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
Grafton's weather subtly changes with the onset of September, barely falling from a moderately hot 76.8°F (24.9°C) in August to a pleasant 71.4°F (21.9°C). The temperature dips to an average of 53.1°F (11.7°C) during September nights.Humidity
The average relative humidity in September is 78%.Rainfall
In Grafton, in September, during 11.8 rainfall days, 2.36" (60mm) of precipitation is typically accumulated. Throughout the year, there are 134.3 rainfall days, and 25.08" (637mm) of precipitation is accumulated.Snowfall
In Grafton, snow does not fall in June through September.Daylight
In September, the average length of the day is 12h and 29min.On the first day of September, sunrise is at 6:37 am and sunset at 7:46 pm. On the last day of the month, sunrise is at 7:09 am and sunset at 6:54 pm CDT.
Sunshine
In Grafton, Iowa, the average sunshine in September is 8.9h.UV index
In Grafton, the average daily maximum UV index in September is 4. A UV Index reading of 3 to 5 represents a moderate health risk from unprotected exposure to Sun's UV rays for the average person.Note: In September, an average UV index of 4 transforms into the following instructions:
Put precautions into practice - Protective measures against sun-induced damage are advised. Sun exposure should be minimized, especially during midday, to avoid harmful UV radiation. Protect your eyes, ears, face, and neck from the Sun by wearing a wide-brimmed hat.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What is the average September temperature in Grafton?
What is the average humidity in September?
How many days 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 long on average sun shines in September?
What is the UV index intensity in September?
Average temperature in September
Grafton, IA
- Average high temperature in September: 71.4°F
The warmest month (with the highest average high temperature) is July (79.2°F).
The month with the lowest average high temperature is January (21.6°F).
- Average low temperature in September: 53.1°F
The month with the highest average low temperature is July (62.6°F).
The coldest month (with the lowest average low temperature) is January (9°F).
Average pressure in September
Grafton, IA
- Average pressure in September: 30.01"Hg
The months with the highest atmospheric pressure are January and February (30.14"Hg).
The month with the lowest atmospheric pressure is June (29.88"Hg).
Average wind speed in September
Grafton, IA
- Average wind speed in September: 8.6mph
The windiest month (with the highest average wind speed) is April (10.8mph).
The calmest months (with the lowest average wind speed) are July and August (7.4mph).
Average humidity in September
Grafton, IA
- Average humidity in September: 78%
The month with the highest relative humidity is January (90%).
The months with the lowest relative humidity are April and October (72%).
Average rainfall in September
Grafton, IA
- Average rainfall in September: 2.36"
The wettest month (with the highest rainfall) is June (4.13").
The driest month (with the least rainfall) is January (0.94").
Average rainfall days in September
Grafton, IA
- Average rainfall days in September: 11.8 days
The month with the highest number of rainy days is June (18.4 days).
The month with the least rainy days is February (2.9 days).
Average snowfall in September
Grafton, IA
- Average snowfall in September: 0"
The month with the highest snowfall is February (5.94").
The months with the least snowfall are June, July, August and September (0").
Average snowfall days in September
Grafton, IA
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (13.8 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average daylight in September /
Average sunshine in September
Grafton, IA
- Average daylight in September: 12h and 3min
The month with the longest days is June (Average daylight: 15h and 18min).
The month with the shortest days is December (Average daylight: 9h and 0min).
- Average sunshine in September: 8h and 5min
The month with the most sunshine is July (Average sunshine: 9h and 48min).
The month with the least sunshine is January (Average sunshine: 3h and 24min).
Average sunshine days in September
Grafton, IA
- Average sunshine days in September: 15.1 days
The month with the most sunshine days is October (18.1 days).
The month with the least sunshine days is June (9.1 days).
Average UV index in September
Grafton, 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, November and December (UV index 1).
Average cloud cover in September
Grafton, IA
- Average cloud cover in September: 34
The month with the most cloud cover is January (Cloud cover 65).
The month with the least cloud cover is August (Cloud cover 32).
Average visibility in September
Grafton, IA
- Average visibility in September: 6mi
The months with the highest visibility are March, April, May, June, September, October and November (6mi).
The months with the lowest visibility are January, February, July, August and December (5mi).
Grafton, Iowa, USA
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