Contents
- Weather in September
- Frequently asked questions
- Average temperature in September
- Average pressure in September
- Average wind speed in September
- Average humidity in September
- Average rainfall in September
- Average rainfall days in September
- Average snowfall in September
- Average snowfall days in September
- Average sea temperature in September
- Average daylight in September
- Average sunshine in September
- Average sunshine days in September
- Average UV index in September
- Average cloud cover in September
- Average visibility in September
Weather in September
Temperature
September ushers in a minute temperature change, with average high-temperatures reducing from August's 84.7°F (29.3°C) to a still warm 79.2°F (26.2°C). Portsmouth's nighttime temperature in September drops to an average of 68.4°F (20.2°C).Humidity
In Portsmouth, the average relative humidity in September is 76%.Rainfall
In Portsmouth, in September, it is raining for 13 days, with typically 2.28" (58mm) of accumulated precipitation. Throughout the year, there are 151.9 rainfall days, and 20.35" (517mm) of precipitation is accumulated.Snowfall
In Portsmouth, snow does not fall in April through October.Ocean temperature
In Portsmouth, in September, the average water temperature is 75.6°F (24.2°C).Note: The allure of a swim in 75.6°F (24.2°C) waters can be influenced by your feelings towards the cold, today's sunshine, the wind's touch, and the ambient warmth. To put it in perspective, Olympic standards demand water temperatures of 77°F (25°C) to 82.4°F (28°C).
Daylight
The average length of the day in September is 12h and 24min.On the first day of September in Portsmouth, sunrise is at 6:36 am and sunset at 7:33 pm. On the last day of the month, sunrise is at 7:00 am and sunset at 6:49 pm EDT.
Sunshine
In September, the average sunshine is 9.4h.UV index
In Portsmouth, the average daily maximum UV index in September is 5. A UV Index estimate of 3 to 5 represents a moderate threat to health from unsafe exposure to UV radiation for ordinary individuals.Note: The maximum UV index, 5 during September, leads to the following recommendations:
Undertake protective steps - Obligation to safeguard skin and eyes from harm is in place. The Sun's harshest UV rays are around midday; it's wise to seek shade and limit time outdoors. Select sunglasses that boast both UVA and UVB protection to limit the adverse effects of the sun on the eyes. Heads up! The reflection of sand and water notably intensifies UV rays from the Sun.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What are September temperatures?
What is the average humidity in September?
How many days does it rain in September?
When it does not snow?
What is the ocean temperature in September?
How many hours of daylight does Portsmouth have in September?
When are sunrise and sunset in September?
How many hours of sunshine does Portsmouth have in September?
What is the UV index intensity in September?
Average temperature in September
Portsmouth, VA
- Average high temperature in September: 79.2°F
The warmest month (with the highest average high temperature) is July (86.4°F).
The month with the lowest average high temperature is January (45.9°F).
- Average low temperature in September: 68.4°F
The month with the highest average low temperature is July (73.6°F).
The coldest month (with the lowest average low temperature) is January (34.7°F).
Average pressure in September
Portsmouth, VA
- Average pressure in September: 30.03"Hg
The month with the highest atmospheric pressure is November (30.13"Hg).
The month with the lowest atmospheric pressure is June (29.96"Hg).
Average wind speed in September
Portsmouth, VA
- Average wind speed in September: 8.7mph
The windiest months (with the highest average wind speed) are March and April (10.5mph).
The calmest month (with the lowest average wind speed) is August (7.5mph).
Average humidity in September
Portsmouth, VA
- Average humidity in September: 76%
The month with the highest relative humidity is May (78%).
The months with the lowest relative humidity are July and November (74%).
Average rainfall in September
Portsmouth, VA
- Average rainfall in September: 2.28"
The wettest month (with the highest rainfall) is August (2.52").
The driest month (with the least rainfall) is November (1.1").
Average rainfall days in September
Portsmouth, VA
- Average rainfall days in September: 13 days
The month with the highest number of rainy days is July (17.4 days).
The month with the least rainy days is November (8.3 days).
Average snowfall in September
Portsmouth, VA
- Average snowfall in September: 0"
The month with the highest snowfall is January (0.47").
The months with the least snowfall are April, May, June, July, August, September and October (0").
Average snowfall days in September
Portsmouth, VA
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (2.2 days).
The months with the least snowfall days are April, May, June, July, August, September and October (0 days).
Average sea temperature in September
Portsmouth, VA
- Average sea temperature in September: 75.6°F
The best month for swimming (with the highest average sea temperature) is August (80°F).
The coldest month (with the lowest average sea temperature) is February (44.5°F).
Average daylight in September /
Average sunshine in September
Portsmouth, VA
- Average daylight in September: 12h and 2min
The month with the longest days is June (Average daylight: 14h and 36min).
The month with the shortest days is December (Average daylight: 9h and 42min).
- Average sunshine in September: 9h and 2min
The month with the most sunshine is July (Average sunshine: 10h and 54min).
The month with the least sunshine is February (Average sunshine: 5h and 24min).
Average sunshine days in September
Portsmouth, VA
- Average sunshine days in September: 13.9 days
The month with the most sunshine days is October (19.5 days).
The month with the least sunshine days is August (10.8 days).
Average UV index in September
Portsmouth, VA
- Average UV index in September: 5
The months with the highest UV index are July and August (UV index 7).
The month with the lowest UV index is January (UV index 2).
Average cloud cover in September
Portsmouth, VA
- Average cloud cover in September: 33
The month with the most cloud cover is March (Cloud cover 44).
The month with the least cloud cover is July (Cloud cover 26).
Average visibility in September
Portsmouth, VA
- 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).
Portsmouth, Virginia, USA
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