September weather forecast
Nassau, DE

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Weather in September

The first month of the autumn, September, is still a warm month in Nassau, Delaware, with an average temperature varying between 67.3°F (19.6°C) and 74.1°F (23.4°C).

Temperature

A mild drop in Nassau's average high-temperature is observed in September, transitioning from a warm 79.5°F (26.4°C) in August to a still moderately hot 74.1°F (23.4°C). Nassau indicates a consistently low-temperature of 67.3°F (19.6°C) during the nights of September.

Humidity

In September, the average relative humidity in Nassau is 78%.

Rainfall

In Nassau, in September, during 14.8 rainfall days, 2.68" (68mm) of precipitation is typically accumulated. Throughout the year, there are 173.6 rainfall days, and 36.97" (939mm) of precipitation is accumulated.

Snowfall

April through October are months without snowfall.

Daylight

In Nassau, the average length of the day in September is 12h and 26min.
On the first day of September in Nassau, sunrise is at 6:30 am and sunset at 7:30 pm. On the last day of the month, sunrise is at 6:56 am and sunset at 6:44 pm EDT.

Sunshine

The average sunshine in September is 9.6h.

UV index

In Nassau, the average daily maximum UV index in September is 5. A UV Index value of 3 to 5 symbolizes a medium health hazard from unprotected exposure to Sun's UV rays for the average person.
Note: The maximum UV index of 5 during September leads to these instructions:
Exercise prevention - Protecting skin and eyes from harm is required. Solar radiation is at its peak intensity during midday, so it's advisable to stay indoors or in the shade. Sunglasses that ward off UVA and UVB rays play a pivotal role in reducing solar eye damage.
Updated: Feb 10, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What is the average September temperature in Nassau?

During September, Nassau experiences an average high-temperature of 74.1°F (23.4°C) and a low-temperature of 67.3°F (19.6°C). In July, the average heat index (a.k.a. 'real feel', 'apparent temperature'), which factors the actual air temperature with the relative humidity, is appraised at 86°F (30°C).

What is the average humidity in September in Nassau?

In September, the average relative humidity in Nassau, Delaware, is 78%.

How much does it rain in Nassau in September?

In Nassau, Delaware, during September, the rain falls for 14.8 days and regularly aggregates up to 2.68" (68mm) of precipitation.

When it does not snow in Nassau?

In Nassau, snow does not fall in April through October.

How many hours of daylight does Nassau have in September?

In September, the average day length in Nassau is 12h and 26min.

When is the sunrise / sunset in September in Nassau?

On the first day of September in Nassau, sunrise is at 6:30 am and sunset at 7:30 pm. On the last day of the month, sunrise is at 6:56 am and sunset at 6:44 pm EDT.

How many hours of sunshine does Nassau have in September?

The average sunshine duration in September in Nassau is 9.6h.

What is the UV index intensity in September in Nassau?

The average daily maximum UV index in September is 5. A UV Index estimate of 3 to 5 represents a medium hazard to health from unsafe exposure to Sun's UV rays.
Average humidity
Average rainfall days
Average snowfall
Average snowfall days
Average daylight
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in September
Nassau, DE

Average temperature in September - Nassau, DE
  • Average high temperature in September: 74.1°F

The warmest month (with the highest average high temperature) is July (80.6°F).
The month with the lowest average high temperature is January (41.2°F).

  • Average low temperature in September: 67.3°F

The month with the highest average low temperature is July (73°F).
The coldest month (with the lowest average low temperature) is January (32°F).

Average pressure in September
Nassau, DE

Average pressure in September - Nassau, DE
  • Average pressure in September: 30.04"Hg

The month with the highest atmospheric pressure is November (30.12"Hg).
The month with the lowest atmospheric pressure is June (29.94"Hg).

Average wind speed in September
Nassau, DE

Average wind speed in September - Nassau, DE
  • Average wind speed in September: 9.9mph

The windiest month (with the highest average wind speed) is January (12.5mph).
The calmest month (with the lowest average wind speed) is August (8.3mph).

Average humidity in September
Nassau, DE

Average humidity in September - Nassau, DE
  • Average humidity in September: 78%

The month with the highest relative humidity is May (81%).
The month with the lowest relative humidity is November (73%).

Average rainfall in September
Nassau, DE

Average rainfall in September - Nassau, DE
  • Average rainfall in September: 2.68"

The wettest month (with the highest rainfall) is August (4.13").
The driest month (with the least rainfall) is January (2.2").

Average rainfall days in September
Nassau, DE

Average rainfall days in September - Nassau, DE
  • Average rainfall days in September: 14.8 days

The month with the highest number of rainy days is July (18.6 days).
The month with the least rainy days is January (9.6 days).

Average snowfall in September
Nassau, DE

Average snowfall in September - Nassau, DE
  • Average snowfall in September: 0"

The month with the highest snowfall is January (0.98").
The months with the least snowfall are April, May, June, July, August, September and October (0").

Average snowfall days in September
Nassau, DE

Average snowfall days in September - Nassau, DE
  • Average snowfall days in September: 0 days

The month with the highest number of snowfall days is January (3.7 days).
The months with the least snowfall days are April, May, June, July, August, September and October (0 days).

Average daylight in September /
Average sunshine in September
Nassau, DE

Average daylight in September / Average sunshine in September - Nassau, DE
  • Average daylight in September: 12h and 2min

The month with the longest days is June (Average daylight: 14h and 48min).
The month with the shortest days is December (Average daylight: 9h and 30min).

  • Average sunshine in September: 9h and 4min

The month with the most sunshine is July (Average sunshine: 11h and 0min).
The month with the least sunshine is February (Average sunshine: 5h and 0min).

Average sunshine days in September
Nassau, DE

Average sunshine days in September - Nassau, DE
  • Average sunshine days in September: 12.2 days

The month with the most sunshine days is November (17.6 days).
The month with the least sunshine days is May (9.8 days).

Average UV index in September
Nassau, DE

Average UV index in September - Nassau, DE
  • Average UV index in September: 5

The months with the highest UV index are May, June, July and August (UV index 6).
The months with the lowest UV index are January and December (UV index 2).

Average cloud cover in September
Nassau, DE

Average cloud cover in September - Nassau, DE
  • Average cloud cover in September: 30

The months with the most cloud cover are February and March (Cloud cover 44).
The month with the least cloud cover is July (Cloud cover 26).

Average visibility in September
Nassau, DE

Average visibility in September - Nassau, DE
  • Average visibility in September: 6mi

The months with the highest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
The months with the lowest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).

Nassau, Delaware, USA

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