September weather forecast and climate
La Jolla, CA

Weather in September

September, the first month of the autumn, in La Jolla, is still a warm month, with average temperature ranging between min 64.4°F (18°C) and max 78.6°F (25.9°C).

Temperature

In La Jolla, the average high-temperature is almost the same as in August - a still warm 78.6°F (25.9°C). In September, in La Jolla, the average low-temperature is 64.4°F (18°C).

Humidity

In La Jolla, California, the average relative humidity is 65%.

Rainfall

In La Jolla, in September, it is raining for 4.2 days, with typically 0.31" (8mm) of accumulated precipitation. Throughout the year, in La Jolla, California, there are 57.9 rainfall days, and 7.48" (190mm) of precipitation is accumulated.

Ocean temperature

In La Jolla, the average water temperature is 66.7°F (19.3°C).
Note: For most, swimming in 66.7°F (19.3°C) is not an enjoyable activity. Furthermore, controlling your breathing becomes progressively more difficult as the water temperature decreases from 69.8°F (21°C) to 59°F (15°C).

Daylight

In La Jolla, California, the average length of the day is 12.4h.

Sunshine

In La Jolla, the average sunshine is 10.3h.

UV index

July through September, with an average maximum UV index of 6, are months with the highest UV index in La Jolla. A UV Index of 6 to 7 symbolizes a high health risk from the exposure to the Sun's UV rays for average individuals.
Note: The daily maximum UV index of 6 in September interpret into the following advice:
Take precautions and adopt sun safety practices. Protection against sunburn is obliged. The Sun's UV radiation is most powerful between 10 a.m. and 4 p.m. To the extent possible, limit exposure to the direct sun during these hours. Sun-protective clothing, a long-sleeved shirt and pants, a wide-brimmed hat, and UVA and UVB-blocking sunglasses are particularly helpful in blocking UV radiation's harmful effects.
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FAQ

What is the temperature in September in La Jolla?

In September, in La Jolla, the average high-temperature is 78.6°F (25.9°C), and the average low-temperature is 64.4°F (18°C).

What is the average humidity in September in La Jolla?

In September, the average relative humidity in La Jolla is 65%.

How much does it rain in La Jolla in September?

In La Jolla, California, in September, during 4.2 rainfall days, 0.31" (8mm) of precipitation is typically accumulated.

What is the ocean temperature in September in La Jolla?

In La Jolla, in September, the average water temperature is 66.7°F (19.3°C). For most, swimming in 66.7°F (19.3°C) is not an enjoyable activity. Furthermore, controlling your breathing becomes progressively more difficult as the water temperature decreases from 69.8°F (21°C) to 59°F (15°C).

How many hours of daylight does La Jolla have in September?

In La Jolla, California, the average length of the day in September is 12.4h.

How long on average sun shines in September in La Jolla?

In September, the average sunshine in La Jolla is 10.3h.

What are the months with the highest UV index in La Jolla?

July through September, with an average maximum UV index of 6, are months with the highest UV index in La Jolla, California.

How high is the UV index in September in La Jolla?

In September, the average daily maximum UV index is 6. A UV Index of 6 to 7 symbolizes a high hazard to health from the exposure to the Sun's UV rays.

Average temperature in September
La Jolla, CA

Average temperature in September - La Jolla, CA
  • Average high temperature in September: 78.6°F

The warmest month (with the highest average high temperature) is August (79.3°F).
The month with the lowest average high temperature is December (63.5°F).

  • Average low temperature in September: 64.4°F

The month with the highest average low temperature is August (65.8°F).
The coldest month (with the lowest average low temperature) is February (50.2°F).

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Average pressure in September
La Jolla, CA

Average pressure in September - La Jolla, CA
  • Average pressure in September: 29.88"

The month with the highest atmospheric pressure is January (30.09").
Months with the lowest atmospheric pressure are June and September (29.88").

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Average wind speed in September
La Jolla, CA

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

The windiest month (with the highest average wind speed) is April (6mph).
The calmest month (with the lowest average wind speed) is October (4.8mph).

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Average humidity in September
La Jolla, CA

Average humidity in September - La Jolla, CA
  • Average humidity in September: 65%

Months with the highest relative humidity are May and June (71%).
The month with the lowest relative humidity is November (57%).

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Average rainfall in September
La Jolla, CA

Average rainfall in September - La Jolla, CA
  • Average rainfall in September: 0.31"

The wettest month (with the highest rainfall) is February (1.46").
The driest month (with the least rainfall) is June (0.12").

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Average rainfall days in September
La Jolla, CA

Average rainfall days in September - La Jolla, CA
  • Average rainfall days in September: 4.2 days

The month with the highest number of rainy days is March (7.1 days).
The month with the least rainy days is June (2.2 days).

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Average sea temperature in September
La Jolla, CA

Average sea temperature in September - La Jolla, CA
  • Average sea temperature in September: 66.7°F

The best month for swimming (with the highest average sea temperature) is August (67.9°F).
The coldest month (with the lowest average sea temperature) is February (58.7°F).

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Average daylight in September /
Average sunshine in September
La Jolla, CA

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

The month with the longest days is June (Average daylight: 14.3h).
The month with the shortest days is December (Average daylight: 10h).

  • Average sunshine in September: 10.3h

The month with the most sunshine is July (Average sunshine: 12h).
The month with the least sunshine is December (Average sunshine: 6.8h).

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Average sunshine days in September
La Jolla, CA

Average sunshine days in September - La Jolla, CA
  • Average sunshine days in September: 22.4 days

The month with the most sunshine days is January (24.8 days).
The month with the least sunshine days is February (20.2 days).

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Average UV index in September
La Jolla, CA

Average UV index in September - La Jolla, CA
  • Average UV index in September: 6

Months with the highest UV index are July, August and September (UV index 6).
Months with the lowest UV index are January, February, March, November and December (UV index 4).

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Average cloud cover in September
La Jolla, CA

Average cloud cover in September - La Jolla, CA
  • Average cloud cover in September: 11

Months with the most cloud cover are March and December (Cloud cover 23).
The month with the least cloud cover is August (Cloud cover 8).

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Average visibility in September
La Jolla, CA

Average visibility in September - La Jolla, 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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