September weather forecast
Bethlehem, PA

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A tranquil setting of dry trees and neat fields behind this large hall in the Lehigh University in Bethlehem, Pennsylvania
A tranquil setting of dry trees and neat fields behind this large hall in the Lehigh University in Bethlehem, Pennsylvania

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.

Frequently asked questions

What is the temperature in September?

The high-temperature during September is 74.3°F (23.5°C) and the low-temperature is 55°F (12.8°C). In August, the average heat index (a.k.a. 'real feel', 'apparent temperature'), which calculates the temperature value influenced by the moisture in the air, is appraised at 86°F (30°C).

What is the average humidity in September?

In September, the average relative humidity is 79%.

What is the driest month?

The month with the least rainfall is September, when the rain falls for 11.8 days and typically collects 1.57" (40mm) of precipitation.

How much does it rain in September?

In Bethlehem, during September, the rain falls for 11.8 days and regularly aggregates up to 1.57" (40mm) of precipitation.

When it does not snow?

In Bethlehem, snow does not fall in June through September.

Does it snow in September?

In Bethlehem, in September, it doesn't snow. In October, it regularly snows.

What is the average length of the day in September?

The average day length in September is 12h and 27min.

What time are sunrise and sunset in September?

In September, on the first day of the month, sunrise is at 6:29 am and sunset at 7:33 pm. On the last day of the month, sunrise is at 6:57 am and sunset at 6:44 pm EDT.

How long on average sun shines in September in Bethlehem?

In September, the average sunshine duration is 8.8h.

What is the UV index intensity in September?

In Bethlehem, the average daily maximum UV index in September is 4. A UV Index reading of 3 to 5 represents a moderate vulnerability from unprotected exposure to UV radiation.
Average humidity
Average rainfall days
Average snowfall
Average snowfall days
Average daylight
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in September
Bethlehem, PA

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 - 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 - 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 - 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 - 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 - 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 - 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 - 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 / Average sunshine in September - Bethlehem, PA
  • Average daylight in September: 12h and 3min

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 5min

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 - 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 - 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 - 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 - 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).

Bethlehem, Pennsylvania, USA

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