September weather forecast
Claymont, DE

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Weather in September

September marks the transition from summer to fall in Claymont. Temperatures start to fall, with highs of 76.3°F (24.6°C) and lows reaching down to 59.9°F (15.5°C). September sees the most sunshine hours with an average of 8.8 hours per day, against a declining daylight duration of 12.4 hours. Although rainfall decreases significantly to 2.4" (61mm), the city's climate retains its humidity. The balance between humidity, pleasant temperatures, and ample sunshine makes September a popular month among residents.

Temperature

A subtle change in temperatures is noted as August gives way to September, with average highs reducing from a moderately hot 82.9°F (28.3°C) to a still warm 76.3°F (24.6°C). The low-temperature averages to a moderate 59.9°F (15.5°C) during the nights of September.

Humidity

In September, the average relative humidity is 77%.

Rainfall

In Claymont, in September, it is raining for 13.3 days, with typically 2.4" (61mm) of accumulated precipitation. Throughout the year, there are 168.9 rainfall days, and 35.55" (903mm) of precipitation is accumulated.

Snowfall

June through September are months without snowfall.

Daylight

In September, the average length of the day is 12h and 26min.
On the first day of September, sunrise is at 6:30 am and sunset at 7:32 pm. On the last day of the month, sunrise is at 6:57 am and sunset at 6:45 pm EDT.

Sunshine

In September, the average sunshine is 8.8h.

UV index

In September, the average daily maximum UV index is 4. A UV Index value of 3 to 5 symbolizes a moderate health risk from unsafe exposure to UV radiation for the ordinary person.
Note: During September, 4 as the daily maximum UV index converts into the following advice:
Ensure safety - Imperative it is to shield skin and eyes from damage. The Sun is most powerful around mid-day, so it's a good practice to reduce direct exposure. For excellent sun protection for the eyes, ears, face, and neck, consider a wide-brim hat.

Frequently asked questions

What are September temperatures?

September temperatures vary between a high-temperature of 76.3°F (24.6°C) and a low-temperature of 59.9°F (15.5°C). In August, the average heat index (a.k.a. 'felt air temperature', 'real feel'), which represents the influence of relative humidity on air temperature, is estimated at 89.6°F (32°C).

What is the average humidity in September?

The average relative humidity in September is 77%.

How many days does it rain in September?

In Claymont, in September, it is raining for 13.3 days, with typically 2.4" (61mm) of accumulated precipitation.

When it does not snow?

In Claymont, snow does not fall in June through September.

Does it snow in September?

In Claymont, in September, it doesn't snow. In October, it regularly snows.

How many hours of daylight does Claymont have in September?

The average day length in September is 12h and 26min.

What time are sunrise and sunset in September?

On the first day of September, sunrise is at 6:30 am and sunset at 7:32 pm. On the last day of the month, sunrise is at 6:57 am and sunset at 6:45 pm EDT.

How many hours of sunshine does Claymont have in September?

In September, the average sunshine duration is 8.8h.

How high is the UV index in September?

The average daily maximum UV index in September is 4. A UV Index value of 3 to 5 symbolizes a medium hazard to health from unprotected exposure to UV radiation.
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
Claymont, DE

Average temperature in September - Claymont, DE
  • Average high temperature in September: 76.3°F

The warmest month (with the highest average high temperature) is July (84.9°F).
The month with the lowest average high temperature is January (37°F).

  • Average low temperature in September: 59.9°F

The month with the highest average low temperature is July (68.4°F).
The coldest month (with the lowest average low temperature) is January (25.3°F).

Average pressure in September
Claymont, DE

Average pressure in September - Claymont, DE
  • Average pressure in September: 30.05"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
Claymont, DE

Average wind speed in September - Claymont, DE
  • Average wind speed in September: 5.8mph

The windiest months (with the highest average wind speed) are January, February and March (8.6mph).
The calmest month (with the lowest average wind speed) is August (5.4mph).

Average humidity in September
Claymont, DE

Average humidity in September - Claymont, DE
  • Average humidity in September: 77%

The month with the highest relative humidity is October (78%).
The month with the lowest relative humidity is April (72%).

Average rainfall in September
Claymont, DE

Average rainfall in September - Claymont, DE
  • Average rainfall in September: 2.4"

The wettest month (with the highest rainfall) is August (4.09").
The driest month (with the least rainfall) is January (2.36").

Average rainfall days in September
Claymont, DE

Average rainfall days in September - Claymont, DE
  • Average rainfall days in September: 13.3 days

The month with the highest number of rainy days is May (18.7 days).
The month with the least rainy days is November (8.8 days).

Average snowfall in September
Claymont, DE

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

The month with the highest snowfall is March (3.58").
The months with the least snowfall are June, July, August and September (0").

Average snowfall days in September
Claymont, DE

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

The month with the highest number of snowfall days is January (6.8 days).
The months with the least snowfall days are June, July, August and September (0 days).

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

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

The month with the longest days is June (Average daylight: 14h and 54min).
The month with the shortest days is December (Average daylight: 9h and 24min).

  • Average sunshine in September: 8h and 5min

The month with the most sunshine is July (Average sunshine: 10h and 36min).
The month with the least sunshine is February (Average sunshine: 4h and 54min).

Average sunshine days in September
Claymont, DE

Average sunshine days in September - Claymont, DE
  • Average sunshine days in September: 14.2 days

The month with the most sunshine days is November (18.6 days).
The months with the least sunshine days are May and July (9.8 days).

Average UV index in September
Claymont, DE

Average UV index in September - Claymont, DE
  • Average UV index in September: 4

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, February, November and December (UV index 2).

Average cloud cover in September
Claymont, DE

Average cloud cover in September - Claymont, DE
  • Average cloud cover in September: 37

The months with the most cloud cover are February and March (Cloud cover 47).
The month with the least cloud cover is July (Cloud cover 31).

Average visibility in September
Claymont, DE

Average visibility in September - Claymont, 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).

Claymont, Delaware, USA

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