September weather forecast
Cascais, Portugal

Cascais in September boasts slightly milder weather than August while maintaining the city's attractive summer charm. Remaining dry but starting to exhibit the subtle signs of fall, the rainfall increases to 31mm (1.22"). The weather favors outdoor enthusiasts with its still comfortably warm temperatures and gentle sea breezes. As October lures closer, the number of hours of sunshine decline, as does the UV index, signaling the slow retreat from summer.

Temperature

Cascais's shift into September is marked by a subtle change to a still moderately hot 26°C (78.8°F) from August's 27°C (80.6°F) in temperature. In Cascais, an average nighttime temperature of 17°C (62.6°F) is expected during September.

Rainfall

In Cascais, Portugal, in September, it is raining for 6 days, with typically 31mm (1.22") of accumulated precipitation. In Cascais, Portugal, during the entire year, the rain falls for 116 days and collects up to 841mm (33.11") of precipitation.

Sea temperature

September is the month with the warmest seawater in Cascais, with an average sea temperature of 19.9°C (67.8°F).
Note: For the majority, swimming in 19.9°C (67.8°F) does not offer a pleasant experience. Below 21°C (69.8°F), the difficulty in controlling breathing escalates.

Daylight

The average length of the day in September in Cascais is 12h and 26min.
On the first day of September, sunrise is at 07:07 and sunset at 20:07. On the last day of the month, sunrise is at 07:33 and sunset at 19:21 WEST.

Sunshine

The average sunshine in September in Cascais is 8h.

UV index

In Cascais, Portugal, the average daily maximum UV index in September is 6. A UV Index of 6 to 7 symbolizes a high health hazard from unsafe exposure to UV radiation for the average person.
Note: In September, an average UV index of 6 transforms into the following instructions:
Avert overexposure. Light-skinned people might experience burning in less than 20 minutes. Try to minimize direct Sun exposure between 10 a.m. and 4 p.m., the peak period for UV radiation. Also note that objects like parasols or canopies might not provide complete sun protection. Sun-protective clothing, a long-sleeved shirt and pants, a wide-brimmed hat, and UVA and UVB-blocking sunglasses are particularly helpful in blocking UV radiation's harmful effects.