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 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
As August transitions into September, Royal sees a gentle drop in the average high-temperature, transitioning from a warm 78.3°F (25.7°C) to an agreeable 72.9°F (22.7°C). In the month of September, Royal's average low-temperature falls to a cool 53.8°F (12.1°C).Humidity
In September, the average relative humidity 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
In Royal, snow does not fall in June through September.Daylight
The average length of the day in September in Royal is 12h and 29min.On the first day of September in Royal, sunrise is at 6:46 am and sunset at 7:55 pm. On the last day of the month, sunrise is at 7:18 am and sunset at 7:03 pm CDT.
Sunshine
In Royal, the average sunshine in September is 9h.UV index
In September, the average daily maximum UV index is 4. A UV Index reading of 3 to 5 represents a moderate threat to health from exposure to the Sun's UV rays for ordinary individuals.Note: In September, a daily maximum UV index of 4 leads to the following instructions:
Adopt protective measures - It is advised to guard against sun damage. Avoiding the Sun during its peak radiation time around midday is a healthy practice. Always opt for UVA and UVB-resistant sunglasses on radiant days.
Frequently asked questions
What are the temperatures in Royal in September?
What is the average humidity in September in Royal?
How many days does it rain in September in Royal?
When it does not snow in Royal?
Does it snow in Royal in September?
How many hours of daylight does Royal have in September?
When are sunrise and sunset in September in Royal?
How long on average sun shines in September in Royal?
What is the UV index intensity in September in Royal?
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 3min
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).
Royal, Iowa, USA
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