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's onset brings a negligible change in high-temperatures, falling from 84.7°F (29.3°C) in August to a still warm 79.2°F (26.2°C). During September, Portsmouth witnesses a consistent average low-temperature of 68.4°F (20.2°C).Humidity
The average relative humidity in September in Portsmouth is 76%.Rainfall
In Portsmouth, in September, it is raining for 13 days, with typically 2.28" (58mm) of accumulated precipitation. In Portsmouth, during the entire year, the rain falls for 151.9 days and collects up to 20.35" (517mm) of precipitation.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: Cold sensitivities vary, but with the right amount of sunshine, a gentle breeze, and a warm day, a swim in 75.6°F (24.2°C) waters might be just right. Remember, Olympic swimmers are used to waters between 77°F (25°C) and 82.4°F (28°C).
Daylight
In Portsmouth, the average length of the day in September is 12h and 24min.On the first day of September, 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 Portsmouth, the average sunshine in September is 9.4h.UV index
The average daily maximum UV index in September in Portsmouth is 5. A UV Index value of 3 to 5 symbolizes a medium vulnerability from unsafe exposure to UV radiation for the average person.Note: The UV index of 5 during September leads to these advisories:
Be mindful. Individuals with a lighter skin tone may suffer burns in less than 30 minutes. Avoid the Sun's strongest UV rays by seeking shade and limiting exposure during midday. Clothes that are both tight-knit and comfortably loose are prime choices for sun protection. Beware! Reflections from sand and water can intensify the Sun's UV radiation.
Frequently asked questions
What is the temperature in September in Portsmouth?
What is the average humidity in September in Portsmouth?
How many days does it rain in September in Portsmouth?
When it does not snow in Portsmouth?
What is the water temperature in September in Portsmouth?
How many hours of daylight does Portsmouth have in September?
When is the sunrise / sunset in September in Portsmouth?
How long on average sun shines in September in Portsmouth?
What is the UV index intensity in September in Portsmouth?
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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