September weather forecastNorwalk, IA
September
Weather in September
The first month of the autumn, September, is still a warm month in Norwalk, Iowa, with temperature in the range of an average low of 55.9°F (13.3°C) and an average high of 75.6°F (24.2°C).Temperature
The average high-temperature slightly decreases in September, shifting from 81.7°F (27.6°C) in August to a still warm 75.6°F (24.2°C). In the month of September, an average of 55.9°F (13.3°C) marks the low-temperature.Humidity
In Norwalk, the average relative humidity in September is 76%.Rainfall
In Norwalk, during September, the rain falls for 10.5 days and regularly aggregates up to 1.73" (44mm) of precipitation. In Norwalk, Iowa, during the entire year, the rain falls for 114.4 days and collects up to 16.38" (416mm) of precipitation.Snowfall
In Norwalk, snow does not fall in June through September.Daylight
In September, the average length of the day is 12h and 28min.On the first day of the month, sunrise is at 6:41 am and sunset at 7:47 pm. On the last day of September, sunrise is at 7:11 am and sunset at 6:57 pm CDT.
Sunshine
In Norwalk, Iowa, the average sunshine in September is 9.3h.UV index
In Norwalk, 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 radiation for average individuals.Note: An average maximum UV index of 4 in September leads to these recommendations:
Exercise caution. The susceptibility of light skin individuals to burns is less than 30 minutes. Being in direct Sun during midday can be harmful due to intense solar radiation; take precautions. Counter UV radiation's ill effects with clothing designed for sun safety and UV-resistant eyewear.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Norwalk, IA
- Average high temperature in September: 75.6°F
The warmest month (with the highest average high temperature) is July (83.1°F).
The month with the lowest average high temperature is January (28.2°F).
- Average low temperature in September: 55.9°F
The month with the highest average low temperature is July (65.5°F).
The coldest month (with the lowest average low temperature) is January (15.1°F).
Average pressure in September
Norwalk, IA
- Average pressure in September: 30.01"Hg
The month with the highest atmospheric pressure is January (30.16"Hg).
The month with the lowest atmospheric pressure is June (29.88"Hg).
Average wind speed in September
Norwalk, IA
- Average wind speed in September: 8mph
The windiest months (with the highest average wind speed) are January, February, March and April (10.3mph).
The calmest months (with the lowest average wind speed) are July and August (7mph).
Average humidity in September
Norwalk, IA
- Average humidity in September: 76%
The months with the highest relative humidity are January and June (82%).
The month with the lowest relative humidity is October (70%).
Average rainfall in September
Norwalk, IA
- Average rainfall in September: 1.73"
The wettest month (with the highest rainfall) is May (2.76").
The driest month (with the least rainfall) is January (0.47").
Average rainfall days in September
Norwalk, IA
- Average rainfall days in September: 10.5 days
The month with the highest number of rainy days is June (15.9 days).
The month with the least rainy days is February (3 days).
Average snowfall in September
Norwalk, IA
- Average snowfall in September: 0"
The month with the highest snowfall is January (2.24").
The months with the least snowfall are June, July, August and September (0").
Average snowfall days in September
Norwalk, IA
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (8.7 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average daylight in September /
Average sunshine in September
Norwalk, IA
- Average daylight in September: 12h and 30min
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 18min
The month with the most sunshine is July (Average sunshine: 10h and 18min).
The month with the least sunshine is January (Average sunshine: 4h and 18min).
Average sunshine days in September
Norwalk, IA
- Average sunshine days in September: 17.5 days
The month with the most sunshine days is December (22.3 days).
The month with the least sunshine days is June (12.2 days).
Average UV index in September
Norwalk, IA
- Average UV index in September: 4
The months with the highest UV index are June, July and August (UV index 6).
The month with the lowest UV index is January (UV index 1).
Average cloud cover in September
Norwalk, IA
- Average cloud cover in September: 29
The month with the most cloud cover is January (Cloud cover 54).
The months with the least cloud cover are July and September (Cloud cover 29).
Average visibility in September
Norwalk, 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).
