September weather forecastHartwick, IA
September
Weather in September
The first month of the autumn, September, is still a warm month in Hartwick, Iowa, with an average temperature varying between 55.4°F (13°C) and 74.7°F (23.7°C).Temperature
In September, Hartwick notes an average high-temperature of a still moderately hot 74.7°F (23.7°C), hardly different from the preceding month. September brings an average low-temperature of 55.4°F (13°C) to Hartwick.Humidity
The average relative humidity in September in Hartwick, Iowa, is 77%.Rainfall
In Hartwick, Iowa, in September, during 11.9 rainfall days, 2.72" (69mm) of precipitation is typically accumulated. In Hartwick, during the entire year, the rain falls for 135.6 days and collects up to 27.48" (698mm) of precipitation.Snowfall
June through September are months without snowfall in Hartwick.Daylight
In September, the average length of the day is 12h and 28min.On the first day of the month, sunrise is at 6:36 am and sunset at 7:42 pm. On the last day of September, in Hartwick, sunrise is at 7:06 am and sunset at 6:52 pm CDT.
Sunshine
In Hartwick, the average sunshine in September is 9.3h.UV index
The average daily maximum UV index in September is 4. A UV Index of 3 to 5 symbolizes a moderate threat to health from exposure to the Sun's UV radiation for the average person.Note: The average daily UV index of 4 in September transforms into the following instructions:
Exercise prevention - Protecting skin and eyes from harm is required. Considering the strength of solar radiation at midday, one should avoid direct Sun exposure. A wide-brimmed hat provides unparalleled sun protection for sensitive areas like the eyes, ears, and neck.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Hartwick, IA
- Average high temperature in September: 74.7°F
The warmest month (with the highest average high temperature) is July (81.1°F).
The month with the lowest average high temperature is January (27°F).
- Average low temperature in September: 55.4°F
The month with the highest average low temperature is July (64.8°F).
The coldest month (with the lowest average low temperature) is January (13.6°F).
Average pressure in September
Hartwick, IA
- Average pressure in September: 30.02"Hg
The month with the highest atmospheric pressure is January (30.15"Hg).
The month with the lowest atmospheric pressure is June (29.89"Hg).
Average wind speed in September
Hartwick, IA
- Average wind speed in September: 8.1mph
The windiest months (with the highest average wind speed) are January and April (10.7mph).
The calmest month (with the lowest average wind speed) is August (7mph).
Average humidity in September
Hartwick, IA
- Average humidity in September: 77%
The months with the highest relative humidity are January, February and July (84%).
The month with the lowest relative humidity is October (72%).
Average rainfall in September
Hartwick, IA
- Average rainfall in September: 2.72"
The wettest month (with the highest rainfall) is May (4.21").
The driest month (with the least rainfall) is January (1.02").
Average rainfall days in September
Hartwick, IA
- Average rainfall days in September: 11.9 days
The month with the highest number of rainy days is May (17.3 days).
The month with the least rainy days is February (4.6 days).
Average snowfall in September
Hartwick, IA
- Average snowfall in September: 0"
The month with the highest snowfall is January (4.49").
The months with the least snowfall are June, July, August and September (0").
Average snowfall days in September
Hartwick, 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
Hartwick, IA
- Average daylight in September: 12h and 30min
The month with the longest days is June (Average daylight: 15h and 12min).
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 6min).
The month with the least sunshine is January (Average sunshine: 4h and 0min).
Average sunshine days in September
Hartwick, IA
- Average sunshine days in September: 16.5 days
The month with the most sunshine days is December (18.5 days).
The month with the least sunshine days is June (10.8 days).
Average UV index in September
Hartwick, IA
- Average UV index in September: 4
The months with the highest UV index are June and July (UV index 6).
The month with the lowest UV index is January (UV index 1).
Average cloud cover in September
Hartwick, IA
- Average cloud cover in September: 30
The month with the most cloud cover is January (Cloud cover 56).
The months with the least cloud cover are August and September (Cloud cover 30).
Average visibility in September
Hartwick, IA
- Average visibility in September: 6mi
The months with the highest visibility are February, March, April, May, June, September, October, November and December (6mi).
The months with the lowest visibility are January, July and August (5mi).





