September weather forecastGrantham, PA
September
Weather in September
The first month of the autumn, September, is also a moderately hot month in Grantham, Pennsylvania, with an average temperature varying between 56.1°F (13.4°C) and 74.7°F (23.7°C).Temperature
Grantham experiences a moderate temperature shift at the start of September, with average high-temperatures adjusting a bit from a warm 81.1°F (27.3°C) in August to a still moderately hot 74.7°F (23.7°C). Grantham temperatures generally rest at a low of 56.1°F (13.4°C) during the September nights.Humidity
In September, the average relative humidity in Grantham is 79%.Rainfall
In Grantham, in September, during 11.1 rainfall days, 1.34" (34mm) of precipitation is typically accumulated. Throughout the year, there are 137.7 rainfall days, and 18.43" (468mm) of precipitation is accumulated.Snowfall
In Grantham, Pennsylvania, snow does not fall in May through September.Daylight
In Grantham, the average length of the day in September is 12h and 26min.On the first day of the month, sunrise is at 6:36 am and sunset at 7:39 pm. On the last day of September, sunrise is at 7:04 am and sunset at 6:51 pm EDT.
Sunshine
In September, the average sunshine is 8.9h.UV index
In Grantham, the average daily maximum UV index in September is 4. A UV Index estimate of 3 to 5 represents a moderate health risk from unsafe exposure to UV radiation for ordinary individuals.Note: The maximum UV index, 4 during September, leads to the following recommendations:
Undertake precautions - Guarding against sun damage is counselled. Exposing oneself to the midday Sun can be harmful due to the strong UV radiation; limit your time outside. Enhance your sun protection with tightly woven, yet airy clothing.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Grantham, PA
- Average high temperature in September: 74.7°F
The warmest month (with the highest average high temperature) is July (83.5°F).
The month with the lowest average high temperature is January (35.2°F).
- Average low temperature in September: 56.1°F
The month with the highest average low temperature is July (64.6°F).
The coldest month (with the lowest average low temperature) is January (22.5°F).
Average pressure in September
Grantham, PA
- Average pressure in September: 30.06"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
Grantham, PA
- Average wind speed in September: 5.5mph
The windiest months (with the highest average wind speed) are February, March and April (8.4mph).
The calmest months (with the lowest average wind speed) are July and August (5mph).
Average humidity in September
Grantham, PA
- Average humidity in September: 79%
The months with the highest relative humidity are February and May (80%).
The month with the lowest relative humidity is April (75%).
Average rainfall in September
Grantham, PA
- Average rainfall in September: 1.34"
The wettest months (with the highest rainfall) are May and July (2.05").
The driest month (with the least rainfall) is January (1.14").
Average rainfall days in September
Grantham, PA
- Average rainfall days in September: 11.1 days
The month with the highest number of rainy days is May (15.6 days).
The month with the least rainy days is January (6.3 days).
Average snowfall in September
Grantham, PA
- Average snowfall in September: 0"
The month with the highest snowfall is January (2.52").
The months with the least snowfall are May, June, July, August and September (0").
Average snowfall days in September
Grantham, PA
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (7.2 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average daylight in September /
Average sunshine in September
Grantham, PA
- Average daylight in September: 12h and 24min
The month with the longest days is June (Average daylight: 15h and 0min).
The month with the shortest days is December (Average daylight: 9h and 24min).
- Average sunshine in September: 8h and 54min
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 36min).
Average sunshine days in September
Grantham, PA
- Average sunshine days in September: 16.6 days
The month with the most sunshine days is November (20 days).
The month with the least sunshine days is May (12.2 days).
Average UV index in September
Grantham, PA
- Average UV index in September: 4
The months with the highest UV index are May, June and July (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
Grantham, PA
- Average cloud cover in September: 37
The months with the most cloud cover are February and December (Cloud cover 49).
The month with the least cloud cover is July (Cloud cover 30).
Average visibility in September
Grantham, PA
- Average visibility in September: 5mi
The months with the highest visibility are January, February, March, April, June, July, August, October, November and December (6mi).
The months with the lowest visibility are May and September (5mi).
