September weather forecast and climate
Hayward, CA

The landscape of the famed Verdant Hills in Hayward, California
The landscape of the famed Verdant Hills in Hayward, California

Weather in September

September, the first month of the autumn, in Hayward, is also a moderately hot month, with temperature in the range of an average high of 79°F (26.1°C) and an average low of 56.3°F (13.5°C).

Temperature

In Hayward, the average high-temperature in September is relatively the same as in August - a still moderately hot 79°F (26.1°C). The average low-temperature, in Hayward, is 56.3°F (13.5°C).

Humidity

September is the least humid month in Hayward, California, with an average relative humidity of 61%.

Rainfall

In Hayward, California, in September, it is raining for 2.1 days, with typically 0.12" (3mm) of accumulated precipitation. In Hayward, during the entire year, the rain falls for 69.2 days and collects up to 11.1" (282mm) of precipitation.

Daylight

In September, the average length of the day in Hayward is 12.4h.

Sunshine

In Hayward, California, the average sunshine is 11.1h.

UV index

In September, the average daily maximum UV index is 5. A UV Index estimate of 3 to 5 represents a medium vulnerability from unprotected exposure to the Sun's UV rays for average individuals.
Note: The average daily UV index of 5 transform into the following instructions:
Take precautions - Protection against sunburn is recommended. The solar radiation is most powerful near the mid-day, so the exposure to the direct Sun should be reduced accordingly. 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

What is the temperature in September in Hayward?

In September, in Hayward, the average high-temperature is 79°F (26.1°C), and the average low-temperature is 56.3°F (13.5°C).

What is the least humid month in Hayward?

September is the least humid month, with an average relative humidity of 61%.

What is the average humidity in September in Hayward?

The average relative humidity in September is 61%.

How many days does it rain in September in Hayward?

In September, the rain falls for 2.1 days. Throughout September, 0.12" (3mm) of precipitation is accumulated.

What is the average length of the day in September in Hayward?

In September, the average length of the day in Hayward is 12.4h.

How long on average sun shines in September in Hayward?

The average sunshine in September in Hayward is 11.1h.

How high is the UV index in September in Hayward?

In September, the average daily maximum UV index is 5. A UV Index reading of 3 to 5 represents a medium health risk from the exposure to the Sun's UV radiation.

Average temperature in September
Hayward, CA

Average temperature in September - Hayward, CA
  • Average high temperature in September: 79°F

The warmest month (with the highest average high temperature) is July (80.2°F).
The month with the lowest average high temperature is December (55.9°F).

  • Average low temperature in September: 56.3°F

The month with the highest average low temperature is August (56.5°F).
The coldest months (with the lowest average low temperature) are January and December (43.7°F).

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Average pressure in September
Hayward, CA

Average pressure in September - Hayward, CA
  • Average pressure in September: 29.92"

The month with the highest atmospheric pressure is January (30.14").
Months with the lowest atmospheric pressure are June, August and September (29.92").

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Average wind speed in September
Hayward, CA

Average wind speed in September - Hayward, CA
  • Average wind speed in September: 5mph

The windiest month (with the highest average wind speed) is May (6.6mph).
The calmest month (with the lowest average wind speed) is November (4.6mph).

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Average humidity in September
Hayward, CA

Average humidity in September - Hayward, CA
  • Average humidity in September: 61%

The month with the highest relative humidity is March (74%).
The month with the lowest relative humidity is September (61%).

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Average rainfall in September
Hayward, CA

Average rainfall in September - Hayward, CA
  • Average rainfall in September: 0.12"

The wettest month (with the highest rainfall) is February (2.28").
The driest months (with the least rainfall) are July and August (0.04").

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Average rainfall days in September
Hayward, CA

Average rainfall days in September - Hayward, CA
  • Average rainfall days in September: 2.1 days

The month with the highest number of rainy days is March (12.4 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
Hayward, CA

Average daylight in September / Average sunshine in September - Hayward, CA
  • Average daylight in September: 12.4h

The month with the longest days is June (Average daylight: 14.7h).
The month with the shortest days is December (Average daylight: 9.6h).

  • Average sunshine in September: 11.1h

The month with the most sunshine is July (Average sunshine: 12.1h).
The month with the least sunshine is December (Average sunshine: 5.9h).

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Average sunshine days in September
Hayward, CA

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

The month with the most sunshine days is August (28.9 days).
The month with the least sunshine days is March (17.3 days).

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Average UV index in September
Hayward, CA

Average UV index in September - Hayward, CA
  • Average UV index in September: 5

The month with the highest UV index is June (UV index 6).
Months with the lowest UV index are January, February, November and December (UV index 3).

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Average cloud cover in September
Hayward, CA

Average cloud cover in September - Hayward, CA
  • Average cloud cover in September: 10

Months with the most cloud cover are March and December (Cloud cover 34).
The month with the least cloud cover is July (Cloud cover 7).

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Average visibility in September
Hayward, CA

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

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

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