Weather in Algarve in September

How September compares

September is the 3rd warmest month of the year in Algarve and ranks 71st of 134 destinations we compare for September - see where else is hot in September. Within Portugal it is 5th of 13 (Portugal in September). Against London's average high of 18.6°C in September, Algarve is 7.8°C warmer by day and 7.0°C warmer at night.

Daytime and night-time in September

The typical September day in Algarve peaks at 26.4°C, but that is an average: the warmest 10% of days reach 30.1°C or more. About 66% of days top 25°C and 1 in 8 pass 30°C. Nights average 18.2°C; one night in ten drops to 15.7°C or lower, so pack a layer for evenings. Between 1991 and 2020 the hottest September day here reached 39.4°C (2016-09-05) and the coldest night 11.5°C (1994-09-23).

Rain in September

Some rain (4-8 rainy days): about 4 days with 1 mm or more, 23 mm in total. Year to year it varies a lot - the wettest September was 2008 with 102 mm, the driest 2017 with 0 mm. Humidity averages 67%.

Sea temperature in September

The sea averages 20.6°C - bracing (18-22°c). Depending on the year it ranges from 19.5°C to 22.1°C. For the warmest sea here, come in August (20.7°C).

Sunshine and daylight

Around 8.4 hours of sunshine a day (estimated from cloud cover), 12.2 hours of daylight: the sun rises about 07:14 and sets about 19:40 local time in mid-September. Average cloud cover is 31%.

Is September a good time to visit Algarve?

Yes - it is one of the better months: hot days, manageable rain and long sunny days. The best months for Algarve on our scoring are July, August, June; months averaging 25°C or more: Jun, Jul, Aug, Sep.

Warm days, with some hotter spells

Pack mainly for warm weather, but do not assume every afternoon will feel the same. Temperatures reach 25°C on 66% of days, making September a reasonable bet for sitting outside and spending time at the beach. Days reaching 30°C account for 13%, so hotter spells remain a possibility rather than the everyday expectation. On those days, put more active plans earlier in the day and leave room for shade around midday. Light, breathable clothing is the sensible starting point, with suncream and a hat. If you dislike heat altogether, September may still feel too hot at times.

Plenty of sunshine, but leave room for rain

With about 8.4 hours of sunshine out of 12.2 hours of daylight, September gives you a useful amount of bright weather for outdoor plans. There are about 4 rainy days, so rain is a catch to allow for, not a reason on its own to rule the month out. A light waterproof is more practical than packing only beach clothes, and it helps to keep outdoor plans movable. The averages cannot promise a dry stay or tell you when showers will arrive. This is a good fit if you are happy to adjust your day rather than need uninterrupted sunshine.

Beach weather does not mean warm water

The air is warm enough to make beach time appealing, but the sea deserves a separate judgement. Its average temperature is 20.6°C, with a year-to-year range of 20°C to 22°C. That puts it in bracing territory: inviting enough for travellers who enjoy cooler water, less convincing if a comfortably warm swim is central to the holiday. Plan around how you actually like to swim, rather than assuming warm afternoons mean warm water. If you prefer a quick dip followed by time out of the sea, September makes more sense than it does for someone who wants to linger in warm water.