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 advent of September, Rochester's high-temperatures adjust to a still warm 77.4°F (25.2°C), closely aligning with the preceding month. Throughout September, an average low-temperature of 58.6°F (14.8°C) is experienced in Rochester.Humidity
In Rochester, the average relative humidity in September is 75%.Rainfall
In Rochester, Illinois, in September, it is raining for 12 days, with typically 1.89" (48mm) of accumulated precipitation. Throughout the year, in Rochester, there are 141.7 rainfall days, and 22.72" (577mm) of precipitation is accumulated.Snowfall
May through October are months without snowfall.Daylight
The average length of the day in September is 12h and 26min.On the first day of September, sunrise is at 6:26 am and sunset at 7:28 pm. On the last day of the month, sunrise is at 6:54 am and sunset at 6:41 pm CDT.
Sunshine
The average sunshine in September is 9.3h.UV index
In September, the average daily maximum UV index in Rochester is 5. A UV Index of 3 to 5 symbolizes a medium vulnerability from unprotected exposure to Sun's UV rays for the ordinary person.Note: In September, the maximum UV index of 5 translates into these guidelines:
Exercise prevention - Warding off sunburn is urged. Sun's radiation is most powerful around mid-day, so it's best to limit outdoor activities during this time. Employ a wide-brim hat for potent defense against up to 50% of UV rays.
Frequently asked questions
What are September temperatures in Rochester?
What is the average humidity in September in Rochester?
How many days does it rain in September in Rochester?
When it does not snow in Rochester?
What is the average length of the day in September in Rochester?
What time are sunrise and sunset in September in Rochester?
How many hours of sunshine does Rochester have in September?
What is the UV index intensity in September in Rochester?
Average temperature in September
Rochester, IL
- Average high temperature in September: 77.4°F
The warmest month (with the highest average high temperature) is July (82.8°F).
The month with the lowest average high temperature is January (33.4°F).
- Average low temperature in September: 58.6°F
The month with the highest average low temperature is July (66°F).
The coldest month (with the lowest average low temperature) is January (21.4°F).
Average pressure in September
Rochester, IL
- Average pressure in September: 30.03"Hg
The month with the highest atmospheric pressure is January (30.15"Hg).
The month with the lowest atmospheric pressure is June (29.92"Hg).
Average wind speed in September
Rochester, IL
- Average wind speed in September: 7mph
The windiest month (with the highest average wind speed) is January (10.4mph).
The calmest months (with the lowest average wind speed) are July and August (6.2mph).
Average humidity in September
Rochester, IL
- Average humidity in September: 75%
The month with the highest relative humidity is July (84%).
The month with the lowest relative humidity is October (70%).
Average rainfall in September
Rochester, IL
- Average rainfall in September: 1.89"
The wettest month (with the highest rainfall) is April (2.64").
The driest month (with the least rainfall) is December (1.14").
Average rainfall days in September
Rochester, IL
- Average rainfall days in September: 12 days
The month with the highest number of rainy days is May (17.7 days).
The month with the least rainy days is February (6.2 days).
Average snowfall in September
Rochester, IL
- Average snowfall in September: 0"
The month with the highest snowfall is February (1.85").
The months with the least snowfall are May, June, July, August, September and October (0").
Average snowfall days in September
Rochester, IL
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (8.3 days).
The months with the least snowfall days are May, June, July, August and September (0 days).
Average daylight in September /
Average sunshine in September
Rochester, IL
- Average daylight in September: 12h and 2min
The month with the longest days is June (Average daylight: 14h and 54min).
The month with the shortest days is December (Average daylight: 9h and 24min).
- Average sunshine in September: 9h and 2min
The month with the most sunshine is June (Average sunshine: 10h and 24min).
The month with the least sunshine is January (Average sunshine: 4h and 12min).
Average sunshine days in September
Rochester, IL
- Average sunshine days in September: 15.7 days
The month with the most sunshine days is October (18.7 days).
The month with the least sunshine days is July (11 days).
Average UV index in September
Rochester, IL
- Average UV index in September: 5
The months with the highest UV index are June, July and August (UV index 6).
The months with the lowest UV index are January, February, November and December (UV index 2).
Average cloud cover in September
Rochester, IL
- Average cloud cover in September: 30
The month with the most cloud cover is January (Cloud cover 55).
The month with the least cloud cover is June (Cloud cover 29).
Average visibility in September
Rochester, IL
- Average visibility in September: 6mi
The months with the highest visibility are January, February, March, April, May, June, September, October, November and December (6mi).
The months with the lowest visibility are July and August (5mi).
Rochester, Illinois, USA
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