Annapolis
Maryland, USA
Long-term weather forecast
Long-term weather forecast

September weather forecast and climate
Annapolis, MD

A view of Chesapeake Bay at dusk, in Annapolis, Maryland, with a distant view of the US Naval Academy chapel dome
A view of 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 average temperature varying between 62.8°F (17.1°C) and 76.8°F (24.9°C).

Temperature

In Annapolis, the average high-temperature slightly decreases, from 84°F (28.9°C) in August, to a still moderately hot 76.8°F (24.9°C). In September, in Annapolis, the average low-temperature is 62.8°F (17.1°C).

Rainfall

The month with the most rainfall in Annapolis is September when the rain falls for 7.8 days and typically aggregates up to 4.8" (120.9mm) of precipitation.

Ocean temperature

In Annapolis, the average seawater temperature is 73.9°F (23.3°C). A person's cold intolerance, with sunshine, wind, and air temperature, are essential factors for enjoying swimming in 73.9°F (23.3°C) water. (FYI: The Olympic swimming competition requires a water temperature between 77°F (25°C) and 82.4°F (28°C).)

Daylight

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

Sunshine

In September, the average sunshine is 8h.

UV index

The average daily maximum UV index in September is 7. A UV Index of 6 to 7 symbolizes a high health hazard from unprotected exposure to the Sun's UV rays for the average person.
In September, the average maximum UV index of 7 translate into the following recommendations:
Take precautions and utilize sun safety practices. Protection against the skin and eye damage is required. The Sun's UV radiation is most powerful between 10 a.m. and 4 p.m. To the extent possible, limit exposure to the direct sun during these hours. On bright days sunglasses that block both UVA and UVB rays should be worn. A hat with a wide brim is extremely helpful, as it can prevent roughly 50% of UV radiation from reaching the eyes. 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, the average high-temperature is 76.8°F (24.9°C), and the average low-temperature is 62.8°F (17.1°C).

How many days does it rain in September in Annapolis?

In September, the rain falls for 7.8 days. Throughout September, 4.8" (120.9mm) of precipitation is accumulated.

What is the wettest month in Annapolis?

September is the month with the most rainfall in Annapolis, Maryland. Rain falls for 7.8 days and accumulates 4.8" (120.9mm) of precipitation.

What is the ocean temperature in September in Annapolis?

In Annapolis, Maryland, in September, the average water 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?

The average length of the day in September is 12.4h.

How many hours of sunshine does Annapolis have in September?

In September, the average sunshine in Annapolis is 8h.

What is the UV index reading in September in Annapolis?

In Annapolis, Maryland, the average daily maximum UV index in September is 7. A UV Index of 6 to 7 symbolizes a high health risk from unprotected exposure to the UV radiation.
Average temperature in September - Annapolis, MD
  • Average high temperature in September: 76.9°F

The warmest month (with the highest average high temperature) is July (85.8°F).
The month with the lowest average high temperature is January (42.7°F).

  • Average low temperature in September: 62.8°F

The month with the highest average low temperature is July (71.2°F).
The coldest month (with the lowest average low temperature) is January (29.1°F).

Average rainfall in September - Annapolis, MD
  • Average rainfall in September: 4.8"

The wettest month (with the highest rainfall) is September (4.8").
The driest month (with the lowest rainfall) is February (2.9").

Average rainfall days in September - Annapolis, MD
  • Average rainfall days in September: 7.8 days

Months with the highest number of rainy days are March and April (11.2 days).
Months with the lowest number of rainy days are September and October (7.8 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 shortest days is December (Average daylight: 9.5h).

  • Average sunshine in September: 8h

Months with most sunshine are June, July and August (Average sunshine: 9h).
Months with least sunshine are January, November and December (Average sunshine: 5).

Average UV index in September - Annapolis, MD
  • Average UV index in September: 7

Months with the highest UV index are June and July (UV index 9).
Months with the lowest UV index are January and December (UV index 2).