September weather forecast
Fresno, CA

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The artificial Millerton Lake near Fresno in California
The artificial Millerton Lake near Fresno in California

Weather in September

September signals an imminent change, with the sharp summer heat undergoing a reduction to pave the way for the cooler autumnal weather. This month, the worst of the summer heat subsides, giving way to a slightly cooler temperature of 91.8°F (33.2°C). The lowering temperatures are accompanied by a marginal rise in humidity levels, giving a faint hint of moisture to the otherwise dry Californian air. The wind speed maintains its consistency, and the daylight hours progressively decrease. Consequently, September's weather is a herald for the onset of autumn, making it a period of noticeable climatic transition.

Temperature

September is characterized by a mild reduction in the average high-temperature, from a torrid 98.2°F (36.8°C) in August to a hot 91.8°F (33.2°C). During September, Fresno notes a substantial drop from the daytime peak to an average minimum temperature of 63.3°F (17.4°C).

Humidity

The average relative humidity in September is 31%.

Rainfall

In Fresno, in September, it is raining for 2.4 days, with typically 0.16" (4mm) of accumulated precipitation. In Fresno, California, during the entire year, the rain falls for 59.3 days and collects up to 10.43" (265mm) of precipitation.

Daylight

In September, the average length of the day in Fresno is 12h and 24min.
On the first day of the month, sunrise is at 6:30 am and sunset at 7:26 pm. On the last day of September, sunrise is at 6:54 am and sunset at 6:43 pm PDT.

Sunshine

In September, the average sunshine is 11.2h.

UV index

The average daily maximum UV index in September is 6. A UV Index estimate of 6 to 7 represents a high health vulnerability from unprotected exposure to Sun's UV rays for ordinary individuals.
Note: The average daily UV index of 6 in September transforms into the following instructions:
Shun overexposure. Protection from sun ravages is indispensable. Avoid direct exposure to the Sun between 10 a.m. and 4 p.m., the peak period for UV radiation, noting that objects like parasols or canopies might not offer complete sun protection. Prioritize a wide-brim hat for comprehensive sun defense for your face, neck, eyes, and ears.
Updated: Aug 18, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

How hot is it in September?

The average high-temperature, in September, in Fresno, is 91.8°F (33.2°C), while the average low-temperature is 63.3°F (17.4°C). In May, the average heat index (a.k.a. 'felt air temperature', 'feels like'), which combines relative humidity and air temperature, is computed to be 80.6°F (27°C).

What is the average humidity in September?

In September, the average relative humidity is 31%.

How many days does it rain in September?

In Fresno, in September, during 2.4 rainfall days, 0.16" (4mm) of precipitation is typically accumulated.

How many hours of daylight does Fresno have in September?

The average day length in September is 12h and 24min.

What time are sunrise and sunset in September?

In September, on the first day of the month, sunrise is at 6:30 am and sunset at 7:26 pm. On the last day of the month, sunrise is at 6:54 am and sunset at 6:43 pm PDT.

How long on average sun shines in September?

In September, the average sunshine duration is 11.2h.

How high is the UV index in September?

In Fresno, the average daily maximum UV index in September is 6. A UV Index estimate of 6 to 7 represents a high health vulnerability from unsafe exposure to Sun's UV rays.
Average humidity
Average rainfall days
Average daylight
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in September
Fresno, CA

Average temperature in September - Fresno, CA
  • Average high temperature in September: 91.8°F

The warmest month (with the highest average high temperature) is July (99.7°F).
The month with the lowest average high temperature is December (56.1°F).

  • Average low temperature in September: 63.3°F

The month with the highest average low temperature is July (67.3°F).
The coldest month (with the lowest average low temperature) is December (41.4°F).

Average pressure in September
Fresno, CA

Average pressure in September - Fresno, CA
  • Average pressure in September: 29.92"Hg

The month with the highest atmospheric pressure is January (30.15"Hg).
The month with the lowest atmospheric pressure is June (29.89"Hg).

Average wind speed in September
Fresno, CA

Average wind speed in September - Fresno, CA
  • Average wind speed in September: 4.6mph

The windiest month (with the highest average wind speed) is June (5.8mph).
The calmest month (with the lowest average wind speed) is November (3.8mph).

Average humidity in September
Fresno, CA

Average humidity in September - Fresno, CA
  • Average humidity in September: 31%

The month with the highest relative humidity is January (65%).
The month with the lowest relative humidity is July (28%).

Average rainfall in September
Fresno, CA

Average rainfall in September - Fresno, CA
  • Average rainfall in September: 0.16"

The wettest month (with the highest rainfall) is March (2.01").
The driest months (with the least rainfall) are June and August (0.08").

Average rainfall days in September
Fresno, CA

Average rainfall days in September - Fresno, CA
  • Average rainfall days in September: 2.4 days

The month with the highest number of rainy days is March (10.3 days).
The month with the least rainy days is August (1.2 days).

Average daylight in September /
Average sunshine in September
Fresno, CA

Average daylight in September / Average sunshine in September - Fresno, CA
  • Average daylight in September: 12h and 2min

The month with the longest days is June (Average daylight: 14h and 36min).
The month with the shortest days is December (Average daylight: 9h and 42min).

  • Average sunshine in September: 11h and 1min

The months with the most sunshine are June, July and August (Average sunshine: 12h and 6min).
The month with the least sunshine is December (Average sunshine: 6h and 30min).

Average sunshine days in September
Fresno, CA

Average sunshine days in September - Fresno, CA
  • Average sunshine days in September: 26.8 days

The month with the most sunshine days is August (28.2 days).
The month with the least sunshine days is March (19.5 days).

Average UV index in September
Fresno, CA

Average UV index in September - Fresno, CA
  • Average UV index in September: 6

The months with the highest UV index are June, July and August (UV index 7).
The months with the lowest UV index are January, November and December (UV index 3).

Average cloud cover in September
Fresno, CA

Average cloud cover in September - Fresno, CA
  • Average cloud cover in September: 6

The month with the most cloud cover is March (Cloud cover 27).
The month with the least cloud cover is August (Cloud cover 4).

Average visibility in September
Fresno, CA

Average visibility in September - Fresno, CA
  • Average visibility in September: 6mi

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

Fresno, California, USA

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