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
The average high-temperature slightly decreases in September, shifting from 94.6°F (34.8°C) in August to a still hot 88.9°F (31.6°C). Nighttime temperatures exhibit a substantial dip from daytime highs during September, averaging at a mild 59°F (15°C).Heat index
The heat index value for September is computed to be a hot 89.6°F (32°C). Long-standing exposure and activity could induce a feeling of tiredness and lead to heat cramps.Heat index data is primarily for areas with shade and subjected to light winds. The heat index may scale up by 15 Fahrenheit (8 Celsius) degrees with direct sun exposure.
Note: The heat index, also known as 'feels like' or 'apparent temperature', offers an insight into how hot it feels when we factor in moisture content. The impact of weather on an individual can be subjective, affected by the person's activity and heat perception, which can vary due to elements including wind, clothing, and metabolic differences. Direct sun rays have a notable impact on perceived temperature, which can raise the heat index by up to 15 Fahrenheit (8 Celsius) degrees. Heat index values remain especially vital for babies and toddlers. Kids often lack the knowledge about the necessity to take breaks and consume liquids. Thirst, as a late symptom of dehydration, necessitates the maintenance of hydration, particularly during enduring physical activities.
Humidity
The average relative humidity in September is 40%.Rainfall
In Rio Oso, in September, it is raining for 2.2 days, with typically 0.2" (5mm) of accumulated precipitation. Throughout the year, in Rio Oso, there are 78.2 rainfall days, and 20.43" (519mm) of precipitation is accumulated.Snowfall
January through November are months without snowfall.Daylight
In September, the average length of the day is 12h and 25min.On the first day of September, sunrise is at 6:35 am and sunset at 7:36 pm. On the last day of the month, sunrise is at 7:01 am and sunset at 6:49 pm PDT.
Sunshine
The average sunshine in September is 11.1h.UV index
In Rio Oso, California, the average daily maximum UV index in September is 5. A UV Index of 3 to 5 symbolizes a moderate threat to health from unsafe exposure to UV radiation for ordinary individuals.Note: The UV index of 5 in September translates into these instructions:
Undertake precautions - Obligation exists to protect against skin and eye damage. To prevent harmful UV exposure, minimize direct contact with the Sun around midday. Safeguard your eyes, ears, and face from sun rays with the aid of a wide-brim hat.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
How hot does it get in September?
What is the average humidity in September?
How many days does it rain in September?
When it does not snow?
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?
How high is the UV index in September?
Average temperature in September
Rio Oso, CA
- Average high temperature in September: 88.9°F
The warmest month (with the highest average high temperature) is July (95.4°F).
The month with the lowest average high temperature is December (54.3°F).
- Average low temperature in September: 59°F
The month with the highest average low temperature is July (61.3°F).
The coldest months (with the lowest average low temperature) are January and December (40.6°F).
Average pressure in September
Rio Oso, CA
- Average pressure in September: 29.92"Hg
The month with the highest atmospheric pressure is January (30.16"Hg).
The month with the lowest atmospheric pressure is June (29.9"Hg).
Average wind speed in September
Rio Oso, CA
- Average wind speed in September: 5mph
The windiest months (with the highest average wind speed) are March and May (6.2mph).
The calmest month (with the lowest average wind speed) is November (4.8mph).
Average humidity in September
Rio Oso, CA
- Average humidity in September: 40%
The month with the highest relative humidity is March (75%).
The month with the lowest relative humidity is July (39%).
Average rainfall in September
Rio Oso, CA
- Average rainfall in September: 0.2"
The wettest month (with the highest rainfall) is March (3.9").
The driest months (with the least rainfall) are July and August (0.04").
Average rainfall days in September
Rio Oso, CA
- Average rainfall days in September: 2.2 days
The month with the highest number of rainy days is March (14.3 days).
The month with the least rainy days is July (1 days).
Average snowfall days in September
Rio Oso, CA
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is December (0.1 days).
The months with the least snowfall days are January, February, March, April, May, June, July, August, September, October and November (0 days).
Average daylight in September /
Average sunshine in September
Rio Oso, CA
- Average daylight in September: 12h and 2min
The month with the longest days is June (Average daylight: 14h and 54min).
The month with the shortest days is December (Average daylight: 9h and 30min).
- Average sunshine in September: 11h and 1min
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 30min).
Average sunshine days in September
Rio Oso, CA
- Average sunshine days in September: 26.9 days
The month with the most sunshine days is July (30 days).
The month with the least sunshine days is March (16.1 days).
Average UV index in September
Rio Oso, CA
- Average UV index in September: 5
The months with the highest UV index are June and July (UV index 7).
The months with the lowest UV index are January, February, November and December (UV index 3).
Average cloud cover in September
Rio Oso, CA
- Average cloud cover in September: 9
The month with the most cloud cover is March (Cloud cover 41).
The month with the least cloud cover is July (Cloud cover 4).
Average visibility in September
Rio Oso, 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).
Rio Oso, California, USA
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