September weather forecast
Saint Peters, PA

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Weather in September

The first month of the autumn, September, is still a warm month in Saint Peters, Pennsylvania, with an average temperature varying between 75°F (23.9°C) and 56.5°F (13.6°C).

Temperature

The advent of September brings a subtle shift in temperature, with the average high moving from 81.1°F (27.3°C) in August to a still moderately hot 75°F (23.9°C). Saint Peters's average low-temperature is measured at a mild 56.5°F (13.6°C) during September.

Humidity

In September, the average relative humidity in Saint Peters is 79%.

Rainfall

September is the month with the least rainfall. Rain falls for 12.9 days and accumulates 1.77" (45mm) of precipitation.

Snowfall

June through September are months without snowfall.

Daylight

In Saint Peters, the average length of the day in September is 12h and 26min.
On the first day of September, sunrise is at 6:31 am and sunset at 7:34 pm. On the last day of the month, sunrise is at 6:58 am and sunset at 6:46 pm EDT.

Sunshine

In Saint Peters, the average sunshine in September is 8.9h.

UV index

In Saint Peters, the average daily maximum UV index in September is 4. A UV Index reading of 3 to 5 represents a moderate health risk from unsafe exposure to UV radiation for the ordinary person.
Note: A daily high UV index of 4 in September leads to these guidelines:
Act with care - Obligation to protect against skin and eye damage is highlighted. Being exposed to the midday Sun can have harmful effects due to strong UV radiation; always take precautions. Sun protection is enhanced with clothing that boasts a tight weave yet offers a loose fit.

Frequently asked questions

What is the average September temperature?

Saint Peters in September has an average high-temperature of 75°F (23.9°C) and an average low-temperature of 56.5°F (13.6°C). The average heat index (a.k.a. 'real feel', 'feels like'), which represents the influence of relative humidity on air temperature, in August is estimated at 86°F (30°C).

What is the average humidity in September in Saint Peters?

In Saint Peters, the average relative humidity in September is 79%.

What is the driest month in Saint Peters?

The month with the least rainfall is September, when the rain falls for 12.9 days and typically collects 1.77" (45mm) of precipitation.

How many days does it rain in September?

In Saint Peters, during September, the rain falls for 12.9 days and regularly aggregates up to 1.77" (45mm) of precipitation.

When it does not snow?

In Saint Peters, snow does not fall in June through September.

Does it snow in September?

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

How many hours of daylight does Saint Peters have in September?

The average day length in September is 12h and 26min.

When are sunrise and sunset in September?

On the first day of September, sunrise is at 6:31 am and sunset at 7:34 pm. On the last day of the month, sunrise is at 6:58 am and sunset at 6:46 pm EDT.

How many hours of sunshine does Saint Peters have in September?

In September, the average sunshine duration is 8.9h.

What is the UV index intensity in September?

The average daily maximum UV index in September is 4. A UV Index reading of 3 to 5 represents a medium health risk from unsafe exposure to Sun's UV rays.
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
Saint Peters, PA

Average temperature in September - Saint Peters, PA
  • Average high temperature in September: 75°F

The warmest month (with the highest average high temperature) is July (83.7°F).
The month with the lowest average high temperature is January (35.2°F).

  • Average low temperature in September: 56.5°F

The month with the highest average low temperature is July (64.2°F).
The coldest month (with the lowest average low temperature) is January (22.8°F).

Average pressure in September
Saint Peters, PA

Average pressure in September - Saint Peters, PA
  • Average pressure in September: 30.06"Hg

The month with the highest atmospheric pressure is November (30.13"Hg).
The month with the lowest atmospheric pressure is June (29.94"Hg).

Average wind speed in September
Saint Peters, PA

Average wind speed in September - Saint Peters, PA
  • Average wind speed in September: 5.4mph

The windiest months (with the highest average wind speed) are January and March (8.3mph).
The calmest month (with the lowest average wind speed) is August (4.8mph).

Average humidity in September
Saint Peters, PA

Average humidity in September - Saint Peters, PA
  • Average humidity in September: 79%

The months with the highest relative humidity are February and October (81%).
The month with the lowest relative humidity is April (76%).

Average rainfall in September
Saint Peters, PA

Average rainfall in September - Saint Peters, PA
  • Average rainfall in September: 1.77"

The wettest month (with the highest rainfall) is August (2.83").
The driest month (with the least rainfall) is September (1.77").

Average rainfall days in September
Saint Peters, PA

Average rainfall days in September - Saint Peters, PA
  • Average rainfall days in September: 12.9 days

The month with the highest number of rainy days is May (17.4 days).
The month with the least rainy days is January (9.4 days).

Average snowfall in September
Saint Peters, PA

Average snowfall in September - Saint Peters, PA
  • Average snowfall in September: 0"

The month with the highest snowfall is March (3.03").
The months with the least snowfall are June, July, August and September (0").

Average snowfall days in September
Saint Peters, PA

Average snowfall days in September - Saint Peters, PA
  • Average snowfall days in September: 0 days

The month with the highest number of snowfall days is January (7.3 days).
The months with the least snowfall days are June, July, August and September (0 days).

Average daylight in September /
Average sunshine in September
Saint Peters, PA

Average daylight in September / Average sunshine in September - Saint Peters, PA
  • Average daylight in September: 12h and 2min

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 5min

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 42min).

Average sunshine days in September
Saint Peters, PA

Average sunshine days in September - Saint Peters, PA
  • Average sunshine days in September: 15.2 days

The month with the most sunshine days is November (17.8 days).
The month with the least sunshine days is May (11.6 days).

Average UV index in September
Saint Peters, PA

Average UV index in September - Saint Peters, 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
Saint Peters, PA

Average cloud cover in September - Saint Peters, PA
  • Average cloud cover in September: 38

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 31).

Average visibility in September
Saint Peters, PA

Average visibility in September - Saint Peters, PA
  • Average visibility in September: 5mi

The months with the highest visibility are January, March, April, June, July, August, November and December (6mi).
The months with the lowest visibility are February, May, September and October (5mi).

Saint Peters, Pennsylvania, USA

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