Contents
- Weather in September
- Frequently asked questions
- Average temperature in September
- Average pressure in September
- Average wind speed in September
- Average humidity in September
- Average rainfall in September
- Average rainfall days in September
- Average daylight in September
- Average sunshine in September
- Average sunshine days in September
- Average UV index in September
- Average cloud cover in September
- Average visibility in September
Weather in September
Temperature
The start of September marks an average high-temperature of a still moderately hot 82.6°F (28.1°C), hardly distinguishable from the conditions in August. September nights are marked by an average temperature drop to a refreshing 63.1°F (17.3°C).Heat index
September's mean heat index is appraised at a tropical 86°F (30°C). One might feel worn out with persistent exposure and activity, resulting in heat cramps.Given the heat index, its values are aligned with shaded sites and gentle winds. Heat index values may rise by up to 15 Fahrenheit (8 Celsius) degrees when exposed to direct sunlight.
Note: The heat index, also known as 'felt air temperature' or 'real feel', arises from combining readings of air temperature and relative moisture content. The influence of weather is personal, with a diverse population experiencing it differently due to differences in body mass, stature, and degree of activity. Exposure to direct sun rays can influence the heat you feel, pushing the heat index up by 15 Fahrenheit (8 Celsius) degrees. Heat index values are highly important for children. Children usually face more risks than adults as their ability to sweat is less. Additionally, their larger skin surface in relation to their petite bodies and higher heat output due to their activities increases their vulnerability.
Humidity
In September, the average relative humidity is 60%.Rainfall
In Rancho Bernardo, in September, during 3.8 rainfall days, 0.31" (8mm) of precipitation is typically accumulated. Throughout the year, there are 54.7 rainfall days, and 8.15" (207mm) of precipitation is accumulated.Daylight
In Rancho Bernardo, the average length of the day in September is 12h and 22min.On the first day of September, 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
The average sunshine in September in Rancho Bernardo is 10.3h.UV index
The months with the highest UV index are June through September, with an average maximum UV index of 6. A UV Index estimate of 6 to 7 represents a high health vulnerability from exposure to the Sun's UV rays for average individuals.Note: The UV index of 6 during September leads to these advisories:
Beware of overexposure. Fair-skinned individuals risk burning in less than 20 minutes. Limit your exposure to the sun's UV radiation, which is strongest between 10 a.m. and 4 p.m., and note that parasols or canopies may not provide full sun protection. Limit sun-induced ocular harm with sunglasses that feature UVA and UVB filtration.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
How hot is it in September?
What is the average humidity in September?
How much does it rain in September?
What is the average length of the day in September?
What time are sunrise and sunset in September?
How long on average sun shines in September in Rancho Bernardo?
What is the month with the highest UV index?
What is the UV index intensity in September?
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).
Average pressure in September
Rancho Bernardo, CA
- Average pressure in September: 29.87"Hg
The month with the highest atmospheric pressure is January (30.09"Hg).
The months with the lowest atmospheric pressure are June and September (29.87"Hg).
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).
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%).
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").
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).
Average daylight in September /
Average sunshine in September
Rancho Bernardo, 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 months with the least sunshine are January and December (Average sunshine: 6h and 42min).
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).
Average UV index in September
Rancho Bernardo, 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
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).
Average visibility in September
Rancho Bernardo, 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).
Rancho Bernardo, California, USA
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