October weather forecast
Harrisburg, IL

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Weather in October

September’s chill extends into October in Harrisburg, Illinois, resulting in a further dip in temperatures, from 49.3°F (9.6°C) to 67.8°F (19.9°C). This month is an integral part of the Fall season, which brings along diverse hues of orange, gold, and red to the leafy landscape. As rain subsides, outdoor activities gain traction against the backdrop of vibrant foliage and crisp air. October ushers in the chill that signifies winter is not too far behind, especially noticeable during the final days.

Temperature

October in Harrisburg, Illinois, involves a decrease in temperature, down from a warm 80.8°F (27.1°C) in September to an enjoyable 67.8°F (19.9°C). Nighttime temperatures hover around an average low of 49.3°F (9.6°C) in October.

Humidity

The least humid month is October, with an average relative humidity of 70%.

Rainfall

In Harrisburg, Illinois, during October, the rain falls for 10.5 days and regularly aggregates up to 2.64" (67mm) of precipitation. Throughout the year, there are 158.6 rainfall days, and 36.02" (915mm) of precipitation is accumulated.

Snowfall

Months with snowfall are January through April, October through December. October is the first month it typically snows. Throughout October, in the average 0.1 snowfall days, it receives 0.08" (2mm) of snow. In Harrisburg, during the entire year, snow falls for 17.7 days and aggregates up to 6.57" (167mm) of snow.

Daylight

In October, the average length of the day is 11h and 13min.
On the first day of October, sunrise is at 6:50 am and sunset at 6:36 pm. On the last day of the month, sunrise is at 7:19 am and sunset at 5:56 pm CDT.

Sunshine

In Harrisburg, the average sunshine in October is 6.7h.

UV index

In Harrisburg, the average daily maximum UV index in October is 3. A UV Index estimate of 3 to 5 represents a medium health hazard from unsafe exposure to UV radiation for ordinary individuals.
Note: In October, the maximum UV index of 3 translates into these guidelines:
Exercise prudence. Persons with fair skin could be burned in under 30 minutes. The Sun's radiation is especially intense around midday; try to stay in shade during this period. Your best bet for sun defense on the face, eyes, and neck is a hat with a wide brim. Remember to consider! The UV radiation from the Sun can be intensified nearly twice by the reflection of snow.
Updated: Jul 21, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What is the average October temperature?

In Harrisburg, 67.8°F (19.9°C) is the average high-temperature and 49.3°F (9.6°C) is the average low-temperature during October. The average heat index (a.k.a. 'real feel', 'feels like'), which calculates the temperature value influenced by the moisture in the air, in September is evaluated at 84.2°F (29°C).

What is the least humid month?

The least humid month is October, with an average relative humidity of 70%.

What is the average humidity in October in Harrisburg?

In October, the average relative humidity is 70%.

How much does it rain in October?

In Harrisburg, in October, it is raining for 10.5 days, with typically 2.64" (67mm) of accumulated precipitation.

When does it start to snow?

October is the first month it typically snows. Throughout October, in the average 0.1 snowfall days, it receives 0.08" (2mm) of snow.

What is the average length of the day in October?

In Harrisburg, the average day length in October is 11h and 13min.

When is the sunrise / sunset in October?

On the first day of October, sunrise is at 6:50 am and sunset at 6:36 pm. On the last day of the month, sunrise is at 7:19 am and sunset at 5:56 pm CDT.

How many hours of sunshine does Harrisburg have in October?

In Harrisburg, the average sunshine duration in October is 6.7h.

What is the UV index intensity in October?

In October, the average daily maximum UV index is 3. A UV Index of 3 to 5 symbolizes a medium hazard to health from exposure to Sun's UV rays.
Average humidity
Average rainfall days
Average snowfall days
Average daylight
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in October
Harrisburg, IL

Average temperature in October - Harrisburg, IL
  • Average high temperature in October: 67.8°F

The warmest month (with the highest average high temperature) is July (87.3°F).
The month with the lowest average high temperature is January (39.7°F).

  • Average low temperature in October: 49.3°F

The month with the highest average low temperature is July (68.5°F).
The coldest month (with the lowest average low temperature) is January (26.2°F).

Average pressure in October
Harrisburg, IL

Average pressure in October - Harrisburg, IL
  • Average pressure in October: 30.04"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 October
Harrisburg, IL

Average wind speed in October - Harrisburg, IL
  • Average wind speed in October: 8mph

The windiest months (with the highest average wind speed) are January and February (9.4mph).
The calmest months (with the lowest average wind speed) are July and August (5.8mph).

Average humidity in October
Harrisburg, IL

Average humidity in October - Harrisburg, IL
  • Average humidity in October: 70%

The month with the highest relative humidity is May (79%).
The month with the lowest relative humidity is October (70%).

Average rainfall in October
Harrisburg, IL

Average rainfall in October - Harrisburg, IL
  • Average rainfall in October: 2.64"

The wettest month (with the highest rainfall) is April (4.8").
The driest month (with the least rainfall) is September (1.57").

Average rainfall days in October
Harrisburg, IL

Average rainfall days in October - Harrisburg, IL
  • Average rainfall days in October: 10.5 days

The month with the highest number of rainy days is May (18.5 days).
The month with the least rainy days is November (9.7 days).

Average snowfall in October
Harrisburg, IL

Average snowfall in October - Harrisburg, IL
  • Average snowfall in October: 0.08"

The month with the highest snowfall is January (1.73").
The months with the least snowfall are May, June, July, August and September (0").

Average snowfall days in October
Harrisburg, IL

Average snowfall days in October - Harrisburg, IL
  • Average snowfall days in October: 0.1 days

The month with the highest number of snowfall days is January (5.3 days).
The months with the least snowfall days are May, June, July, August and September (0 days).

Average daylight in October /
Average sunshine in October
Harrisburg, IL

Average daylight in October / Average sunshine in October - Harrisburg, IL
  • Average daylight in October: 11h and 1min

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 36min).

  • Average sunshine in October: 6h and 4min

The month with the most sunshine is June (Average sunshine: 10h and 36min).
The month with the least sunshine is January (Average sunshine: 4h and 36min).

Average sunshine days in October
Harrisburg, IL

Average sunshine days in October - Harrisburg, IL
  • Average sunshine days in October: 19.5 days

The month with the most sunshine days is October (19.5 days).
The month with the least sunshine days is May (9.9 days).

Average UV index in October
Harrisburg, IL

Average UV index in October - Harrisburg, IL
  • Average UV index in October: 3

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 October
Harrisburg, IL

Average cloud cover in October - Harrisburg, IL
  • Average cloud cover in October: 32

The months with the most cloud cover are January and February (Cloud cover 51).
The months with the least cloud cover are June and September (Cloud cover 28).

Average visibility in October
Harrisburg, IL

Average visibility in October - Harrisburg, IL
  • Average visibility in October: 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).

Harrisburg, Illinois, USA

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