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 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
As September arrives, Portsmouth's weather displays a minor decrease in high-temperatures, transitioning from August's 84.9°F (29.4°C) to a still moderately hot 78.4°F (25.8°C). A considerable shift from the daytime highs is observed during September nights, with an average low of 56.7°F (13.7°C).Humidity
The average relative humidity in September in Portsmouth is 76%.Rainfall
September is the month with the least rainfall. Rain falls for 13.3 days and accumulates 1.85" (47mm) of precipitation.Snowfall
May through September are months without snowfall in Portsmouth.Daylight
In September, the average length of the day is 12h and 26min.On the first day of the month, sunrise is at 7:01 am and sunset at 8:01 pm. On the last day of September, in Portsmouth, Ohio, sunrise is at 7:27 am and sunset at 7:15 pm EDT.
Sunshine
The average sunshine in September is 8.2h.UV index
In September, the average daily maximum UV index in Portsmouth is 4. A UV Index value of 3 to 5 symbolizes a moderate health risk from exposure to the Sun's UV radiation for the ordinary person.Note: The maximum UV index of 4 during September leads to these instructions:
Be vigilant - Suggestions to stave off sun damage are provided. The Sun's UV radiation is especially harmful around midday, so reduce exposure and stay safe. Using UVA and UVB-protective sunglasses and sun-protective clothing is effective against UV radiation.
Frequently asked questions
What is the usual temperature for Portsmouth in September?
What is the average humidity in September in Portsmouth?
What is the driest month in Portsmouth?
How much does it rain in Portsmouth in September?
When it does not snow in Portsmouth?
Does it snow in Portsmouth in September?
What is the average length of the day in September in Portsmouth?
When is the sunrise / sunset in September in Portsmouth?
How long on average sun shines in September in Portsmouth?
What is the UV index reading in September in Portsmouth?
Average temperature in September
Portsmouth, OH
- Average high temperature in September: 78.4°F
The warmest month (with the highest average high temperature) is July (86°F).
The month with the lowest average high temperature is January (37.8°F).
- Average low temperature in September: 56.7°F
The month with the highest average low temperature is July (64°F).
The coldest month (with the lowest average low temperature) is January (24.3°F).
Average pressure in September
Portsmouth, OH
- Average pressure in September: 30.04"Hg
The months with the highest atmospheric pressure are January and November (30.15"Hg).
The month with the lowest atmospheric pressure is June (29.96"Hg).
Average wind speed in September
Portsmouth, OH
- Average wind speed in September: 4.9mph
The windiest months (with the highest average wind speed) are January and February (7.5mph).
The calmest month (with the lowest average wind speed) is August (4.5mph).
Average humidity in September
Portsmouth, OH
- Average humidity in September: 76%
The months with the highest relative humidity are February and December (81%).
The month with the lowest relative humidity is August (75%).
Average rainfall in September
Portsmouth, OH
- Average rainfall in September: 1.85"
The wettest month (with the highest rainfall) is May (3.19").
The driest month (with the least rainfall) is September (1.85").
Average rainfall days in September
Portsmouth, OH
- Average rainfall days in September: 13.3 days
The month with the highest number of rainy days is May (18.3 days).
The month with the least rainy days is November (10.5 days).
Average snowfall in September
Portsmouth, OH
- Average snowfall in September: 0"
The month with the highest snowfall is January (3.19").
The months with the least snowfall are May, June, July, August and September (0").
Average snowfall days in September
Portsmouth, OH
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (10.6 days).
The months with the least snowfall days are May, June, July, August and September (0 days).
Average daylight in September /
Average sunshine in September
Portsmouth, OH
- Average daylight in September: 12h and 2min
The month with the longest days is June (Average daylight: 14h and 48min).
The month with the shortest days is December (Average daylight: 9h and 30min).
- Average sunshine in September: 8h and 1min
The month with the most sunshine is August (Average sunshine: 10h and 24min).
The month with the least sunshine is January (Average sunshine: 3h and 54min).
Average sunshine days in September
Portsmouth, OH
- Average sunshine days in September: 15.1 days
The month with the most sunshine days is November (17.3 days).
The month with the least sunshine days is February (10 days).
Average UV index in September
Portsmouth, OH
- Average UV index in September: 4
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, November and December (UV index 2).
Average cloud cover in September
Portsmouth, OH
- Average cloud cover in September: 34
The month with the most cloud cover is January (Cloud cover 60).
The month with the least cloud cover is August (Cloud cover 30).
Average visibility in September
Portsmouth, OH
- Average visibility in September: 5mi
The months with the highest visibility are March, April, June, October and November (6mi).
The months with the lowest visibility are January, February, May, July, August, September and December (5mi).
Portsmouth, Ohio, USA
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