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
With the arrival of September, Grand River experiences a modest decline in average high-temperatures, transitioning from a moderately hot 81.9°F (27.7°C) in August to a still warm 76.1°F (24.5°C). During September, Grand River consistently records a temperature low averaging a mild 56.3°F (13.5°C).Humidity
In September, the average relative humidity in Grand River, Iowa, is 77%.Rainfall
In Grand River, in September, it is raining for 11.5 days, with typically 2.24" (57mm) of accumulated precipitation. Throughout the year, in Grand River, there are 132.4 rainfall days, and 20.24" (514mm) of precipitation is accumulated.Snowfall
In Grand River, Iowa, snow does not fall in June through September.Daylight
In Grand River, Iowa, the average length of the day in September is 12h and 27min.On the first day of September in Grand River, sunrise is at 6:43 am and sunset at 7:47 pm. On the last day of the month, sunrise is at 7:12 am and sunset at 6:58 pm CDT.
Sunshine
In Grand River, the average sunshine in September is 9.4h.UV index
The average daily maximum UV index in September in Grand River is 4. A UV Index of 3 to 5 symbolizes a medium vulnerability from exposure to the Sun's UV rays for the ordinary person.Note: The maximum UV index of 4 during September translates into these guidelines:
Preventative actions are necessary - Recommendations to ward off sunburn are given. Midday Sun has the strongest UV rays, making it crucial to limit exposure and find shade. It's wise to wear UVA and UVB-blocking sunglasses when the sun shines brightly.
Frequently asked questions
What is the temperature in September in Grand River?
What is the average humidity in September in Grand River?
How many days does it rain in September in Grand River?
When it does not snow in Grand River?
Does it snow in Grand River in September?
How many hours of daylight does Grand River have in September?
What time are sunrise and sunset in September in Grand River?
How many hours of sunshine does Grand River have in September?
How high is the UV index in September in Grand River?
Average temperature in September
Grand River, IA
- Average high temperature in September: 76.1°F
The warmest month (with the highest average high temperature) is July (83.5°F).
The month with the lowest average high temperature is January (30.6°F).
- Average low temperature in September: 56.3°F
The month with the highest average low temperature is July (66°F).
The coldest month (with the lowest average low temperature) is January (16.9°F).
Average pressure in September
Grand River, 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 (29.89"Hg).
Average wind speed in September
Grand River, IA
- Average wind speed in September: 7.9mph
The windiest months (with the highest average wind speed) are January, February and March (10.4mph).
The calmest months (with the lowest average wind speed) are July and August (6.9mph).
Average humidity in September
Grand River, IA
- Average humidity in September: 77%
The month with the highest relative humidity is June (83%).
The month with the lowest relative humidity is October (72%).
Average rainfall in September
Grand River, IA
- Average rainfall in September: 2.24"
The wettest month (with the highest rainfall) is June (3.43").
The driest months (with the least rainfall) are January and December (0.67").
Average rainfall days in September
Grand River, IA
- Average rainfall days in September: 11.5 days
The month with the highest number of rainy days is June (17.3 days).
The month with the least rainy days is January (4.8 days).
Average snowfall in September
Grand River, IA
- Average snowfall in September: 0"
The month with the highest snowfall is January (2.72").
The months with the least snowfall are June, July, August and September (0").
Average snowfall days in September
Grand River, IA
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (8.6 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average daylight in September /
Average sunshine in September
Grand River, 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 18min).
- Average sunshine in September: 9h and 2min
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 24min).
Average sunshine days in September
Grand River, IA
- Average sunshine days in September: 16 days
The month with the most sunshine days is December (20.3 days).
The month with the least sunshine days is June (8.9 days).
Average UV index in September
Grand River, 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
Grand River, 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 28).
Average visibility in September
Grand River, 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).
Grand River, Iowa, USA
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