September weather forecastStillwater, OK
September
Weather in September
In September, the oppressive heat of summer in Stillwater begins to lessen, marking the onset of autumn. The change in season is also marked by shorter days. Relative to August, the conditions in September are a bit cooler and less humid, but the weather remains largely warm. The average maximum temperature decreases to 84.4°F (29.1°C), as the heat of the summer begins to fade.Temperature
The beginning of September brings a minor change in the average high-temperature, shifting from a tropical 92.3°F (33.5°C) in August to a warm 84.4°F (29.1°C). Throughout the month of September, Stillwater expects an average low of 64.4°F (18°C).Heat index
The heat index for September is appraised at a hot 89.6°F (32°C). If one continues to be active during exposure, it might cause tiredness and subsequent heat cramps.Consider that heat index readings are for situations in the shade and light wind. The heat index could see an increase by 15 Fahrenheit (8 Celsius) degrees under direct sunshine.
Note: The heat index, also known as 'apparent temperature' or 'feels like', is a calculation that merges air temperature and relative humidity to depict the sensation of warmth. The influence of weather is personal, with a diverse population experiencing it differently due to differences in body mass, stature, and degree of activity. It is noteworthy to mention that direct sunlight exposure can augment the felt temperature, leading to an increase in the heat index by 15 Fahrenheit (8 Celsius) degrees. Heat index values are essentially critical for children. 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 67%.Rainfall
In Stillwater, Oklahoma, in September, during 12 rainfall days, 2.91" (74mm) of precipitation is typically accumulated. In Stillwater, during the entire year, the rain falls for 121.4 days and collects up to 25.28" (642mm) of precipitation.Snowfall
April through October are months without snowfall.Daylight
In September, the average length of the day is 12h and 23min.On the first day of the month, sunrise is at 7:00 am and sunset at 7:55 pm. On the last day of September, sunrise is at 7:23 am and sunset at 7:12 pm CDT.
Sunshine
The average sunshine in September is 8.6h.UV index
In September, the average daily maximum UV index is 5. A UV Index value of 3 to 5 symbolizes a moderate health risk from exposure to the Sun's UV radiation for ordinary individuals.Note: The maximum daily UV index of 5 in September converts into the following recommendations:
Make use of precautions - Shielding skin and eyes from injury is a requirement. The Sun's most intense and consequently most harmful UV radiation during midday hours should be decreased by minimizing exposure and seeking shade. By wearing a generously brimmed hat, you can cut UV radiation exposure significantly.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Stillwater, OK
- Average high temperature in September: 84.4°F
The warmest month (with the highest average high temperature) is July (93°F).
The month with the lowest average high temperature is January (47.5°F).
- Average low temperature in September: 64.4°F
The month with the highest average low temperature is July (73°F).
The coldest month (with the lowest average low temperature) is January (30.6°F).
Average pressure in September
Stillwater, OK
- Average pressure in September: 29.98"Hg
The month with the highest atmospheric pressure is January (30.16"Hg).
The month with the lowest atmospheric pressure is June (29.87"Hg).
Average wind speed in September
Stillwater, OK
- Average wind speed in September: 8.5mph
The windiest month (with the highest average wind speed) is April (11.5mph).
The calmest month (with the lowest average wind speed) is August (8.2mph).
Average humidity in September
Stillwater, OK
- Average humidity in September: 67%
The month with the highest relative humidity is May (75%).
The month with the lowest relative humidity is August (62%).
Average rainfall in September
Stillwater, OK
- Average rainfall in September: 2.91"
The wettest month (with the highest rainfall) is May (4.25").
The driest month (with the least rainfall) is December (0.98").
Average rainfall days in September
Stillwater, OK
- Average rainfall days in September: 12 days
The month with the highest number of rainy days is May (14.6 days).
The month with the least rainy days is January (4.8 days).
Average snowfall in September
Stillwater, OK
- Average snowfall in September: 0"
The month with the highest snowfall is February (1.42").
The months with the least snowfall are April, May, June, July, August, September and October (0").
Average snowfall days in September
Stillwater, OK
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is February (2.8 days).
The months with the least snowfall days are May, June, July, August, September and October (0 days).
Average daylight in September /
Average sunshine in September
Stillwater, OK
- Average daylight in September: 12h and 24min
The month with the longest days is June (Average daylight: 14h and 36min).
The month with the shortest days is December (Average daylight: 9h and 48min).
- Average sunshine in September: 8h and 36min
The month with the most sunshine is August (Average sunshine: 11h and 12min).
The month with the least sunshine is December (Average sunshine: 6h and 6min).
Average sunshine days in September
Stillwater, OK
- Average sunshine days in September: 15.8 days
The month with the most sunshine days is January (22.9 days).
The month with the least sunshine days is May (13.7 days).
Average UV index in September
Stillwater, OK
- Average UV index in September: 5
The months with the highest UV index are June, July and August (UV index 7).
The month with the lowest UV index is December (UV index 2).
Average cloud cover in September
Stillwater, OK
- Average cloud cover in September: 26
The month with the most cloud cover is March (Cloud cover 37).
The month with the least cloud cover is August (Cloud cover 19).
Average visibility in September
Stillwater, OK
- 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).
