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
In Chelsea, the average high-temperature in September gently drops from a moderately hot 80.4°F (26.9°C) in August to an agreeable 72.7°F (22.6°C). Throughout September, the nighttime temperature averages to a refreshing 57.4°F (14.1°C).Humidity
In Chelsea, the average relative humidity in September is 75%.Rainfall
September is the month with the least rainfall. Rain falls for 10 days and accumulates 1.26" (32mm) of precipitation.Snowfall
June through September are months without snowfall.Ocean temperature
In Chelsea, Massachusetts, in September, the average water temperature is 64.8°F (18.2°C).Note: The majority of people do not enjoy swimming in 64.8°F (18.2°C). The difficulty in controlling breathing escalates as the temperature descends from 69.8°F (21°C) to 59°F (15°C).
Daylight
In September, the average length of the day is 12h and 28min.On the first day of the month, sunrise is at 6:10 am and sunset at 7:17 pm. On the last day of September, sunrise is at 6:40 am and sunset at 6:26 pm EDT.
Sunshine
In September, the average sunshine is 8.4h.UV index
In Chelsea, the average daily maximum UV index in September is 4. A UV Index estimate of 3 to 5 represents a moderate health risk from exposure to the Sun's UV radiation for ordinary individuals.Note: The maximum daily UV index, 4 in September, converts into the following recommendations:
Put precautions into practice - Protective measures against sun-induced damage are advised. For health reasons, it's advisable to reduce direct sun exposure during peak hours around midday. A hat with a broad brim is indispensable, filtering out up to half of UV rays.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What are the temperatures in Chelsea in September?
What is the average humidity in September?
What is the driest month?
How much does it rain in September?
When it does not snow?
Does it snow in September?
What is the ocean temperature in September?
What is the average length of the day in September?
When is the sunrise / sunset in September?
How long on average sun shines in September?
How high is the UV index in September?
Average temperature in September
Chelsea, MA
- Average high temperature in September: 72.7°F
The warmest month (with the highest average high temperature) is July (81.7°F).
The month with the lowest average high temperature is January (34.2°F).
- Average low temperature in September: 57.4°F
The month with the highest average low temperature is July (64.9°F).
The coldest month (with the lowest average low temperature) is January (22.6°F).
Average pressure in September
Chelsea, 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
Chelsea, MA
- Average wind speed in September: 6.8mph
The windiest month (with the highest average wind speed) is January (9.9mph).
The calmest month (with the lowest average wind speed) is August (6.2mph).
Average humidity in September
Chelsea, MA
- Average humidity in September: 75%
The month with the highest relative humidity is February (77%).
The month with the lowest relative humidity is April (69%).
Average rainfall in September
Chelsea, MA
- Average rainfall in September: 1.26"
The wettest months (with the highest rainfall) are March, April and December (2.91").
The driest month (with the least rainfall) is September (1.26").
Average rainfall days in September
Chelsea, MA
- Average rainfall days in September: 10 days
The month with the highest number of rainy days is May (15.3 days).
The month with the least rainy days is January (7.9 days).
Average snowfall in September
Chelsea, MA
- Average snowfall in September: 0"
The month with the highest snowfall is February (4.72").
The months with the least snowfall are June, July, August and September (0").
Average snowfall days in September
Chelsea, MA
- Average snowfall days in September: 0 days
The months with the highest number of snowfall days are January and February (7.6 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average sea temperature in September
Chelsea, MA
- Average sea temperature in September: 64.8°F
The best month for swimming (with the highest average sea temperature) is August (67.9°F).
The coldest month (with the lowest average sea temperature) is February (38.1°F).
Average daylight in September /
Average sunshine in September
Chelsea, 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 2min
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
Chelsea, MA
- Average sunshine days in September: 17.7 days
The month with the most sunshine days is September (17.7 days).
The month with the least sunshine days is April (13 days).
Average UV index in September
Chelsea, 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
Chelsea, MA
- Average cloud cover in September: 37
The month with the most cloud cover is March (Cloud cover 51).
The month with the least cloud cover is August (Cloud cover 32).
Average visibility in September
Chelsea, 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).
Chelsea, Massachusetts, USA
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