September weather forecast and climate
Rancho Bernardo, CA

Weather in September

September, the first month of the autumn, in Rancho Bernardo, is also a moderately hot month, with temperature in the range of an average low of 63.1°F (17.3°C) and an average high of 82.6°F (28.1°C).

Temperature

In Rancho Bernardo, the average high-temperature in September is essentially the same as in August - a still moderately hot 82.6°F (28.1°C). In September, the average low-temperature is 63.1°F (17.3°C).

Heat index

The average heat index is appraised at 85.3°F (29.6°C). Constant exposure and activity lead to possible fatigue. Prolonged exercise may result in heat cramps.
Note that heat index values are valued for light wind and location in the shade. Exposure to direct sunshine can increase heat index values by up to 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'apparent temperature', 'feels like', 'felt air temperature', or 'real feel', is a measure of how hot it feels when the actual air humidity is factored in. Additional factors like activity, metabolic differences, wind, and pregnancy affect individual temperature impact. Bear in mind that direct sunshine exposure increases weather impact, and may raise heat index by up to 15 Fahrenheit (8 Celsius) degrees. Heat index values are especially crucial for babies and toddlers. Young children are generally more endangered than adults, as they usually less sweat. And also, due to larger skin surface relative to their small bodies and higher heat production as a result of their activity.

Humidity

The average relative humidity in Rancho Bernardo is 60%.

Rainfall

In Rancho Bernardo, during September, the rain falls for 3.8 days and regularly aggregates up to 0.31" (8mm) of precipitation. In Rancho Bernardo, during the entire year, the rain falls for 54.7 days and collects up to 8.15" (207mm) of precipitation.

Daylight

In September, the average length of the day is 12.4h.

Sunshine

In September, the average sunshine is 10.3h.

UV index

June through September, with an average maximum UV index of 6, are months with the highest UV index in Rancho Bernardo. A UV Index value of 6 to 7 symbolizes a high threat to health from unprotected exposure to the Sun's UV rays for average individuals.
Note: The average daily UV index of 6 in September transform into the following instructions:
Take precautions against overexposure. Protection against sun damage is needed. 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. A wide-brim hat offers excellent sun protection for eyes, ears, face, and neck. Sunglasses with UVA and UVB protection significantly reduce eye damage from sun exposure. Tightly woven, loose-fitting clothes provide additional protection from the Sun.
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FAQ

What is the temperature in September in Rancho Bernardo?

In September, the average high-temperature is 82.6°F (28.1°C), and the average low-temperature is 63.1°F (17.3°C). In September, the average heat index (a.k.a. 'apparent temperature', 'real feel'), that represents influence of the relative humidity to air temperaure, is appraised at 85.3°F (29.6°C).

What is the average humidity in September in Rancho Bernardo?

In September, the average relative humidity in Rancho Bernardo, California, is 60%.

How many days does it rain in September in Rancho Bernardo?

In Rancho Bernardo, in September, during 3.8 rainfall days, 0.31" (8mm) of precipitation is typically accumulated.

How many hours of daylight does Rancho Bernardo have in September?

In September, the average length of the day is 12.4h.

How long on average sun shines in September in Rancho Bernardo?

In Rancho Bernardo, California, the average sunshine in September is 10.3h.

When is the highest UV index in Rancho Bernardo?

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

What is the UV index intensity in September in Rancho Bernardo?

In Rancho Bernardo, 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 unsafe exposure to the Sun's UV rays.

Average temperature in September
Rancho Bernardo, CA

Average temperature in September - Rancho Bernardo, CA
  • Average high temperature in September: 82.6°F

The warmest month (with the highest average high temperature) is August (84.2°F).
The month with the lowest average high temperature is December (63.9°F).

  • Average low temperature in September: 63.1°F

The month with the highest average low temperature is August (64.4°F).
The coldest month (with the lowest average low temperature) is February (47.1°F).

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Average pressure in September
Rancho Bernardo, CA

Average pressure in September - Rancho Bernardo, CA
  • Average pressure in September: 29.87"

The month with the highest atmospheric pressure is January (30.09").
Months with the lowest atmospheric pressure are June and September (29.87").

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Average wind speed in September
Rancho Bernardo, CA

Average wind speed in September - Rancho Bernardo, CA
  • Average wind speed in September: 4.3mph

The windiest month (with the highest average wind speed) is April (5.5mph).
The calmest months (with the lowest average wind speed) are September and October (4.3mph).

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Average humidity in September
Rancho Bernardo, CA

Average humidity in September - Rancho Bernardo, CA
  • Average humidity in September: 60%

The month with the highest relative humidity is May (68%).
The month with the lowest relative humidity is November (54%).

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Average rainfall in September
Rancho Bernardo, CA

Average rainfall in September - Rancho Bernardo, CA
  • Average rainfall in September: 0.31"

The wettest month (with the highest rainfall) is February (1.61").
The driest month (with the least rainfall) is June (0.08").

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Average rainfall days in September
Rancho Bernardo, CA

Average rainfall days in September - Rancho Bernardo, CA
  • Average rainfall days in September: 3.8 days

The month with the highest number of rainy days is March (7.2 days).
The month with the least rainy days is June (1.6 days).

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Average daylight in September /
Average sunshine in September
Rancho Bernardo, CA

Average daylight in September / Average sunshine in September - Rancho Bernardo, 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).
Months with the least sunshine are January and December (Average sunshine: 6.7).

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Average sunshine days in September
Rancho Bernardo, CA

Average sunshine days in September - Rancho Bernardo, CA
  • Average sunshine days in September: 23.9 days

The month with the most sunshine days is June (27 days).
The month with the least sunshine days is February (21.2 days).

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Average UV index in September
Rancho Bernardo, CA

Average UV index in September - Rancho Bernardo, CA
  • Average UV index in September: 6

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

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Average cloud cover in September
Rancho Bernardo, CA

Average cloud cover in September - Rancho Bernardo, CA
  • Average cloud cover in September: 10

The month with the most cloud cover is March (Cloud cover 24).
The month with the least cloud cover is August (Cloud cover 7).

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Average visibility in September
Rancho Bernardo, CA

Average visibility in September - Rancho Bernardo, 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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