September weather forecast and climate
Annapolis, MD

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
September, the first month of the autumn, in Annapolis, is still a warm month, with temperature in the range of an average low of 64.6°F (18.1°C) and an average high of 77°F (25°C).

Temperature

In September, the average high-temperature slightly decreases, from 83.3°F (28.5°C) in August, to a still warm 77°F (25°C). The average low-temperature, in September, is 64.6°F (18.1°C).

Humidity

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

Rainfall

In Annapolis, it is raining for 10.5 days, with typically 0.63" (16mm) of accumulated precipitation. Throughout the year, there are 120.4 rainfall days, and 10.47" (266mm) of precipitation is accumulated.

Snowfall

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

Ocean temperature

In Annapolis, in September, the average water temperature is 73.9°F (23.3°C).
Note: For individuals prone to feeling cold, swimming in 73.4°F (23°C) is still regarded as intolerable. A wetsuit is not a necessity, but sunshine, wind, and air temperature are essential factors for relishing swimming at 73.9°F (23.3°C).

Daylight

In September, the average length of the day is 12.4h.

Sunshine

The average sunshine in Annapolis is 9.2h.

UV index

In September, the average daily maximum UV index in Annapolis, Maryland, is 5. A UV Index of 3 to 5 symbolizes a medium vulnerability from the exposure to the Sun's UV radiation for average individuals.
Note: In September, the average maximum UV index of 5 translate into the following recommendations:
Take precautions - Protection against sunburn is recommended. The Sun's most intense and consequently most harmful UV radiation during midday hours should be decreased by minimizing exposure and seeking shade. Sun-protective clothing, a long-sleeved shirt and pants, a wide-brimmed hat, and UVA and UVB-blocking sunglasses are particularly helpful in blocking UV radiation's harmful effects. Beware! The strength of the UV rays is significantly increased by the reflection of the water and sand.

What is the temperature in September in Annapolis?

In September, in Annapolis, Maryland, the average high-temperature is 77°F (25°C), and the average low-temperature is 64.6°F (18.1°C).

What is the average humidity in September in Annapolis?

The average relative humidity in September is 75%.

How much does it rain in Annapolis in September?

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

When it does not snow in Annapolis?

April through October are months without snowfall in Annapolis, Maryland.

What is the water temperature in September in Annapolis?

In Annapolis, in September, the average water temperature is 73.9°F (23.3°C). For individuals prone to feeling cold, swimming in 73.4°F (23°C) is still regarded as intolerable. A wetsuit is not a necessity, but sunshine, wind, and air temperature are essential factors for relishing swimming at 73.9°F (23.3°C).

What is the average length of the day in September in Annapolis?

In September, the average length of the day in Annapolis is 12.4h.

How many hours of sunshine does Annapolis have in September?

In September, the average sunshine is 9.2h.

What is the UV index intensity in September in Annapolis?

The average daily maximum UV index in September in Annapolis is 5. A UV Index of 3 to 5 symbolizes a medium health risk from the exposure to the Sun's UV radiation.
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: 30.05"

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

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: 75%

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

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: 10.5 days

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: 0"

The month with the highest snowfall is January (0.67").
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: 0 days

The month with the highest number of snowfall days is February (2.5 days).
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: 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: 12.4h

The month with the longest days is June (Average daylight: 14.9h).
The month with the shortest days is December (Average daylight: 9.5h).

  • Average sunshine in September: 9.2h

The month with the most sunshine is July (Average sunshine: 10.8h).
The month with the least sunshine is February (Average sunshine: 5h).

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: 5

Months with the highest UV index are May, June, July and August (UV index 6).
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: 33

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: 6mi

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