maximum UV index of 8 suggests this advice:
Take special precautions, as unprotected eyes and skin can be burned and damaged quickly. To the best of your ability, limit your exposure to the sun between the hours of 10 a.m. and 4 p.m., when UV radiation is at its peak. Consider a wide-brim hat essential for effective sun defense covering your face, neck, and eyes.