Average September Weather in Rhode Island

Typical temperatures, precipitation, humidity and sunshine during September at cities and towns throughout Rhode Island are listed below.

Temperatures in Rhode Island for September

This table gives the averages in degrees Fahrenheit and Celsius for maximum and minimum monthly temperatures. These normal temperatures are based on weather data collected from 1991 to 2020 for the US National Centers for Environmental Information.

Precipitation in Rhode Island for September

Here are the September averages for rainfall in Rhode Island. Each place has a total for how many days of wet weather it usually gets this month and for the normal amount of precipitation, based on the weather during 1991 to 2020. The calculation of days only includes those when precipitation totalled 0.01 inches (0.25 millimetres) or more.

Sunshine in Rhode Island for September

In the table below, the average number of Sunny Days in Rhode Island is the total days this month when the sky is mostly clear. This includes the days when cloud covers up to 30% of the sky during daylight hours.

Partly Sunny Days have cloud covering from 40% to 70% of the sky during the daytime. The rest of the days during September are mainly overcast, with at least 80% cloud cover. Total Days With Sun is a sum of the Sunny plus Partly Sunny days.

Humidity in Rhode Island

In the table below, the Daily number is the average of relative humidity readings taken every three hours throughout the day. Morning percentages are for 7 am and Afternoon levels are for 4 pm local standard time. All the humidity numbers are averages for the years 1961 to 1990.