September weather forecast
Lafayette, CA

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Weather in September

The first month of the autumn, September, is still a warm month in Lafayette, California, with an average temperature fluctuating between 79.5°F (26.4°C) and 56.8°F (13.8°C).

Temperature

Lafayette transitions into September recording an average high-temperature of a still warm 79.5°F (26.4°C), closely aligning with the preceding month's temperature. Throughout September, Lafayette notes a dramatic plunge from the daily high to an average low-temperature of 56.8°F (13.8°C).

Humidity

In Lafayette, the average relative humidity in September is 61%.

Rainfall

In Lafayette, in September, it is raining for 2.8 days, with typically 0.12" (3mm) of accumulated precipitation. Throughout the year, there are 74.4 rainfall days, and 12.6" (320mm) of precipitation is accumulated.

Daylight

The average length of the day in September in Lafayette is 12h and 25min.
On the first day of September, 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.

Sunshine

In September, the average sunshine is 11.1h.

UV index

In Lafayette, the average daily maximum UV index in September is 5. A UV Index of 3 to 5 symbolizes a moderate health risk from unprotected exposure to Sun's UV rays for average individuals.
Note: In September, the maximum UV index of 5 suggests this advice:
Take necessary precautions - Protection from skin and eye injury is mandatory. It's recommended to limit sun exposure when its radiation is at its peak during midday. During bright days, sunglasses that offer UVA and UVB defense are recommended.
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Frequently asked questions

What are the temperatures in Lafayette in September?

In September, the average high-temperature and low-temperature in Lafayette are 79.5°F (26.4°C) and 56.8°F (13.8°C) respectively.

What is the average humidity in September in Lafayette?

The average relative humidity in September in Lafayette is 61%.

How many days does it rain in September in Lafayette?

In Lafayette, California, in September, during 2.8 rainfall days, 0.12" (3mm) of precipitation is typically accumulated.

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

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

What time are sunrise and sunset in September in Lafayette?

On the first day of September in Lafayette, California, 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 Lafayette have in September?

In September, the average sunshine duration in Lafayette, California, is 11.1h.

How high is the UV index in September in Lafayette?

In September, the average daily maximum UV index in Lafayette, California, is 5. A UV Index estimate of 3 to 5 represents a medium health risk from unprotected exposure to UV radiation.
Average humidity
Average rainfall days
Average daylight
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in September
Lafayette, CA

Average temperature in September - Lafayette, CA
  • Average high temperature in September: 79.5°F

The warmest month (with the highest average high temperature) is July (80.1°F).
The month with the lowest average high temperature is December (55.2°F).

  • Average low temperature in September: 56.8°F

The months with the highest average low temperature are August and September (56.8°F).
The coldest month (with the lowest average low temperature) is January (43.3°F).

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Average pressure in September
Lafayette, CA

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

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

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Average wind speed in September
Lafayette, CA

Average wind speed in September - Lafayette, CA
  • Average wind speed in September: 5.5mph

The windiest month (with the highest average wind speed) is May (7.2mph).
The calmest month (with the lowest average wind speed) is November (4.6mph).

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Average humidity in September
Lafayette, CA

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

The month with the highest relative humidity is March (74%).
The month with the lowest relative humidity is October (60%).

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Average rainfall in September
Lafayette, CA

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

The wettest month (with the highest rainfall) is February (2.6").
The driest months (with the least rainfall) are July and August (0.04").

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Average rainfall days in September
Lafayette, CA

Average rainfall days in September - Lafayette, CA
  • Average rainfall days in September: 2.8 days

The month with the highest number of rainy days is March (13.1 days).
The month with the least rainy days is August (0.8 days).

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

Average daylight in September / Average sunshine in September - Lafayette, 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 0min).
The month with the least sunshine is December (Average sunshine: 5h and 48min).

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Average sunshine days in September
Lafayette, CA

Average sunshine days in September - Lafayette, CA
  • Average sunshine days in September: 25.9 days

The month with the most sunshine days is August (27.8 days).
The month with the least sunshine days is March (16.3 days).

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Average UV index in September
Lafayette, CA

Average UV index in September - Lafayette, 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).

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Average cloud cover in September
Lafayette, CA

Average cloud cover in September - Lafayette, CA
  • Average cloud cover in September: 11

The month with the most cloud cover is March (Cloud cover 36).
The month with the least cloud cover is July (Cloud cover 8).

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Average visibility in September
Lafayette, CA

Average visibility in September - Lafayette, 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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Lafayette, California, USA

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