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 snowfall 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
Riverside's September showcases an average high-temperature of a still tropical 88.3°F (31.3°C), hardly distinct from August's 91.2°F (32.9°C). Marked by a significant temperature drop from daytime highs, the average nighttime temperature in Riverside lowers to an enjoyable 64°F (17.8°C) throughout September.Heat index
The average heat index in September is appraised at a tropical 89.6°F (32°C). Long-standing exposure and activity could induce a feeling of tiredness and lead to heat cramps.The standards for the heat index are set for locations in shade and under light breezes. Exposure to unobstructed sunshine could lead to an increase in the heat index by 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'feels like' or 'felt air temperature', is a calculation that merges air temperature and relative humidity to depict the sensation of warmth. Factors encompassing physical activity, clothing, and metabolic differences have a role in shaping the individual's impression of temperature. It is important to note that direct sunlight can intensify the weather impact, potentially raising the heat index by 15 Fahrenheit (8 Celsius) degrees. Heat index values hold great significance to children. Children commonly overlook the importance of rest and fluid replenishment. Thirst, being a delayed sign of dehydration, emphasizes the need to keep hydration up, especially during lengthy physical activities.
Humidity
In Riverside, California, the average relative humidity in September is 45%.Rainfall
In September, the rain falls for 2.1 days. Throughout September, 0.08" (2mm) of precipitation is accumulated. Throughout the year, in Riverside, there are 49 rainfall days, and 7.32" (186mm) of precipitation is accumulated.Snowfall
In Riverside, snow does not fall in January, March through December.Daylight
In Riverside, California, the average length of the day in September is 12h and 22min.On the first day of the month, sunrise is at 6:23 am and sunset at 7:14 pm. On the last day of September, in Riverside, sunrise is at 6:43 am and sunset at 6:34 pm PDT.
Sunshine
In September, the average sunshine in Riverside is 10.6h.UV index
In Riverside, the average daily maximum UV index in September is 6. A UV Index estimate of 6 to 7 represents a high health hazard from unsafe exposure to UV radiation for ordinary individuals.Note: In September, the average maximum UV index of 6 translates into the following recommendations:
Skirt overexposure. People with light complexions might get scorched in under 20 minutes. Stay in the shade and limit direct sun exposure between 10 a.m. and 4 p.m., when UV radiation is at its strongest. Remember, however, that not all shade structures provide full sun protection. Enhance your sun protection with tightly woven, yet airy clothing.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
How hot does it get in Riverside in September?
What is the average humidity in September in Riverside?
How many days does it rain in September in Riverside?
When it does not snow in Riverside?
What is the average length of the day in September in Riverside?
When is the sunrise / sunset in September in Riverside?
How many hours of sunshine does Riverside have in September?
How high is the UV index in September in Riverside?
Average temperature in September
Riverside, CA
- Average high temperature in September: 88.3°F
The warmest month (with the highest average high temperature) is August (91.2°F).
The month with the lowest average high temperature is December (63.3°F).
- Average low temperature in September: 64°F
The month with the highest average low temperature is August (66.4°F).
The coldest month (with the lowest average low temperature) is December (45.9°F).
Average pressure in September
Riverside, CA
- Average pressure in September: 29.88"Hg
The month with the highest atmospheric pressure is January (30.1"Hg).
The month with the lowest atmospheric pressure is June (29.86"Hg).
Average wind speed in September
Riverside, CA
- Average wind speed in September: 4.4mph
The windiest month (with the highest average wind speed) is May (5.6mph).
The calmest month (with the lowest average wind speed) is September (4.4mph).
Average humidity in September
Riverside, CA
- Average humidity in September: 45%
The month with the highest relative humidity is May (56%).
The month with the lowest relative humidity is August (43%).
Average rainfall in September
Riverside, CA
- Average rainfall in September: 0.08"
The wettest months (with the highest rainfall) are February and December (1.61").
The driest month (with the least rainfall) is June (0.04").
Average rainfall days in September
Riverside, CA
- Average rainfall days in September: 2.1 days
The month with the highest number of rainy days is March (7.7 days).
The month with the least rainy days is June (1.1 days).
Average snowfall days in September
Riverside, CA
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is February (0.1 days).
The months with the least snowfall days are January, March, April, May, June, July, August, September, October, November and December (0 days).
Average daylight in September /
Average sunshine in September
Riverside, CA
- Average daylight in September: 12h and 2min
The month with the longest days is June (Average daylight: 14h and 24min).
The month with the shortest days is December (Average daylight: 9h and 54min).
- Average sunshine in September: 10h and 4min
The months with the most sunshine are July and August (Average sunshine: 12h and 6min).
The months with the least sunshine are February and December (Average sunshine: 6h and 48min).
Average sunshine days in September
Riverside, CA
- Average sunshine days in September: 25.8 days
The month with the most sunshine days is June (27.9 days).
The month with the least sunshine days is February (21.6 days).
Average UV index in September
Riverside, CA
- Average UV index in September: 6
The months with the highest UV index are July and August (UV index 7).
The month with the lowest UV index is December (UV index 3).
Average cloud cover in September
Riverside, CA
- Average cloud cover in September: 7
The months with the most cloud cover are February and March (Cloud cover 23).
The month with the least cloud cover is August (Cloud cover 5).
Average visibility in September
Riverside, 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).
Riverside, California, USA
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