Southampton is typically mild in September.

Maximum temperatures go down compared to the previous month from +21°C to +19°C. The minimum temperature also goes down from +13°C to +11°C.

Pack a light jacket as it will be warm in the day and cool in the evenings.

September is one of the warmest months in Southampton, here is the comparison with other months:

September weather is still as ok as in August. It’s getting colder in September. From +21°C in the day, the average maximum temperature lowers to +19°C. As September arrives, the amount of rainfall goes down. On average, the rainfall volume decreases from 62 mm to 60 mm. Humidity rises from 79% to 82%. The average wind speed doesn’t change much during September, staying around 3 m/s. The amount of sunny days stay about the same, averaging 4 sunny days during the month.

October brings much the same weather, it remains ok.

The climate in Southampton in September has not changed much over the last 43 years.

The average temperature was the lowest in 1979 (+12°C) and the highest in 2022 (+16°C). The driest year was 1990 with only 529 mm of rainfall, and the wettest year was 2020 with 1617 mm.

For this page, we’ve looked at the typical weather in Southampton, based on historical hourly weather data from January 1, 1979, to December 31, 2023.

For past dates, we show actual recorded data at the location at that time. Forecasts are based on recorded weather during that day of the year, averaged over the total years for which we have records (unless stated otherwise). The daily temperature is the highest recorded temperature in the shadow during that day.