September weather forecast
Annapolis, MD

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The Chesapeake Bay at dusk, in Annapolis, Maryland, with a distant view of the US Naval Academy chapel dome
The Chesapeake Bay at dusk, in Annapolis, Maryland, with a distant view of the US Naval Academy chapel dome

Weather in September

September sees Annapolis transitioning from summer into fall. The cooling trend starts, presenting an ideal scenario for those seeking milder temperatures. Autumnal colors begin to paint the cityscape against a backdrop of reduced rainfall, now averaging at 0.63" (16mm). September is characterized by its mild climate, less humidity, and fewer crowds, making it a favorable month for visitors.

Temperature

During the shift to September, a minor reduction in average high-temperature is observed, shifting from a moderately hot 83.3°F (28.5°C) in August to a still warm 77°F (25°C). Annapolis in September anticipates an average nighttime temperature of 64.6°F (18.1°C).

Humidity

In Annapolis, Maryland, the average relative humidity in September is 75%.

Rainfall

In Annapolis, in September, during 10.5 rainfall days, 0.63" (16mm) of precipitation is typically accumulated. In Annapolis, during the entire year, the rain falls for 120.4 days and collects up to 10.47" (266mm) of precipitation.

Snowfall

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

Ocean temperature

In September, the average ocean temperature is 73.9°F (23.3°C).
Note: Swimming in 73.9°F (23.3°C) waters may not appeal to those sensitive to cold. Yet, the presence of sunshine, the strength of the wind, and the air temperature can alter this experience. Some might even opt for a wetsuit for added comfort.

Daylight

In September, the average length of the day is 12h and 26min.
On the first day of the month, sunrise is at 6:35 am and sunset at 7:36 pm. On the last day of September, sunrise is at 7:01 am and sunset at 6:49 pm EDT.

Sunshine

In September, the average sunshine is 9.2h.

UV index

In Annapolis, the average daily maximum UV index in September is 5. A UV Index estimate of 3 to 5 represents a medium health hazard from exposure to the Sun's UV radiation for the average person.
Note: A maximum UV index of 5 in September translates into the following recommendations:
Prioritize safety - The need to safeguard skin and eyes from harm is emphasized. Considering the harmful UV rays from the Sun during midday, it's essential to reduce exposure. By wearing a generously brimmed hat, you can cut UV radiation exposure significantly. Warning! The Sun's UV rays intensify with reflections from sand and water.

Frequently asked questions

What is the temperature in September?

The average high-temperature, in September, in Annapolis, is 77°F (25°C), while the average low-temperature is 64.6°F (18.1°C). In August, the average heat index (a.k.a. 'real feel', 'apparent temperature'), which represents the influence of relative humidity on air temperature, is evaluated at 89.6°F (32°C).

What is the average humidity in September?

The average relative humidity in September is 75%.

How much does it rain in September?

In Annapolis, in September, it is raining for 10.5 days, with typically 0.63" (16mm) of accumulated precipitation.

When it does not snow?

April through October are months without snowfall.

What is the ocean temperature in September?

In September, the average ocean temperature is 73.9°F (23.3°C). Depending on a person's sensitivity to cold, with regards to sunshine, wind, and air temperature, a quick swim in 73.9°F (23.3°C) water may be enjoyable.

How many hours of daylight does Annapolis have in September?

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

When is the sunrise / sunset in September?

On the first day of September, sunrise is at 6:35 am and sunset at 7:36 pm. On the last day of the month, sunrise is at 7:01 am and sunset at 6:49 pm EDT.

How long on average sun shines in September?

In Annapolis, the average sunshine duration in September is 9.2h.

What is the UV index reading in September?

In Annapolis, the average daily maximum UV index in September is 5. A UV Index value of 3 to 5 symbolizes a moderate vulnerability 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
Annapolis, MD

Average temperature in September - Annapolis, MD
  • Average high temperature in September: 77°F

The warmest month (with the highest average high temperature) is July (84.7°F).
The month with the lowest average high temperature is January (40.3°F).

  • Average low temperature in September: 64.6°F

The month with the highest average low temperature is July (72°F).
The coldest month (with the lowest average low temperature) is January (29.8°F).

Average pressure in September
Annapolis, MD

Average pressure in September - Annapolis, MD
  • Average pressure in September: 30.05"Hg

The month with the highest atmospheric pressure is November (30.13"Hg).
The month with the lowest atmospheric pressure is June (29.94"Hg).

Average wind speed in September
Annapolis, MD

Average wind speed in September - Annapolis, MD
  • Average wind speed in September: 7.6mph

The windiest month (with the highest average wind speed) is January (10mph).
The calmest months (with the lowest average wind speed) are July and August (6.6mph).

Average humidity in September
Annapolis, MD

Average humidity in September - Annapolis, MD
  • Average humidity in September: 75%

The month with the highest relative humidity is May (78%).
The months with the lowest relative humidity are January, March, April and November (72%).

Average rainfall in September
Annapolis, MD

Average rainfall in September - Annapolis, MD
  • Average rainfall in September: 0.63"

The wettest month (with the highest rainfall) is August (1.69").
The driest month (with the least rainfall) is January (0.47").

Average rainfall days in September
Annapolis, MD

Average rainfall days in September - Annapolis, MD
  • Average rainfall days in September: 10.5 days

The months with the highest number of rainy days are July and August (14.3 days).
The month with the least rainy days is November (5.3 days).

Average snowfall in September
Annapolis, MD

Average snowfall in September - Annapolis, MD
  • Average snowfall in September: 0"

The month with the highest snowfall is January (0.67").
The months with the least snowfall are April, May, June, July, August, September and October (0").

Average snowfall days in September
Annapolis, MD

Average snowfall days in September - Annapolis, MD
  • Average snowfall days in September: 0 days

The month with the highest number of snowfall days is February (2.5 days).
The months with the least snowfall days are May, June, July, August, September and October (0 days).

Average sea temperature in September
Annapolis, MD

Average sea temperature in September - Annapolis, MD
  • Average sea temperature in September: 73.9°F

The best month for swimming (with the highest average sea temperature) is August (77.8°F).
The coldest month (with the lowest average sea temperature) is February (45.1°F).

Average daylight in September /
Average sunshine in September
Annapolis, MD

Average daylight in September / Average sunshine in September - Annapolis, MD
  • 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 30min).

  • Average sunshine in September: 9h and 1min

The month with the most sunshine is July (Average sunshine: 10h and 48min).
The month with the least sunshine is February (Average sunshine: 5h and 0min).

Average sunshine days in September
Annapolis, MD

Average sunshine days in September - Annapolis, MD
  • Average sunshine days in September: 17.4 days

The month with the most sunshine days is November (23.4 days).
The month with the least sunshine days is August (13.8 days).

Average UV index in September
Annapolis, MD

Average UV index in September - Annapolis, MD
  • 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, February and December (UV index 2).

Average cloud cover in September
Annapolis, MD

Average cloud cover in September - Annapolis, MD
  • Average cloud cover in September: 33

The months with the most cloud cover are February and March (Cloud cover 45).
The month with the least cloud cover is July (Cloud cover 28).

Average visibility in September
Annapolis, MD

Average visibility in September - Annapolis, MD
  • 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).

Annapolis, Maryland, USA

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