September weather forecast
San Lorenzo, CA

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Weather in September

The first month of the autumn, September, is also a moderately hot month in San Lorenzo, California, with an average temperature fluctuating between 56.5°F (13.6°C) and 78.3°F (25.7°C).

Temperature

San Lorenzo registers an average high-temperature of a still warm 78.3°F (25.7°C) with the arrival of September, showing minor deviation from the preceding month. San Lorenzo registers a pronounced decline from daytime peak temperatures, averaging a mild 56.5°F (13.6°C) lows in September.

Humidity

September is the least humid month, with an average relative humidity of 62%.

Rainfall

In San Lorenzo, during September, the rain falls for 2.1 days and regularly aggregates up to 0.08" (2mm) of precipitation. In San Lorenzo, during the entire year, the rain falls for 56.9 days and collects up to 4.06" (103mm) of precipitation.

Daylight

The average length of the day in September is 12h and 25min.
On the first day of the month, sunrise is at 6:39 am and sunset at 7:37 pm. On the last day of September, sunrise is at 7:03 am and sunset at 6:52 pm PDT.

Sunshine

In September, the average sunshine is 11.1h.

UV index

The average daily maximum UV index in September is 5. A UV Index of 3 to 5 symbolizes a medium vulnerability from unsafe exposure to UV radiation for the ordinary person.
Note: The daily high UV index of 5 during September translates into the following recommendations:
Be vigilant - Preventing sunburn is recommended. Solar radiation is at its peak intensity during midday, so it's advisable to stay indoors or in the shade. For minimizing sun-related eye damage, always choose sunglasses with UVA and UVB coverage.

Frequently asked questions

What is the average September temperature?

San Lorenzo in September has an average high-temperature of 78.3°F (25.7°C) and an average low-temperature of 56.5°F (13.6°C).

What is the least humid month?

With an average relative humidity of 62%, September is the least humid month.

What is the average humidity in September in San Lorenzo?

The average relative humidity in September is 62%.

How many days does it rain in September?

In San Lorenzo, in September, during 2.1 rainfall days, 0.08" (2mm) of precipitation is typically accumulated.

How many hours of daylight does San Lorenzo have in September?

In September, the average day length is 12h and 25min.

What time are sunrise and sunset in September?

In September, on the first day of the month, sunrise is at 6:39 am and sunset at 7:37 pm. On the last day of the month, sunrise is at 7:03 am and sunset at 6:52 pm PDT.

How many hours of sunshine does San Lorenzo have in September?

In September, the average sunshine duration is 11.1h.

What is the UV index reading in September?

In September, the average daily maximum UV index is 5. A UV Index value of 3 to 5 symbolizes a medium health risk 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
San Lorenzo, CA

Average temperature in September - San Lorenzo, CA
  • Average high temperature in September: 78.3°F

The warmest month (with the highest average high temperature) is July (79.2°F).
The month with the lowest average high temperature is December (56.1°F).

  • Average low temperature in September: 56.5°F

The month with the highest average low temperature is September (56.5°F).
The coldest months (with the lowest average low temperature) are January and December (44.1°F).

Average pressure in September
San Lorenzo, CA

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

The month with the highest atmospheric pressure is January (30.13"Hg).
The months with the lowest atmospheric pressure are June, August and September (29.92"Hg).

Average wind speed in September
San Lorenzo, CA

Average wind speed in September - San Lorenzo, CA
  • Average wind speed in September: 5.1mph

The windiest month (with the highest average wind speed) is May (6.7mph).
The calmest month (with the lowest average wind speed) is November (4.7mph).

Average humidity in September
San Lorenzo, CA

Average humidity in September - San Lorenzo, CA
  • Average humidity in September: 62%

The month with the highest relative humidity is March (74%).
The month with the lowest relative humidity is September (62%).

Average rainfall in September
San Lorenzo, CA

Average rainfall in September - San Lorenzo, CA
  • Average rainfall in September: 0.08"

The wettest month (with the highest rainfall) is February (0.87").
The driest months (with the least rainfall) are June, July and August (0.04").

Average rainfall days in September
San Lorenzo, CA

Average rainfall days in September - San Lorenzo, CA
  • Average rainfall days in September: 2.1 days

The month with the highest number of rainy days is March (10.5 days).
The month with the least rainy days is August (0.7 days).

Average daylight in September /
Average sunshine in September
San Lorenzo, CA

Average daylight in September / Average sunshine in September - San Lorenzo, 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 1min

The month with the most sunshine is July (Average sunshine: 12h and 6min).
The month with the least sunshine is December (Average sunshine: 5h and 54min).

Average sunshine days in September
San Lorenzo, CA

Average sunshine days in September - San Lorenzo, CA
  • Average sunshine days in September: 26.9 days

The month with the most sunshine days is July (27.9 days).
The month with the least sunshine days is March (18.6 days).

Average UV index in September
San Lorenzo, CA

Average UV index in September - San Lorenzo, CA
  • Average UV index in September: 5

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

Average cloud cover in September
San Lorenzo, CA

Average cloud cover in September - San Lorenzo, CA
  • Average cloud cover in September: 10

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

Average visibility in September
San Lorenzo, CA

Average visibility in September - San Lorenzo, 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).

San Lorenzo, California, USA

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