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
Transition into September subtly marks a drop in the average high-temperature, moderately moving from a warm 80.4°F (26.9°C) in August to a pleasant 72.7°F (22.6°C). An average low-temperature of 57.4°F (14.1°C) is recorded during the nights in September.Humidity
In Boston, the average relative humidity in September is 75%.Rainfall
The month with the least rainfall is September, when the rain falls for 10 days and typically collects 1.26" (32mm) of precipitation.Snowfall
In Boston, Massachusetts, snow does not fall in June through September.Ocean temperature
In Boston, the average seawater temperature in September is 64.8°F (18.2°C).Note: The enjoyment of swimming decreases for most when the surface water temperature is 64.8°F (18.2°C). Breathing control becomes increasingly challenging as temperatures descend below 69.8°F (21°C).
Daylight
The average length of the day in September in Boston is 12h and 28min.On the first day of September, sunrise is at 6:10 am and sunset at 7:17 pm. On the last day of the month, sunrise is at 6:40 am and sunset at 6:26 pm EDT.
Sunshine
The average sunshine in September is 8.4h.UV index
In Boston, the average daily maximum UV index in September is 4. A UV Index value of 3 to 5 symbolizes a medium vulnerability from unprotected exposure to Sun's UV rays for the average person.Note: In September, the maximum UV index of 4 suggests this advice:
Heed the precautions - Suggestions to avoid sunburn are made. The intensity of the Sun's UV radiation during midday suggests reducing time spent outdoors. On days when the sun blazes, arm yourself with sunglasses that block UVA and UVB radiation.
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Data Sources | Weather Forecasting & Climate
Frequently asked questions
What are the temperatures in September?
What is the average humidity in September?
What is the driest month?
How many days 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?
What is the UV index intensity in September?
Average temperature in September
Boston, 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
Boston, 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
Boston, 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
Boston, 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
Boston, 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
Boston, 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
Boston, 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
Boston, 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
Boston, 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
Boston, 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
Boston, 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
Boston, 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
Boston, 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
Boston, 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).
Boston, Massachusetts, USA
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