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
September is marked by a subtle drop in average high-temperatures, transitioning from 81.1°F (27.3°C) in August to a still warm 75.2°F (24°C). Harper experiences an average low-temperature of 56.3°F (13.5°C) in the month of September.Humidity
The average relative humidity in September is 76%.Rainfall
In Harper, during September, the rain falls for 12.1 days and regularly aggregates up to 2.76" (70mm) of precipitation. In Harper, during the entire year, the rain falls for 137.9 days and collects up to 27.76" (705mm) of precipitation.Snowfall
June through September are months without snowfall.Daylight
In September, the average length of the day is 12h and 28min.On the first day of the month, sunrise is at 6:35 am and sunset at 7:40 pm. On the last day of September, sunrise is at 7:04 am and sunset at 6:51 pm CDT.
Sunshine
The average sunshine in September is 9.4h.UV index
In Harper, the average daily maximum UV index in September is 4. A UV Index reading of 3 to 5 represents a moderate threat to health from unprotected exposure to Sun's UV rays for the average person.Note: The maximum UV index of 4 during September leads to these instructions:
Guard yourself - An obligation to protect skin and eyes from harm exists. Avoid the Sun's strongest UV rays by seeking shade and limiting exposure during midday. Sunglasses that guard against UVA and UVB rays are pivotal in minimizing sun-induced ocular damage.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What is the usual temperature for Harper 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?
What time are sunrise and sunset in September?
How many hours of sunshine does Harper have in September?
What is the UV index intensity in September?
Average temperature in September
Harper, IA
- Average high temperature in September: 75.2°F
The warmest month (with the highest average high temperature) is July (82°F).
The month with the lowest average high temperature is January (28.6°F).
- Average low temperature in September: 56.3°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 (15.6°F).
Average pressure in September
Harper, 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
Harper, IA
- Average wind speed in September: 8mph
The windiest month (with the highest average wind speed) is January (10.7mph).
The calmest month (with the lowest average wind speed) is August (6.9mph).
Average humidity in September
Harper, IA
- Average humidity in September: 76%
The month with the highest relative humidity is July (83%).
The month with the lowest relative humidity is October (72%).
Average rainfall in September
Harper, IA
- Average rainfall in September: 2.76"
The wettest month (with the highest rainfall) is May (4.17").
The driest month (with the least rainfall) is February (0.98").
Average rainfall days in September
Harper, IA
- Average rainfall days in September: 12.1 days
The month with the highest number of rainy days is May (17.7 days).
The month with the least rainy days is February (4.9 days).
Average snowfall in September
Harper, IA
- Average snowfall in September: 0"
The month with the highest snowfall is January (4.06").
The months with the least snowfall are June, July, August and September (0").
Average snowfall days in September
Harper, IA
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (9.5 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average daylight in September /
Average sunshine in September
Harper, 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 2min
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 12min).
Average sunshine days in September
Harper, IA
- Average sunshine days in September: 15.9 days
The month with the most sunshine days is December (19.1 days).
The month with the least sunshine days is June (10.3 days).
Average UV index in September
Harper, 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, February, October, November and December (UV index 2).
Average cloud cover in September
Harper, IA
- Average cloud cover in September: 29
The month with the most cloud cover is January (Cloud cover 55).
The months with the least cloud cover are August and September (Cloud cover 29).
Average visibility in September
Harper, IA
- Average visibility in September: 6mi
The months with the highest visibility are January, February, March, April, May, June, August, September, October, November and December (6mi).
The month with the lowest visibility is July (5mi).
Harper, Iowa, USA
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