September weather forecast
Chula Vista, CA

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Wood and rope barriers at sunset on the waterfront of Bayside Park in Chula Vista, San Diego Bay, California
Wood and rope barriers at sunset on the waterfront of Bayside Park in Chula Vista, San Diego Bay, California

Weather in September

September ushers Chula Vista into the autumn season with gradually declining temperatures. Compared to the city's scorching summer months, September's milder weather offers pleasant outdoor possibilities. Rainfall is relatively low at 0.28" (7mm), and skies remain largely clear. The city fashions a unique blend of lingering summer warmth, slowly folding into the cool embrace of autumn. Transitioning into this season, September carries a unique character, marking the beginnings of serene and quieter days.

Temperature

With the arrival of September, Chula Vista's average high-temperature registers at a still moderately hot 78.3°F (25.7°C), indicating a subtle variation from the previous month. In Chula Vista, September's nights observe an average temperature dip to an enjoyable 65.5°F (18.6°C).

Humidity

In September, the average relative humidity is 66%.

Rainfall

In Chula Vista, in September, during 3.5 rainfall days, 0.28" (7mm) of precipitation is typically accumulated. In Chula Vista, California, during the entire year, the rain falls for 51 days and collects up to 5.63" (143mm) of precipitation.

Ocean temperature

In Chula Vista, in September, the average water temperature is 66.7°F (19.3°C).
Note: Swimming becomes less enjoyable for most at a surface water temperature of 66.7°F (19.3°C). As the temperature decreases below 69.8°F (21°C), breathing becomes increasingly difficult.

Daylight

In September, the average length of the day in Chula Vista, California, is 12h and 22min.
On the first day of September in Chula Vista, California, sunrise is at 6:23 am and sunset at 7:12 pm. On the last day of the month, sunrise is at 6:42 am and sunset at 6:33 pm PDT.

Sunshine

In September, the average sunshine in Chula Vista is 10.3h.

UV index

The months with the highest UV index in Chula Vista are June through September, with an average maximum UV index of 6. A UV Index of 6 to 7 symbolizes a high health vulnerability from unsafe exposure to UV radiation for the ordinary person.
Note: The maximum daily UV index of 6 in September interprets into the following recommendations:
Endorse precautions and be consistent with sun safety guidelines. Preventing sunburn is paramount. UV radiation from the sun is at its strongest between 10 a.m. and 4 p.m. Try to limit direct exposure during these hours. Enhance your sun protection with tightly woven, yet airy clothing.
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Frequently asked questions

What is the usual temperature for Chula Vista in September?

The average high-temperature and low-temperature in Chula Vista during September are 78.3°F (25.7°C) and 65.5°F (18.6°C) respectively.

What is the average humidity in September in Chula Vista?

The average relative humidity in September in Chula Vista, California, is 66%.

How much does it rain in Chula Vista in September?

In Chula Vista, during September, the rain falls for 3.5 days and regularly aggregates up to 0.28" (7mm) of precipitation.

How cold is the water in September in Chula Vista?

In Chula Vista, California, the average seawater temperature in September 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 Chula Vista have in September?

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

When are sunrise and sunset in September in Chula Vista?

In September, on the first day of the month, sunrise is at 6:23 am and sunset at 7:12 pm. On the last day of the month, sunrise is at 6:42 am and sunset at 6:33 pm PDT.

How long on average sun shines in September in Chula Vista?

In Chula Vista, the average sunshine duration in September is 10.3h.

When is the highest UV index in Chula Vista?

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

What is the UV index intensity in September in Chula Vista?

In Chula Vista, California, the average daily maximum UV index in September is 6. A UV Index estimate of 6 to 7 represents a high hazard to health 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
Chula Vista, CA

Average temperature in September - Chula Vista, CA
  • Average high temperature in September: 78.3°F

The warmest month (with the highest average high temperature) is August (79.2°F).
The month with the lowest average high temperature is December (63.7°F).

  • Average low temperature in September: 65.5°F

The month with the highest average low temperature is August (66.7°F).
The coldest month (with the lowest average low temperature) is February (51.1°F).

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Average pressure in September
Chula Vista, CA

Average pressure in September - Chula Vista, CA
  • Average pressure in September: 29.88"Hg

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

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Average wind speed in September
Chula Vista, CA

Average wind speed in September - Chula Vista, CA
  • Average wind speed in September: 5.2mph

The windiest month (with the highest average wind speed) is April (6.2mph).
The calmest month (with the lowest average wind speed) is October (5mph).

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Average humidity in September
Chula Vista, CA

Average humidity in September - Chula Vista, CA
  • Average humidity in September: 66%

The month with the highest relative humidity is June (71%).
The month with the lowest relative humidity is November (58%).

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Average rainfall in September
Chula Vista, CA

Average rainfall in September - Chula Vista, CA
  • Average rainfall in September: 0.28"

The wettest month (with the highest rainfall) is February (1.1").
The driest month (with the least rainfall) is June (0.08").

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Average rainfall days in September
Chula Vista, CA

Average rainfall days in September - Chula Vista, CA
  • Average rainfall days in September: 3.5 days

The month with the highest number of rainy days is March (7.2 days).
The month with the least rainy days is June (1.7 days).

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Average sea temperature in September
Chula Vista, CA

Average sea temperature in September - Chula Vista, 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
Chula Vista, CA

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

The month with the longest days is June (Average daylight: 14h and 18min).
The month with the shortest days is December (Average daylight: 10h and 0min).

  • Average sunshine in September: 10h and 2min

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

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Average sunshine days in September
Chula Vista, CA

Average sunshine days in September - Chula Vista, CA
  • Average sunshine days in September: 24.8 days

The month with the most sunshine days is June (27.2 days).
The month with the least sunshine days is February (21.1 days).

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Average UV index in September
Chula Vista, CA

Average UV index in September - Chula Vista, 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, March, November and December (UV index 4).

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Average cloud cover in September
Chula Vista, CA

Average cloud cover in September - Chula Vista, CA
  • Average cloud cover in September: 12

The 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
Chula Vista, CA

Average visibility in September - Chula Vista, 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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Chula Vista, California, USA

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