September weather forecast
Olmsted, IL

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Weather in September

The first month of the autumn, September, is also a moderately hot month in Olmsted, Illinois, with temperature in the range of an average low of 61.9°F (16.6°C) and an average high of 81.5°F (27.5°C).

Temperature

With the arrival of September, Olmsted's average high-temperature registers at a moderately hot 81.5°F (27.5°C), indicating a subtle variation from the previous month. Olmsted records a steady low-temperature average of 61.9°F (16.6°C) during September.

Heat index

The heat index value during September is appraised at a hot 86°F (30°C). If one stays active during extended exposure, it might induce fatigue and result in heat cramps.
One should consider that heat index numbers are for shaded settings and light wind. An exposure to direct sunlight may lift the heat index values by 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'apparent temperature' or 'real feel', marries air temperature and humidity to produce a value illustrating perceived warmth. The effect of weather is individual, with a variety of people experiencing it differently due to distinctions in body mass, height, and level of activity. Always consider that direct sunlight exposure might heighten the heat's effects, pushing the heat index up by 15 Fahrenheit (8 Celsius) degrees. Heat index values are highly critical for babies and toddlers. Youngsters frequently overlook the need for breaks and fluid intake. Thirst is an advanced sign of dehydration - thereby highlighting the importance of keeping hydrated, particularly during long physical activities.

Humidity

In September, the average relative humidity is 72%.

Rainfall

September is the month with the least rainfall. Rain falls for 11.4 days and accumulates 1.42" (36mm) of precipitation.

Snowfall

May through September are months without snowfall.

Daylight

In September, the average length of the day is 12h and 25min.
On the first day of the month, sunrise is at 6:27 am and sunset at 7:24 pm. On the last day of September, sunrise is at 6:51 am and sunset at 6:40 pm CDT.

Sunshine

In Olmsted, the average sunshine in September is 9.6h.

UV index

The average daily maximum UV index in September is 5. A UV Index reading of 3 to 5 represents a moderate threat to health from exposure to the Sun's UV radiation for the ordinary person.
Note: The UV index of 5 during September leads to these advisories:
Exercise prevention - Warding off sunburn is urged. Solar radiation is at its peak intensity during midday, so it's advisable to stay indoors or in the shade. A wide-brimmed hat is a staple for defending the face, eyes, ears, and neck from the Sun.
Updated: Aug 11, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What are September temperatures in Olmsted?

The high-temperature, in September, in Olmsted, records 81.5°F (27.5°C), while the low-temperature is 61.9°F (16.6°C). In September, the average heat index (a.k.a. 'feels like', 'apparent temperature'), which factors the actual air temperature with the relative humidity, is appraised at 86°F (30°C).

What is the average humidity in September?

The average relative humidity in September is 72%.

What is the driest month?

September is the month with the least rainfall. Rain falls for 11.4 days and accumulates 1.42" (36mm) of precipitation.

How many days does it rain in September?

In Olmsted, in September, it is raining for 11.4 days, with typically 1.42" (36mm) of accumulated precipitation.

When it does not snow?

May through September are months without snowfall.

Does it snow in September?

In Olmsted, in September, it doesn't snow. In October, it regularly snows.

What is the average length of the day in September?

In Olmsted, the average day length in September is 12h and 25min.

What time are sunrise and sunset in September?

On the first day of September, sunrise is at 6:27 am and sunset at 7:24 pm. On the last day of the month, sunrise is at 6:51 am and sunset at 6:40 pm CDT.

How many hours of sunshine does Olmsted have in September?

In September, the average sunshine duration is 9.6h.

How high is the UV index in September?

The average daily maximum UV index in September is 5. A UV Index estimate of 3 to 5 represents a medium hazard to health from exposure to Sun's UV rays.
Average humidity
Average rainfall days
Average snowfall
Average snowfall days
Average daylight
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in September
Olmsted, IL

Average temperature in September - Olmsted, IL
  • Average high temperature in September: 81.5°F

The warmest month (with the highest average high temperature) is July (88.2°F).
The month with the lowest average high temperature is January (41.2°F).

  • Average low temperature in September: 61.9°F

The month with the highest average low temperature is July (69.8°F).
The coldest month (with the lowest average low temperature) is January (28.4°F).

Average pressure in September
Olmsted, IL

Average pressure in September - Olmsted, IL
  • Average pressure in September: 30.02"Hg

The month with the highest atmospheric pressure is January (30.16"Hg).
The month with the lowest atmospheric pressure is June (29.94"Hg).

Average wind speed in September
Olmsted, IL

Average wind speed in September - Olmsted, IL
  • Average wind speed in September: 6.3mph

The windiest months (with the highest average wind speed) are January, February and March (9.1mph).
The calmest months (with the lowest average wind speed) are July and August (5.7mph).

Average humidity in September
Olmsted, IL

Average humidity in September - Olmsted, IL
  • Average humidity in September: 72%

The months with the highest relative humidity are February, March, May and December (78%).
The month with the lowest relative humidity is October (69%).

Average rainfall in September
Olmsted, IL

Average rainfall in September - Olmsted, IL
  • Average rainfall in September: 1.42"

The wettest month (with the highest rainfall) is April (4.21").
The driest month (with the least rainfall) is September (1.42").

Average rainfall days in September
Olmsted, IL

Average rainfall days in September - Olmsted, IL
  • Average rainfall days in September: 11.4 days

The month with the highest number of rainy days is May (17.1 days).
The month with the least rainy days is January (9.8 days).

Average snowfall in September
Olmsted, IL

Average snowfall in September - Olmsted, IL
  • Average snowfall in September: 0"

The month with the highest snowfall is February (1.5").
The months with the least snowfall are May, June, July, August and September (0").

Average snowfall days in September
Olmsted, IL

Average snowfall days in September - Olmsted, IL
  • Average snowfall days in September: 0 days

The month with the highest number of snowfall days is February (3.8 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
Olmsted, IL

Average daylight in September / Average sunshine in September - Olmsted, IL
  • Average daylight in September: 12h and 2min

The month with the longest days is June (Average daylight: 14h and 42min).
The month with the shortest days is December (Average daylight: 9h and 42min).

  • Average sunshine in September: 9h and 4min

The month with the most sunshine is June (Average sunshine: 10h and 42min).
The month with the least sunshine is February (Average sunshine: 4h and 42min).

Average sunshine days in September
Olmsted, IL

Average sunshine days in September - Olmsted, IL
  • Average sunshine days in September: 16.5 days

The month with the most sunshine days is October (18.5 days).
The month with the least sunshine days is May (12.3 days).

Average UV index in September
Olmsted, IL

Average UV index in September - Olmsted, IL
  • Average UV index in September: 5

The months with the highest UV index are May, June, July and August (UV index 6).
The months with the lowest UV index are January, February and December (UV index 2).

Average cloud cover in September
Olmsted, IL

Average cloud cover in September - Olmsted, IL
  • Average cloud cover in September: 27

The month with the most cloud cover is February (Cloud cover 49).
The month with the least cloud cover is June (Cloud cover 26).

Average visibility in September
Olmsted, IL

Average visibility in September - Olmsted, IL
  • 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).

Olmsted, Illinois, USA

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