September weather forecastWalnut Grove, CA
September
Weather in September
September, the first month of the autumn in Walnut Grove, is still a tropical month, with temperature in the range of an average low of 58.1°F (14.5°C) and an average high of 86.9°F (30.5°C).Temperature
Walnut Grove's average high-temperature in September sits at a still hot 86.9°F (30.5°C), showing little difference from the previous month. A marked drop from daytime peak temperatures to an average low-temperature of 58.1°F (14.5°C) is observed during the nights in September.Heat index
The heat index value for September is computed to be a tropical 89.6°F (32°C). Ongoing exposure and activity could lead to a state of exhaustion, with a chance of heat cramps.Research indicates the heat index considers values in shaded locales and with light winds. The heat index has the possibility to be enhanced by 15 Fahrenheit (8 Celsius) degrees when there is direct sun exposure.
Note: The heat index, also known as 'felt air temperature' or 'apparent temperature', is an amalgamation of air temperature and humidity to express the equivalent perceived temperature. The effect is experienced differently by individuals, hinging on unique characteristics such as body mass, stature, and level of activity. Should you be directly under the sun, anticipate a possible increase in the heat index by up to 15 Fahrenheit (8 Celsius) degrees. Heat index values are especially crucial for babies and toddlers. In general, children are more at risk than adults because they sweat less. Furthermore, the large skin surface compared to their small bodies and the high heat production due to their actions contribute to this vulnerability.
Humidity
With an average relative humidity of 49%, September is the least humid month in Walnut Grove.Rainfall
January through July, September through December are months with rainfall. September is the first month it rains. Throughout September, in the average 1.6 rainfall days, it receives 0.08" (2mm) of precipitation. Throughout the year, there are 68.7 rainfall days, and 11.18" (284mm) of precipitation is accumulated.Daylight
In Walnut Grove, the average length of the day in September is 12h and 25min.On the first day of September, sunrise is at 6:36 am and sunset at 7:35 pm. On the last day of the month, sunrise is at 7:01 am and sunset at 6:49 pm PDT.
Sunshine
In Walnut Grove, the average sunshine in September is 11.2h.UV index
In Walnut Grove, the average daily maximum UV index in September is 5. A UV Index estimate of 3 to 5 represents a medium health hazard from exposure to the Sun's UV rays for the average person.Note: The daily maximum UV index of 5 in September interprets into the following advice:
Undertake precautions - It is suggested to shield oneself from sunburn. Midday is when the Sun's radiation is strongest; avoid prolonged exposure during this time. Sun-related eye harm can be minimized with proper sunglasses offering UVA and UVB coverage.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Walnut Grove, CA
- Average high temperature in September: 86.9°F
The warmest month (with the highest average high temperature) is July (91°F).
The month with the lowest average high temperature is December (55°F).
- Average low temperature in September: 58.1°F
The month with the highest average low temperature is September (58.1°F).
The coldest month (with the lowest average low temperature) is January (41.5°F).
Average pressure in September
Walnut Grove, CA
- Average pressure in September: 29.92"Hg
The month with the highest atmospheric pressure is January (30.14"Hg).
The month with the lowest atmospheric pressure is June (29.91"Hg).
Average wind speed in September
Walnut Grove, CA
- Average wind speed in September: 5.9mph
The windiest month (with the highest average wind speed) is June (7.6mph).
The calmest month (with the lowest average wind speed) is November (4.7mph).
Average humidity in September
Walnut Grove, CA
- Average humidity in September: 49%
The months with the highest relative humidity are January and March (74%).
The month with the lowest relative humidity is September (49%).
Average rainfall in September
Walnut Grove, CA
- Average rainfall in September: 0.08"
The wettest month (with the highest rainfall) is February (2.17").
The driest month (with the least rainfall) is August (0").
Average rainfall days in September
Walnut Grove, CA
- Average rainfall days in September: 1.6 days
The month with the highest number of rainy days is March (13 days).
The month with the least rainy days is August (0.7 days).
Average daylight in September /
Average sunshine in September
Walnut Grove, CA
- Average daylight in September: 12h and 24min
The month with the longest days is June (Average daylight: 14h and 48min).
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 54min).
Average sunshine days in September
Walnut Grove, CA
- Average sunshine days in September: 27.7 days
The month with the most sunshine days is August (29.9 days).
The month with the least sunshine days is March (17.3 days).
Average UV index in September
Walnut Grove, 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
Walnut Grove, CA
- Average cloud cover in September: 8
The months with the most cloud cover are March and December (Cloud cover 35).
The month with the least cloud cover is July (Cloud cover 4).
Average visibility in September
Walnut Grove, 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).
