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
A subtle change in temperatures is noted as August gives way to September, with average highs reducing from a moderately hot 85.6°F (29.8°C) to a still warm 78.4°F (25.8°C). September's average low-temperature reading settles at a refreshing 61.7°F (16.5°C).Humidity
In September, the average relative humidity is 73%.Rainfall
In Adelphi, in September, it is raining for 12.4 days, with typically 2.2" (56mm) of accumulated precipitation. In Adelphi, during the entire year, the rain falls for 154.8 days and collects up to 30.28" (769mm) of precipitation.Snowfall
In Adelphi, snow does not fall in May through October.Daylight
In Adelphi, Maryland, the average length of the day in September is 12h and 26min.On the first day of September, sunrise is at 6:37 am and sunset at 7:37 pm. On the last day of the month, sunrise is at 7:03 am and sunset at 6:51 pm EDT.
Sunshine
The average sunshine in September is 8.7h.UV index
The average daily maximum UV index in September is 5. A UV Index estimate of 3 to 5 represents a moderate threat to health from unprotected exposure to Sun's UV rays for average individuals.Note: In September, the average maximum UV index of 5 translates into the following recommendations:
Adopt protective measures - Suggestions to resist sunburn are offered. The intensity of the Sun's UV radiation during midday suggests reducing time spent outdoors. Loose clothes with a tight weave are optimal for safeguarding yourself against the Sun's rays.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What are the temperatures in September?
What is the average humidity in September?
How much does it rain in September?
When it does not snow?
How many hours of daylight does Adelphi have in September?
What time are sunrise and sunset in September?
How long on average sun shines in September?
What is the UV index intensity in September?
Average temperature in September
Adelphi, MD
- Average high temperature in September: 78.4°F
The warmest month (with the highest average high temperature) is July (87.4°F).
The month with the lowest average high temperature is January (39.7°F).
- Average low temperature in September: 61.7°F
The month with the highest average low temperature is July (69.6°F).
The coldest month (with the lowest average low temperature) is January (27.1°F).
Average pressure in September
Adelphi, MD
- Average pressure in September: 30.05"Hg
The month with the highest atmospheric pressure is November (30.14"Hg).
The month with the lowest atmospheric pressure is June (29.95"Hg).
Average wind speed in September
Adelphi, MD
- Average wind speed in September: 5.8mph
The windiest month (with the highest average wind speed) is March (8.1mph).
The calmest month (with the lowest average wind speed) is August (5.2mph).
Average humidity in September
Adelphi, MD
- Average humidity in September: 73%
The months with the highest relative humidity are May, October and December (75%).
The month with the lowest relative humidity is July (69%).
Average rainfall in September
Adelphi, MD
- Average rainfall in September: 2.2"
The wettest month (with the highest rainfall) is August (3.86").
The driest month (with the least rainfall) is January (1.89").
Average rainfall days in September
Adelphi, MD
- Average rainfall days in September: 12.4 days
The month with the highest number of rainy days is May (17.7 days).
The month with the least rainy days is November (8.5 days).
Average snowfall in September
Adelphi, MD
- Average snowfall in September: 0"
The month with the highest snowfall is January (2.87").
The months with the least snowfall are May, June, July, August, September and October (0").
Average snowfall days in September
Adelphi, MD
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (4.6 days).
The months with the least snowfall days are May, June, July, August, September and October (0 days).
Average daylight in September /
Average sunshine in September
Adelphi, MD
- Average daylight in September: 12h and 2min
The month with the longest days is June (Average daylight: 14h and 54min).
The month with the shortest days is December (Average daylight: 9h and 30min).
- Average sunshine in September: 8h and 4min
The month with the most sunshine is July (Average sunshine: 10h and 36min).
The month with the least sunshine is February (Average sunshine: 4h and 54min).
Average sunshine days in September
Adelphi, MD
- Average sunshine days in September: 16.1 days
The month with the most sunshine days is November (19.5 days).
The month with the least sunshine days is May (12 days).
Average UV index in September
Adelphi, MD
- Average UV index in September: 5
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, November and December (UV index 2).
Average cloud cover in September
Adelphi, MD
- Average cloud cover in September: 38
The month with the most cloud cover is March (Cloud cover 47).
The month with the least cloud cover is July (Cloud cover 32).
Average visibility in September
Adelphi, MD
- Average visibility in September: 6mi
The months with the highest visibility are January, February, March, April, June, July, August, September, October, November and December (6mi).
The month with the lowest visibility is May (5mi).
Adelphi, Maryland, USA
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