Average September Weather in Delaware

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

Temperatures in Delaware 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.

Average September temperatures
High °F Low °F Place High °C Low °C
79 61 Dover 26 16
80 61 Georgetown 26 16
79 58 Greenwood 26 14
80 64 Lewes 26 18
79 58 Newark 26 15
79 59 Wilmington 26 15

Precipitation in Delaware for September

Here are the September averages for rainfall in Delaware. 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.

Average precipitation in September
Days Place Inches Milli­metres
8 Dover 4.3 108
12 Georgetown 4.5 115
8 Greenwood 4.8 121
9 Lewes 4.5 114
8 Newark 4.9 124
9 Wilmington 4.4 111

Sunshine in Delaware for September

In the table below, the average number of Sunny Days in Delaware 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. These numbers are averages of most the years the weather station has operated.

Days of sunshine in September
City Sunny Partly Sunny Total Days
With Sun
Wilmington 10 8 18

Humidity in Delaware

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.

Average September humidity (%)
Daily City Morning Afternoon
72 Wilmington 84 55
References

National Climatic Data Center. Comparative Climatic Data.

NOAA National Centers for Environmental Information (NCEI). Climate Normals.

World Data Center for Meteorology. Climate of the World.

More Delaware Weather Information

Delaware Weather
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