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
The shift from August to September includes a small decrease in the average high-temperature, from 81.1°F (27.3°C) to a still moderately hot 75.6°F (24.2°C). September witnesses an average low-temperature hovering around a moderate 55.9°F (13.3°C).Humidity
In Walnut, the average relative humidity in September is 74%.Rainfall
In September, the rain falls for 11.8 days. Throughout September, 2.28" (58mm) of precipitation is accumulated. In Walnut, during the entire year, the rain falls for 127.7 days and collects up to 26.57" (675mm) of precipitation.Snowfall
In Walnut, snow does not fall in June through September.Daylight
The average length of the day in September is 12h and 28min.On the first day of September, sunrise is at 6:47 am and sunset at 7:53 pm. On the last day of the month, sunrise is at 7:17 am and sunset at 7:03 pm CDT.
Sunshine
In September, the average sunshine is 9.1h.UV index
In Walnut, the average daily maximum UV index in September is 4. A UV Index estimate of 3 to 5 represents a medium vulnerability from exposure to the Sun's UV radiation for the average person.Note: The UV index of 4 in September translates into these instructions:
Exercise care. People with light skin might get burns in fewer than 30 minutes. Limiting sun exposure during midday hours helps in reducing the harmful effects of UV radiation. For optimum UV protection, wear sun-resistant attire complemented with a hat and quality shades.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What is the temperature in September?
What is the average humidity in September?
How much does it rain in September?
When it does not snow?
Does it snow in September?
What is the average length of the day in September?
When are sunrise and sunset in September?
How long on average sun shines in September?
How high is the UV index in September in Walnut?
Average temperature in September
Walnut, IA
- Average high temperature in September: 75.6°F
The warmest month (with the highest average high temperature) is July (82.9°F).
The month with the lowest average high temperature is January (28.8°F).
- Average low temperature in September: 55.9°F
The month with the highest average low temperature is July (65.1°F).
The coldest month (with the lowest average low temperature) is January (15.4°F).
Average pressure in September
Walnut, 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
Walnut, IA
- Average wind speed in September: 8.4mph
The windiest month (with the highest average wind speed) is April (10.7mph).
The calmest month (with the lowest average wind speed) is July (7mph).
Average humidity in September
Walnut, IA
- Average humidity in September: 74%
The month with the highest relative humidity is January (82%).
The month with the lowest relative humidity is October (68%).
Average rainfall in September
Walnut, IA
- Average rainfall in September: 2.28"
The wettest month (with the highest rainfall) is June (4.37").
The driest month (with the least rainfall) is January (0.87").
Average rainfall days in September
Walnut, IA
- Average rainfall days in September: 11.8 days
The month with the highest number of rainy days is May (17.1 days).
The month with the least rainy days is February (3.6 days).
Average snowfall in September
Walnut, IA
- Average snowfall in September: 0"
The month with the highest snowfall is February (3.7").
The months with the least snowfall are June, July, August and September (0").
Average snowfall days in September
Walnut, IA
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (9.8 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average daylight in September /
Average sunshine in September
Walnut, IA
- Average daylight in September: 12h and 3min
The month with the longest days is June (Average daylight: 15h and 6min).
The month with the shortest days is December (Average daylight: 9h and 12min).
- Average sunshine in September: 9h and 1min
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 36min).
Average sunshine days in September
Walnut, IA
- Average sunshine days in September: 16.3 days
The month with the most sunshine days is November (20.5 days).
The month with the least sunshine days is June (11 days).
Average UV index in September
Walnut, IA
- Average UV index in September: 4
The months with the highest UV index are June, July and August (UV index 6).
The months with the lowest UV index are January, February, October, November and December (UV index 2).
Average cloud cover in September
Walnut, IA
- Average cloud cover in September: 29
The month with the most cloud cover is January (Cloud cover 51).
The month with the least cloud cover is July (Cloud cover 27).
Average visibility in September
Walnut, IA
- Average visibility in September: 6mi
The months with the highest visibility are February, March, April, May, June, July, August, September, October, November and December (6mi).
The month with the lowest visibility is January (5mi).
Walnut, Iowa, USA
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