September weather forecast
Los Angeles, CA

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A beautiful view of the detailed layout of Los Angeles in California, USA
A beautiful view of the detailed layout of Los Angeles in California, USA

Weather in September

September in Los Angeles, California, observes a shift from the intense summer weather to the moderately warm autumn season. Despite the decrease in daylight hours, the average temperature refuses to lower significantly, keeping the days quite warm. It is observed that the cloud cover in September increases to 9% from August's 6%, attempting to tame the striking summer sun. All the while, the wind speeds remain nearly constant from August, maintaining the city's calm atmosphere. Therefore, September exemplifies the subtle onset of autumn, with the weather remaining significantly warm while gradually cooling down.

Temperature

The transition into September is marked with an average high-temperature of a still warm 82.2°F (27.9°C), showing an insignificant shift from August's 83.3°F (28.5°C). Throughout September, Los Angeles encounters an average temperature drop to an enjoyable 64.4°F (18°C).

Heat index

September's mean heat index is calculated to be 84.2°F (29°C). With prolonged exposure and constant activity, one might feel exhausted and experience heat cramps.
Heat index determinations are made taking into account the shade and light air movements. The presence of direct sunlight can raise the heat index values by up to 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'feels like' or 'real feel', shows a temperature sensation when both heat and moisture conditions are combined. One's weather perception can be influenced by a range of factors including metabolic differences, being pregnant, and their level of physical activity. One must note that being under the direct sun can escalate the heat's effects, with the heat index possibly rising by 15 Fahrenheit (8 Celsius) degrees. Heat index values are extremely significant for children. Young ones are generally at greater risk than adults due to their limited sweating ability. In addition, their large skin surface relative to their small bodies and higher heat production from their activities add to their vulnerability.

Humidity

In Los Angeles, the average relative humidity in September is 57%.

Rainfall

In Los Angeles, California, during September, the rain falls for 2.1 days and regularly aggregates up to 0.12" (3mm) of precipitation. Throughout the year, there are 44.6 rainfall days, and 8.11" (206mm) of precipitation is accumulated.

Daylight

The average length of the day in September is 12h and 22min.
On the first day of the month, sunrise is at 6:27 am and sunset at 7:18 pm. On the last day of September, sunrise is at 6:47 am and sunset at 6:38 pm PDT.

Sunshine

The average sunshine in September is 10.7h.

UV index

The months with the highest UV index are June through September, with an average maximum UV index of 6. A UV Index value of 6 to 7 symbolizes a high health hazard from unsafe exposure to UV radiation for ordinary individuals.
Note: A daily high UV index of 6 in September leads to these guidelines:
Take precautions and utilize sun safety practices. Protection against skin and eye damage is required. UV radiation from the Sun is most intense between 10 a.m. and 4 p.m. Try to avoid direct sunlight during this period. Employ a hat with a wide brim for robust protection, cutting UV exposure by half.
Updated: Jun 30, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What are September temperatures?

In Los Angeles, in September, the average high-temperature is 82.2°F (27.9°C), and the average low-temperature is 64.4°F (18°C). The average heat index (a.k.a. 'real feel', 'feels like'), which takes the relative humidity and factors it into the air temperature reading, in September is calculated to be 84.2°F (29°C).

What is the average humidity in September?

In Los Angeles, the average relative humidity in September is 57%.

How many days does it rain in September?

In Los Angeles, during September, the rain falls for 2.1 days and regularly aggregates up to 0.12" (3mm) of precipitation.

How many hours of daylight does Los Angeles have in September?

In September, the average day length is 12h and 22min.

What time are sunrise and sunset in September?

In September, on the first day of the month, sunrise is at 6:27 am and sunset at 7:18 pm. On the last day of the month, sunrise is at 6:47 am and sunset at 6:38 pm PDT.

How long on average sun shines in September?

The average sunshine duration in September is 10.7h.

What is the month with the highest UV index?

June through September, with an average maximum UV index of 6, are months with the highest UV index.

What is the UV index reading in September?

The average daily maximum UV index in September is 6. A UV Index estimate of 6 to 7 represents a high health risk from exposure to the Sun's 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
Los Angeles, CA

Average temperature in September - Los Angeles, CA
  • Average high temperature in September: 82.2°F

The warmest month (with the highest average high temperature) is August (83.3°F).
The month with the lowest average high temperature is December (64°F).

  • Average low temperature in September: 64.4°F

The month with the highest average low temperature is August (64.9°F).
The coldest month (with the lowest average low temperature) is February (49.8°F).

Average pressure in September
Los Angeles, CA

Average pressure in September - Los Angeles, CA
  • Average pressure in September: 29.89"Hg

The month with the highest atmospheric pressure is January (30.1"Hg).
The months with the lowest atmospheric pressure are June and September (29.89"Hg).

Average wind speed in September
Los Angeles, CA

Average wind speed in September - Los Angeles, CA
  • Average wind speed in September: 4.7mph

The windiest month (with the highest average wind speed) is April (6.1mph).
The calmest month (with the lowest average wind speed) is October (4.5mph).

Average humidity in September
Los Angeles, CA

Average humidity in September - Los Angeles, CA
  • Average humidity in September: 57%

The month with the highest relative humidity is June (65%).
The month with the lowest relative humidity is November (50%).

Average rainfall in September
Los Angeles, CA

Average rainfall in September - Los Angeles, CA
  • Average rainfall in September: 0.12"

The wettest month (with the highest rainfall) is February (1.73").
The driest month (with the least rainfall) is June (0.04").

Average rainfall days in September
Los Angeles, CA

Average rainfall days in September - Los Angeles, CA
  • Average rainfall days in September: 2.1 days

The month with the highest number of rainy days is March (6.9 days).
The month with the least rainy days is June (1 days).

Average daylight in September /
Average sunshine in September
Los Angeles, CA

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

The month with the longest days is June (Average daylight: 14h and 24min).
The month with the shortest days is December (Average daylight: 9h and 54min).

  • Average sunshine in September: 10h and 4min

The months with the most sunshine are July and August (Average sunshine: 12h and 0min).
The month with the least sunshine is December (Average sunshine: 6h and 42min).

Average sunshine days in September
Los Angeles, CA

Average sunshine days in September - Los Angeles, CA
  • Average sunshine days in September: 26.8 days

The month with the most sunshine days is August (28.1 days).
The month with the least sunshine days is February (21.7 days).

Average UV index in September
Los Angeles, CA

Average UV index in September - Los Angeles, CA
  • Average UV index in September: 6

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

Average cloud cover in September
Los Angeles, CA

Average cloud cover in September - Los Angeles, CA
  • Average cloud cover in September: 9

The months with the most cloud cover are March and December (Cloud cover 22).
The month with the least cloud cover is August (Cloud cover 6).

Average visibility in September
Los Angeles, CA

Average visibility in September - Los Angeles, 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).

Los Angeles, California, USA

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