September weather forecastKeyes, CA
September
Weather in September
September, the first month of the autumn in Keyes, is also a hot month, with an average temperature varying between 90.9°F (32.7°C) and 59.9°F (15.5°C).Temperature
Transitioning from August to September involves a subtle drop in average high-temperatures, descending from a torrid 96.4°F (35.8°C) to a hot 90.9°F (32.7°C). Despite the drastic temperature difference, Keyes records an average nighttime low of 59.9°F (15.5°C) throughout September.Heat index
The heat index value for September is computed to be a hot 93.2°F (34°C). Heightened precautions are necessary, heat cramps and heat exhaustion are potential risks. Continuous activity could lead to heatstroke.Take into consideration that the heat index values are calculated for shade and light wind conditions. Direct sunlight can potentially boost the heat index by 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'felt air temperature' or 'feels like', quantifies the warmth felt when relative humidity is considered. Elements such as metabolic variations, pregnancy, and physical exertion can shape one's weather perception. When exposed to direct sunlight, it's possible for the heat index to increase by as much as 15 Fahrenheit (8 Celsius) degrees. Heat index values are especially crucial for babies and toddlers. Children often do not understand the need to rest and hydrate. Thirst is a late manifestation of dehydration - therefore, it is essential to stay hydrated, particularly during prolonged physical activities.
Humidity
In September, the average relative humidity is 41%.Rainfall
In Keyes, during September, the rain falls for 1.6 days and regularly aggregates up to 0.08" (2mm) of precipitation. In Keyes, during the entire year, the rain falls for 54.3 days and collects up to 6.54" (166mm) of precipitation.Daylight
In Keyes, the average length of the day in September is 12h and 25min.On the first day of September, sunrise is at 6:34 am and sunset at 7:32 pm. On the last day of the month, sunrise is at 6:59 am and sunset at 6:47 pm PDT.
Sunshine
The average sunshine in September is 11.5h.UV index
In September, the average daily maximum UV index is 6. A UV Index estimate of 6 to 7 represents a high health risk from exposure to the Sun's UV radiation for ordinary individuals.Note: A maximum high UV index of 6 in September translates into the following recommendations:
Deflect overexposure. Sun protection is a necessity. From 10 a.m. to 4 p.m., when UV radiation is at its strongest, limit direct exposure to the Sun and note that shade structures may not provide full sun protection. Your best bet for sun defense on the face, eyes, and neck is a hat with a wide brim.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Keyes, CA
- Average high temperature in September: 90.9°F
The warmest month (with the highest average high temperature) is July (97.7°F).
The month with the lowest average high temperature is December (55.6°F).
- Average low temperature in September: 59.9°F
The month with the highest average low temperature is July (62.1°F).
The coldest months (with the lowest average low temperature) are January and December (41.9°F).
Average pressure in September
Keyes, CA
- Average pressure in September: 29.93"Hg
The month with the highest atmospheric pressure is January (30.15"Hg).
The month with the lowest atmospheric pressure is June (29.91"Hg).
Average wind speed in September
Keyes, CA
- Average wind speed in September: 5.8mph
The windiest month (with the highest average wind speed) is June (7.3mph).
The calmest month (with the lowest average wind speed) is November (5.2mph).
Average humidity in September
Keyes, CA
- Average humidity in September: 41%
The month with the highest relative humidity is January (72%).
The month with the lowest relative humidity is July (37%).
Average rainfall in September
Keyes, CA
- Average rainfall in September: 0.08"
The wettest month (with the highest rainfall) is March (1.3").
The driest months (with the least rainfall) are July and August (0.04").
Average rainfall days in September
Keyes, CA
- Average rainfall days in September: 1.6 days
The month with the highest number of rainy days is March (10.3 days).
The month with the least rainy days is August (0.9 days).
Average daylight in September /
Average sunshine in September
Keyes, 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 30min
The month with the most sunshine is July (Average sunshine: 12h and 6min).
The month with the least sunshine is December (Average sunshine: 6h and 0min).
Average sunshine days in September
Keyes, CA
- Average sunshine days in September: 27.1 days
The month with the most sunshine days is August (29.2 days).
The month with the least sunshine days is March (19.6 days).
Average UV index in September
Keyes, CA
- Average UV index in September: 6
The months with the highest UV index are June, July and August (UV index 7).
The months with the lowest UV index are January, February, November and December (UV index 3).
Average cloud cover in September
Keyes, CA
- Average cloud cover in September: 6
The month with the most cloud cover is March (Cloud cover 33).
The month with the least cloud cover is July (Cloud cover 4).
Average visibility in September
Keyes, 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).
