September weather forecastSan Ramon, CA
September
Weather in September
The first month of the autumn, September, is still a warm month in San Ramon, California, with temperature in the range of an average low of 56.5°F (13.6°C) and an average high of 82°F (27.8°C).Temperature
San Ramon observes an average high-temperature of a still warm 82°F (27.8°C) in September, barely different from 83.3°F (28.5°C) in August. San Ramon logs a notable disparity from the daily highs during September, as the nighttime temperature lowers to an average of 56.5°F (13.6°C).Heat index
The heat index value during September is estimated at 84.2°F (29°C). If one endures exposure and continues to be active, it might result in tiredness and heat cramps.Take into consideration that the heat index values are calculated for shade and light wind conditions. If directly exposed to the sun, the heat index could rise by 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'feels like' or 'real feel', is a numerical representation of warmth when taking temperature and moisture levels into account. Elements such as metabolic variations, being pregnant, and physical activity can impact one's weather perception. In the direct sunlight, the weather's impact can be amplified, possibly boosting the heat index by up to 15 Fahrenheit (8 Celsius) degrees. Heat index values are extremely significant for babies and toddlers. Children often fail to recognize the requirement to rest and rehydrate. Thirst, being a late symptom of dehydration, underlines the importance of maintaining hydration, especially during ongoing physical activities.
Humidity
The least humid month is September, with an average relative humidity of 57%.Rainfall
In San Ramon, during September, the rain falls for 1.8 days and regularly aggregates up to 0.08" (2mm) of precipitation. In San Ramon, during the entire year, the rain falls for 67.2 days and collects up to 10.98" (279mm) of precipitation.Daylight
The average length of the day in September is 12h and 25min.On the first day of the month, sunrise is at 6:38 am and sunset at 7:36 pm. On the last day of September, in San Ramon, sunrise is at 7:03 am and sunset at 6:51 pm PDT.
Sunshine
In September, the average sunshine is 11.2h.UV index
The average daily maximum UV index in September is 5. A UV Index reading of 3 to 5 represents a moderate health risk from exposure to the Sun's UV rays for average individuals.Note: A daily high UV index of 5 in September leads to these guidelines:
Proceed with care. Light skin individuals may be exposed to burns in fewer than 30 minutes. Avoiding the Sun's peak radiation during midday hours is essential for health and safety. For a sun-safe wardrobe, go for clothes that are tightly woven and generously sized.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
San Ramon, CA
- Average high temperature in September: 82°F
The warmest month (with the highest average high temperature) is July (83.7°F).
The month with the lowest average high temperature is December (55.9°F).
- Average low temperature in September: 56.5°F
The month with the highest average low temperature is September (56.5°F).
The coldest month (with the lowest average low temperature) is December (42.1°F).
Average pressure in September
San Ramon, CA
- Average pressure in September: 29.92"Hg
The month with the highest atmospheric pressure is January (30.14"Hg).
The months with the lowest atmospheric pressure are June, August and September (29.92"Hg).
Average wind speed in September
San Ramon, CA
- Average wind speed in September: 5.2mph
The windiest month (with the highest average wind speed) is May (6.7mph).
The calmest month (with the lowest average wind speed) is November (4.2mph).
Average humidity in September
San Ramon, CA
- Average humidity in September: 57%
The month with the highest relative humidity is March (74%).
The month with the lowest relative humidity is September (57%).
Average rainfall in September
San Ramon, CA
- Average rainfall in September: 0.08"
The wettest month (with the highest rainfall) is February (2.28").
The driest month (with the least rainfall) is July (0").
Average rainfall days in September
San Ramon, CA
- Average rainfall days in September: 1.8 days
The month with the highest number of rainy days is March (12.6 days).
The month with the least rainy days is August (0.6 days).
Average daylight in September /
Average sunshine in September
San Ramon, CA
- Average daylight in September: 12h and 24min
The month with the longest days is June (Average daylight: 14h and 42min).
The month with the shortest days is December (Average daylight: 9h and 36min).
- Average sunshine in September: 11h and 12min
The month with the most sunshine is July (Average sunshine: 12h and 6min).
The month with the least sunshine is December (Average sunshine: 5h and 48min).
Average sunshine days in September
San Ramon, CA
- Average sunshine days in September: 27.5 days
The month with the most sunshine days is July (29.9 days).
The month with the least sunshine days is March (17.5 days).
Average UV index in September
San Ramon, CA
- Average UV index in September: 5
The months with the highest UV index are June, July and August (UV index 6).
The months with the lowest UV index are January, February, November and December (UV index 3).
Average cloud cover in September
San Ramon, CA
- Average cloud cover in September: 10
The month with the most cloud cover is March (Cloud cover 36).
The month with the least cloud cover is July (Cloud cover 6).
Average visibility in September
San Ramon, 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).
