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
September is marked by a subtle drop in average high-temperatures, transitioning from a moderately hot 80.4°F (26.9°C) in August to an agreeable 72.9°F (22.7°C). An average low-temperature of 56.8°F (13.8°C) is observed in Charlestown during the September nights.Humidity
In Charlestown, the average relative humidity in September is 75%.Rainfall
September is the month with the least rainfall. Rain falls for 2.9 days and accumulates 0.12" (3mm) of precipitation.Snowfall
June through October are months without snowfall.Daylight
In September, the average length of the day is 12h and 28min.On the first day of September in Charlestown, sunrise is at 6:10 am and sunset at 7:17 pm. On the last day of the month, sunrise is at 6:41 am and sunset at 6:26 pm EDT.
Sunshine
The average sunshine in September is 8.5h.UV index
In Charlestown, Massachusetts, the average daily maximum UV index in September is 4. A UV Index reading of 3 to 5 represents a medium vulnerability from exposure to the Sun's UV rays for the average person.Note: The maximum UV index of 4 during September leads to these instructions:
Exercise care. People with light skin might get burns in fewer than 30 minutes. To avoid the Sun's strongest rays, limit exposure around the mid-day period. Sunglasses that ward off UVA and UVB rays play a pivotal role in reducing solar eye damage.
Frequently asked questions
What are September temperatures in Charlestown?
What is the average humidity in September in Charlestown?
What is the driest month in Charlestown?
How much does it rain in Charlestown in September?
When it does not snow in Charlestown?
What is the average length of the day in September in Charlestown?
What time are sunrise and sunset in September in Charlestown?
How long on average sun shines in September in Charlestown?
How high is the UV index in September in Charlestown?
Average temperature in September
Charlestown, MA
- Average high temperature in September: 72.9°F
The warmest month (with the highest average high temperature) is July (81.9°F).
The month with the lowest average high temperature is January (33.8°F).
- Average low temperature in September: 56.8°F
The month with the highest average low temperature is July (64.8°F).
The coldest month (with the lowest average low temperature) is January (22.5°F).
Average pressure in September
Charlestown, MA
- Average pressure in September: 30.05"Hg
The month with the highest atmospheric pressure is November (30.06"Hg).
The month with the lowest atmospheric pressure is June (29.93"Hg).
Average wind speed in September
Charlestown, MA
- Average wind speed in September: 6.6mph
The windiest month (with the highest average wind speed) is January (9.6mph).
The calmest month (with the lowest average wind speed) is August (6mph).
Average humidity in September
Charlestown, MA
- Average humidity in September: 75%
The month with the highest relative humidity is February (78%).
The month with the lowest relative humidity is April (69%).
Average rainfall in September
Charlestown, MA
- Average rainfall in September: 0.12"
The wettest month (with the highest rainfall) is November (0.55").
The driest month (with the least rainfall) is September (0.12").
Average rainfall days in September
Charlestown, MA
- Average rainfall days in September: 2.9 days
The month with the highest number of rainy days is April (5.9 days).
The months with the least rainy days are January and September (2.9 days).
Average snowfall in September
Charlestown, MA
- Average snowfall in September: 0"
The month with the highest snowfall is December (0.71").
The months with the least snowfall are June, July, August, September and October (0").
Average snowfall days in September
Charlestown, MA
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (3.4 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average daylight in September /
Average sunshine in September
Charlestown, MA
- Average daylight in September: 12h and 3min
The month with the longest days is June (Average daylight: 15h and 12min).
The month with the shortest days is December (Average daylight: 9h and 6min).
- Average sunshine in September: 8h and 3min
The month with the most sunshine is August (Average sunshine: 10h and 30min).
The month with the least sunshine is February (Average sunshine: 4h and 36min).
Average sunshine days in September
Charlestown, MA
- Average sunshine days in September: 24.8 days
The month with the most sunshine days is December (25.5 days).
The month with the least sunshine days is July (22.8 days).
Average UV index in September
Charlestown, MA
- Average UV index in September: 4
The months with the highest UV index are June, July and August (UV index 6).
The months with the lowest UV index are January, February, March, November and December (UV index 2).
Average cloud cover in September
Charlestown, MA
- Average cloud cover in September: 37
The month with the most cloud cover is March (Cloud cover 50).
The month with the least cloud cover is August (Cloud cover 32).
Average visibility in September
Charlestown, MA
- 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).
Charlestown, Massachusetts, USA
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