September weather forecast
Modesto, CA

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Weather in September

September, the first month of the autumn in Modesto, is still a tropical month, with temperature in the range of an average high of 90.9°F and an average low of 59.9°F.

Temperature

September ushers in a minute temperature change, with average high-temperatures reducing from August's very hot 96.4°F to a hot 90.9°F. The nighttime temperature in Modesto, California, shows a significant divergence from the daytime highs, averaging at a mild 59.9°F in September.

Heat index

The average heat index in September is appraised at a hot 93.2°F. Adopt special protective actions against heat exhaustion and heat cramps. Long-duration activity risks heatstroke.
In the scope of the heat index, its values resonate with shade and light wind conditions. Heat index values may be hiked up by 15 Fahrenheit (8 Celsius) degrees under direct sunshine.
Note: The heat index, also known as 'real feel' or 'feels like', is a metric representing the sensation of warmth when air temperature and moisture come together. Factors encompassing physical activity, clothing, and metabolic differences have a role in shaping the individual's impression of temperature. Keep in mind that direct sunshine exposure can amplify the weather's effects, possibly increasing the heat index by up to 15 Fahrenheit (8 Celsius) degrees. Heat index values are particularly relevant to children. Children frequently do not understand the need for recuperation and hydration. Thirst, being a late manifestation of dehydration, underlines the need to hydrate frequently, especially when engaging in prolonged physical exercises.

Humidity

In Modesto, California, the average relative humidity in September is 41%.

Rainfall

In Modesto, in September, it is raining for 1.6 days, with typically 0.08" of accumulated precipitation. In Modesto, during the entire year, the rain falls for 54.3 days and collects up to 6.54" of precipitation.

Daylight

The average length of the day in September in Modesto is 12h and 25min.
On the first day of the month, sunrise is at 6:34 am and sunset at 7:33 pm. On the last day of September, sunrise is at 6:58 am and sunset at 6:49 pm PDT.

Sunshine

In September, the average sunshine in Modesto is 11.5h.

UV index

In Modesto, the average daily maximum UV index in September is 6. A UV Index reading of 6 to 7 represents a high health hazard from unprotected exposure to Sun's UV rays for the ordinary person.
Note: The daily maximum UV index of 6 in September interprets into the following advice:
Persist with precautions and heed sun safety advice. Prevention of sunburn is compulsory. Remember that UV radiation from the Sun is strongest between 10 a.m. and 4 p.m. Make an effort to limit direct sun exposure during this time. On bright days sunglasses that block both UVA and UVB rays should be worn. A hat with a wide brim is extremely helpful, as it can prevent roughly 50% of UV radiation from reaching the eyes.
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FAQ

How hot is it in Modesto in September?

In Modesto, 90.9°F is the average high-temperature and 59.9°F is the average low-temperature during September. The average heat index (a.k.a. 'felt air temperature', 'feels like'), which takes the relative humidity and factors it into the air temperature reading, in September is appraised at 93.2°F.

What is the average humidity in September in Modesto?

The average relative humidity in September in Modesto, California, is 41%.

How much does it rain in Modesto in September?

In Modesto, California, during September, the rain falls for 1.6 days and regularly aggregates up to 0.08" of precipitation.

How many hours of daylight does Modesto have in September?

The average day length in September is 12h and 25min.

When are sunrise and sunset in September in Modesto?

In September, on the first day of the month, sunrise is at 6:34 am and sunset at 7:33 pm. On the last day of the month, sunrise is at 6:58 am and sunset at 6:49 pm PDT.

How many hours of sunshine does Modesto have in September?

The average sunshine duration in September in Modesto is 11.5h.

What is the UV index reading in September in Modesto?

In Modesto, California, the average daily maximum UV index in September is 6. A UV Index of 6 to 7 symbolizes a high health vulnerability from unprotected exposure to UV radiation.
Average high temperature
Average low temperature
Average pressure
Average wind speed
Average max. wind speed
Average wind speed gusts
Average humidity
Average rainfall
Average rainfall days
Average daylight
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in September
Modesto, CA

Average temperature in September - Modesto, CA
  • Average high temperature in September: 90.9°F

The warmest month (with the highest average high temperature) is July (97.7°F).
The month with the lowest average high temperature is December (55.6°F).

  • Average low temperature in September: 59.9°F

The month with the highest average low temperature is July (62.1°F).
The coldest months (with the lowest average low temperature) are January and December (41.9°F).

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Average pressure in September
Modesto, CA

Average pressure in September - Modesto, CA
  • Average pressure in September: 29.93"Hg

The month with the highest atmospheric pressure is January (30.15"Hg).
The month with the lowest atmospheric pressure is June (29.91"Hg).

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Average wind speed in September
Modesto, CA

Average wind speed in September - Modesto, CA
  • Average wind speed in September: 5.8mph

The windiest month (with the highest average wind speed) is June (7.3mph).
The calmest month (with the lowest average wind speed) is November (5.2mph).

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Average humidity in September
Modesto, CA

Average humidity in September - Modesto, CA
  • Average humidity in September: 41%

The month with the highest relative humidity is January (72%).
The month with the lowest relative humidity is July (37%).

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Average rainfall in September
Modesto, CA

Average rainfall in September - Modesto, CA
  • Average rainfall in September: 0.08"

The wettest month (with the highest rainfall) is March (1.3").
The driest months (with the least rainfall) are July and August (0.04").

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Average rainfall days in September
Modesto, CA

Average rainfall days in September - Modesto, CA
  • Average rainfall days in September: 1.6 days

The month with the highest number of rainy days is March (10.3 days).
The month with the least rainy days is August (0.9 days).

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

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

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

  • Average sunshine in September: 11h and 3min

The month with the most sunshine is July (Average sunshine: 12h and 6min).
The month with the least sunshine is December (Average sunshine: 6h and 0min).

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Average sunshine days in September
Modesto, CA

Average sunshine days in September - Modesto, CA
  • Average sunshine days in September: 27.1 days

The month with the most sunshine days is August (29.2 days).
The month with the least sunshine days is March (19.6 days).

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Average UV index in September
Modesto, CA

Average UV index in September - Modesto, 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, February, November and December (UV index 3).

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Average cloud cover in September
Modesto, CA

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

The month with the most cloud cover is March (Cloud cover 33).
The month with the least cloud cover is July (Cloud cover 4).

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Average visibility in September
Modesto, CA

Average visibility in September - Modesto, 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).

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Modesto, California, USA

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