September weather forecastBethlehem, PA
September
Weather in September
September arrives in Bethlehem softly ushering in the gentle fall season. Bethlehem enjoys a slight dip in temperature in September, resting comfortably at 74.3°F (23.5°C). Although rainfall inches reduce to 1.57" (40mm), the number of rainy days increases, hinting at shorter bursts of precipitation. The much-relaxed pace weaves a different narrative about Bethlehem's weather, with falling leaves gracing the city's streets and parks. As daytime slightly shrinks, residents transition their activities fittingly to envelope the undulating rhythms of the fall season.Temperature
Bethlehem's weather subtly changes with the onset of September, barely falling from a warm 81°F (27.2°C) in August to a still moderately hot 74.3°F (23.5°C). During the nights in September, Bethlehem observes an average low-temperature of 55°F (12.8°C).Humidity
The average relative humidity in September is 79%.Rainfall
September is the month with the least rainfall. Rain falls for 11.8 days and accumulates 1.57" (40mm) of precipitation.Snowfall
June through September are months without snowfall.Daylight
In September, the average length of the day is 12h and 27min.On the first day of the month, sunrise is at 6:29 am and sunset at 7:33 pm. On the last day of September, sunrise is at 6:57 am and sunset at 6:44 pm EDT.
Sunshine
In Bethlehem, Pennsylvania, the average sunshine in September is 8.8h.UV index
In September, the average daily maximum UV index in Bethlehem is 4. A UV Index reading of 3 to 5 represents a medium vulnerability from exposure to the Sun's UV radiation for average individuals.Note: A maximum high daily UV index of 4 during September translates into the following directions:
Preventative actions are necessary - The mandate to avoid skin and eye damage is in place. For health reasons, it's advisable to reduce direct sun exposure during peak hours around midday. 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
Average temperature in September
Bethlehem, PA
- Average high temperature in September: 74.3°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 (34°F).
- Average low temperature in September: 55°F
The month with the highest average low temperature is July (63.5°F).
The coldest month (with the lowest average low temperature) is January (21.6°F).
Average pressure in September
Bethlehem, PA
- Average pressure in September: 30.06"Hg
The month with the highest atmospheric pressure is November (30.12"Hg).
The month with the lowest atmospheric pressure is June (29.94"Hg).
Average wind speed in September
Bethlehem, PA
- Average wind speed in September: 5.5mph
The windiest month (with the highest average wind speed) is March (8.1mph).
The calmest month (with the lowest average wind speed) is August (5mph).
Average humidity in September
Bethlehem, PA
- Average humidity in September: 79%
The month with the highest relative humidity is February (82%).
The months with the lowest relative humidity are April and July (76%).
Average rainfall in September
Bethlehem, PA
- Average rainfall in September: 1.57"
The wettest month (with the highest rainfall) is July (2.91").
The driest month (with the least rainfall) is September (1.57").
Average rainfall days in September
Bethlehem, PA
- Average rainfall days in September: 11.8 days
The month with the highest number of rainy days is May (17.8 days).
The month with the least rainy days is January (7.8 days).
Average snowfall in September
Bethlehem, PA
- Average snowfall in September: 0"
The month with the highest snowfall is March (4.13").
The months with the least snowfall are June, July, August and September (0").
Average snowfall days in September
Bethlehem, PA
- Average snowfall days in September: 0 days
The months with the highest number of snowfall days are January and February (7.8 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average daylight in September /
Average sunshine in September
Bethlehem, PA
- Average daylight in September: 12h and 30min
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 18min).
- Average sunshine in September: 8h and 48min
The month with the most sunshine is July (Average sunshine: 10h and 24min).
The month with the least sunshine is February (Average sunshine: 4h and 30min).
Average sunshine days in September
Bethlehem, PA
- Average sunshine days in September: 15.6 days
The month with the most sunshine days is November (18.9 days).
The month with the least sunshine days is May (11 days).
Average UV index in September
Bethlehem, 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
Bethlehem, PA
- Average cloud cover in September: 39
The month with the most cloud cover is February (Cloud cover 51).
The month with the least cloud cover is July (Cloud cover 34).
Average visibility in September
Bethlehem, PA
- Average visibility in September: 5mi
The months with the highest visibility are April, June and November (6mi).
The months with the lowest visibility are January, February, March, May, July, August, September, October and December (5mi).
