September weather forecastRoyal, IA
September
Weather in September
The first month of the autumn, September, is still a pleasant month in Royal, Iowa, with temperature in the range of an average high of 72.9°F (22.7°C) and an average low of 53.8°F (12.1°C).Temperature
September reveals a small adjustment in temperature, transitioning from an average high of a moderately hot 78.3°F (25.7°C) in August to an agreeable 72.9°F (22.7°C). In Royal, September nights witness a steady temperature drop to a fresh 53.8°F (12.1°C).Humidity
In Royal, the average relative humidity in September is 74%.Rainfall
In September, the rain falls for 10.5 days. Throughout September, 1.3" (33mm) of precipitation is accumulated. Throughout the year, there are 112.3 rainfall days, and 15.31" (389mm) of precipitation is accumulated.Snowfall
June through September are months without snowfall.Daylight
The average length of the day in September in Royal is 12h and 29min.On the first day of the month, sunrise is at 6:46 am and sunset at 7:55 pm. On the last day of September, sunrise is at 7:18 am and sunset at 7:03 pm CDT.
Sunshine
The average sunshine in September in Royal is 9h.UV index
In Royal, the average daily maximum UV index in September is 4. A UV Index of 3 to 5 symbolizes a medium vulnerability from exposure to the Sun's UV rays for average individuals.Note: In September, the maximum UV index of 4 transforms into these recommendations:
Undertake precautions - Obligation exists to protect against skin and eye damage. Avoid the Sun's strongest UV rays by seeking shade and limiting exposure during midday. 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
Royal, IA
- Average high temperature in September: 72.9°F
The warmest month (with the highest average high temperature) is July (80.2°F).
The month with the lowest average high temperature is January (22.8°F).
- Average low temperature in September: 53.8°F
The month with the highest average low temperature is July (63.1°F).
The coldest month (with the lowest average low temperature) is January (10.6°F).
Average pressure in September
Royal, IA
- Average pressure in September: 30"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
Royal, IA
- Average wind speed in September: 9mph
The windiest months (with the highest average wind speed) are January and April (11.1mph).
The calmest month (with the lowest average wind speed) is July (7.6mph).
Average humidity in September
Royal, IA
- Average humidity in September: 74%
The month with the highest relative humidity is January (87%).
The month with the lowest relative humidity is October (68%).
Average rainfall in September
Royal, IA
- Average rainfall in September: 1.3"
The wettest month (with the highest rainfall) is June (2.44").
The driest month (with the least rainfall) is January (0.43").
Average rainfall days in September
Royal, IA
- Average rainfall days in September: 10.5 days
The month with the highest number of rainy days is May (15.5 days).
The month with the least rainy days is February (2.7 days).
Average snowfall in September
Royal, IA
- Average snowfall in September: 0"
The month with the highest snowfall is February (2.72").
The months with the least snowfall are June, July, August and September (0").
Average snowfall days in September
Royal, IA
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (10.8 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average daylight in September /
Average sunshine in September
Royal, IA
- Average daylight in September: 12h and 30min
The month with the longest days is June (Average daylight: 15h and 18min).
The month with the shortest days is December (Average daylight: 9h and 6min).
- Average sunshine in September: 9h and 0min
The month with the most sunshine is July (Average sunshine: 10h and 24min).
The month with the least sunshine is January (Average sunshine: 4h and 0min).
Average sunshine days in September
Royal, IA
- Average sunshine days in September: 17.5 days
The month with the most sunshine days is November (20.1 days).
The month with the least sunshine days is June (10.8 days).
Average UV index in September
Royal, IA
- Average UV index in September: 4
The months with the highest UV index are June and July (UV index 6).
The months with the lowest UV index are January and February (UV index 1).
Average cloud cover in September
Royal, IA
- Average cloud cover in September: 31
The month with the most cloud cover is January (Cloud cover 58).
The month with the least cloud cover is July (Cloud cover 30).
Average visibility in September
Royal, IA
- 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).
