Weather in Naples in September

How September compares

September is the 4th warmest month of the year in Naples and ranks 89th of 134 destinations we compare for September - see where else is hot in September. Within Italy it is 4th of 16 (Italy in September). Against London's average high of 18.6°C in September, Naples is 6.7°C warmer by day and 6.8°C warmer at night.

Daytime and night-time in September

The typical September day in Naples peaks at 25.3°C, but that is an average: the warmest 10% of days reach 28.9°C or more. About 53% of days top 25°C and 1 in 20 pass 30°C. Nights average 18.0°C; one night in ten drops to 15.0°C or lower, so pack a layer for evenings. Between 1991 and 2020 the hottest September day here reached 34.0°C (2020-09-13) and the coldest night 10.2°C (2017-09-21).

Rain in September

Wet (more than 8 rainy days): about 9 days with 1 mm or more, 90 mm in total. Year to year it varies a lot - the wettest September was 1996 with 253 mm, the driest 1997 with 15 mm. Humidity averages 73%.

Sea temperature in September

The sea averages 24.4°C - warm enough to swim (22°c+). Depending on the year it ranges from 23.6°C to 25.3°C. For the warmest sea here, come in August (26.4°C).

Sunshine and daylight

Around 7.3 hours of sunshine a day (estimated from cloud cover), 12.2 hours of daylight: the sun rises about 06:44 and sets about 19:13 local time in mid-September. Average cloud cover is 41%.

Is September a good time to visit Naples?

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

Warm days without consistently intense heat

Naples in September suits travellers who want warmth without making very hot weather the main feature of their holiday. Days reach 25°C around 53% of the time, but only 5% reach 30°C, so strong heat is possible rather than routine. Humidity averages 73%, which can make warmer spells feel sticky; breathable clothes and a slower pace at midday are sensible. Evenings are usually mild enough that heavy layers would be unnecessary, though the coldest 10% of nights fall to 15°C or below. Pack a light jumper or jacket for sitting outside after dark, alongside your daytime summer clothes.

Good swimming weather, with room for rain

The sea is a stronger reason to choose September than any promise of uninterrupted sunshine. At an average 24.4°C, it is warm enough for swimming, though rain may change when you want to go. Expect about 9 rainy days, so a waterproof layer and plans you can rearrange are more useful than assuming every day will stay dry. There are about 7.3 hours of sunshine within 12.2 hours of daylight: plenty of scope for time outdoors, but not constant clear skies. This is a good fit if you are happy to choose swimming and longer outdoor stretches around the weather. It is less suitable if even occasional wet days would spoil the trip.