Naples weather in September
In September, Naples has daytime highs averaging 25 °C, nights around 18 °C, with 8.7 wet days, and a sea temperature of 24 °C. Figures are 1991–2020 climate normals.
- 25.3°C Average high
- 17.9°C Average low
- 8.7days Wet days
- 90mm Rainfall
- 24.2°C Sea temperature
- 12h Daylight
Daily temperatures through September
How September develops
Averages for the first, middle and last part of the month, from daily 1991–2020 normals. Chance of rain is the share of years in which that calendar day recorded more than 1 mm.
| Days | Avg high | Avg low | Chance of rain |
|---|---|---|---|
| 1–10 September | 26.7 °C | 19.1 °C | 29 % |
| 11–20 September | 25.5 °C | 18.2 °C | 31 % |
| 21–30 September | 23.8 °C | 16.7 °C | 28 % |
- Average highs fall from 26.7 °C early in September to 23.8 °C by the end of it.
What to expect
| Measure | Typical September | Share of the month |
|---|---|---|
| Days above 25 °C | 16 of 30 | 52 % |
| Days above 30 °C | 1.4 of 30 | 5 % |
| Days below 0 °C | 0 of 30 | 0 % |
| Days with more than 1 mm rain | 8.7 of 30 | 29 % |
Conditions in September
| Measure | Average |
|---|---|
| Mean temperature | 22 °C |
| Record high (1991–2020) | 34 °C |
| Record low (1991–2020) | 10 °C |
| Relative humidity | 73 % |
| Wind speed | 13 km/h |
| Cloud cover | 41 % |
Where Naples ranks in September
| Ranking | Position | Value |
|---|---|---|
| Warmest sea temperatures in Europe in September | 18th of 50 | 24 °C |
| Best beach destinations in Europe in September | 23rd of 50 | 85/100 |
| The warmest places in Europe in September | 36th of 50 | 25 °C |
September compared with the months around it
| Month | Avg high | Rainfall | Cloud |
|---|---|---|---|
| July | 28.9 °C | 19 mm | 20 % |
| August | 29.5 °C | 23 mm | 22 % |
| September | 25.3 °C | 90 mm | 41 % |
| October | 21.2 °C | 134 mm | 50 % |
| November | 16.7 °C | 174 mm | 58 % |
See all twelve months for Naples
- September is the 4th warmest month here.
- It is the 5th driest month of the year.
- It ranks 4th for least cloud cover.
- Days last about 12 hours from sunrise to sunset.
- It rains on 8.7 of 30 days — 29 % of the month.
- Nights are about 7.4 °C cooler than the middle of the day.
- The hottest September day on record since 1991 reached 34 °C, 8.7 °C above the usual daytime high.
- Beach score: 85 / 100 — see how this is calculated.
QuestionsSeptember in Naples, answered
How warm is Naples in September?
Daily highs average 25 °C and nights fall to about 18 °C, a spread of 7.4 °C between afternoon and dawn. That makes September the 4th warmest month of the year here.
Does it rain much in Naples in September?
September averages 90 mm of rain, spread over about 9 of the 30 days — 29 % of the month. Cloud cover averages 41 % of the sky.
Is the sea warm enough to swim in September?
The sea averages 24 °C off Naples in September. Most people find water below 20 °C bracing and above 25 °C comfortable for a long swim; this figure is a monthly surface average, so a sheltered bay on a still afternoon can be warmer.
How long are the days in September?
Naples averages 12 hours between sunrise and sunset in September. Day length is computed from latitude and date, so it is exact rather than modelled — but it says nothing about how much of that time is sunny.
Data sources and method
- ERA5 / ERA5-Land reanalysis — Copernicus Climate Change Service (C3S), ECMWF. Copernicus Licence
- Open-Meteo — Open-Meteo.com. CC BY 4.0
- NOAA OISST v2.1 — NOAA Physical Sciences Laboratory. Public domain
- GeoNames — GeoNames.org. CC BY 4.0
- Normal period
- 1991–2020
- Dataset version
- era5-1991-2020-scores1.1
- Last processed
Measured values come from ERA5 reanalysis and are reproduced unchanged. Calculated by us: daylight hours, beach and comfort scores, monthly rankings, threshold day counts, chance of a wet day by date, ten-day averages within the month. Full formulas are on the methodology page.
Contains modified Copernicus Climate Change Service information 2026. Neither the European Commission nor ECMWF is responsible for any use that may be made of the Copernicus information or data it contains.