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Contents
- Weather in January
- Weather in February
- Weather in March
- Weather in April
- Weather in May
- Weather in June
- Weather in July
- Weather in August
- Weather in September
- Weather in October
- Weather in November
- Weather in December
- Frequently asked questions
- Average temperature
- Average pressure
- Average wind speed
- Average humidity
- Average rainfall
- Average rainfall days
- Average snowfall
- Average snowfall days
- Average daylight
- Average sunshine
- Average sunshine days
- Average UV index
- Average cloud cover
- Average visibility
Weather in January
January, the same as December, in Ottawa, Illinois, is a freezing cold winter month, with an average temperature fluctuating between 17.2°F (-8.2°C) and 29.1°F (-1.6°C). In Ottawa, January is the coldest month, with temperatures averaging a high of 29.1°F (-1.6°C) and a low of 17.2°F (-8.2°C). Weather in January »
Weather in February
The last month of the winter, February, is a cold month in Ottawa, Illinois, with an average temperature fluctuating between 33.4°F (0.8°C) and 20.7°F (-6.3°C). At the onset of February, Ottawa records an average high-temperature of an icy 33.4°F (0.8°C), showing little deviation from the preceding month. Weather in February »
Weather in March
March, the first month of the spring in Ottawa, is a frosty month, with an average temperature fluctuating between 32.4°F (0.2°C) and 46.9°F (8.3°C). In March, the average high-temperature increases from a cold 33.4°F (0.8°C) in February to a frosty 46.9°F (8.3°C). Weather in March »
Weather in April
April is a mild spring month in Ottawa, Illinois, with temperature in the range of an average high of 58.8°F (14.9°C) and an average low of 42.4°F (5.8°C). Ottawa's weather in April shows a rise in the average high-temperature, moving up from March's frosty 46.9°F (8.3°C) to a mild 58.8°F (14.9°C). Weather in April »
Weather in May
May, the last month of the spring in Ottawa, is a pleasant month, with temperature in the range of an average low of 53.6°F (12°C) and an average high of 70.7°F (21.5°C). With the onset of May, the average high-temperature slightly shifts from April's refreshing 58.8°F (14.9°C) to a pleasant 70.7°F (21.5°C). Weather in May »
Weather in June
The first month of the summer, June, is a moderately hot month in Ottawa, Illinois, with temperature in the range of an average low of 61.5°F (16.4°C) and an average high of 78.8°F (26°C). June brings a slight increase in the average high-temperature, progressing from a pleasant 70.7°F (21.5°C) in May to a warm 78.8°F (26°C). Weather in June »
Weather in July
July, the same as June, is a moderately hot summer month in Ottawa, Illinois, with an average temperature ranging between min 64.2°F (17.9°C) and max 81°F (27.2°C). In Ottawa, the month of July registers the highest temperatures, averaging 81°F (27.2°C) at the peak and 64.2°F (17.9°C) at the lowest. July's average heat index is appraised at a hot 87.8°F (31°C). Weather in July »
Weather in August
The last month of the summer, August, is another warm month in Ottawa, Illinois, with temperature in the range of an average high of 79.3°F (26.3°C) and an average low of 62.1°F (16.7°C). As Ottawa welcomes August, the average high-temperature records at a still moderately hot 79.3°F (26.3°C), marking an insignificant deviation from the prior month. Weather in August »
Weather in September
September, the first month of the autumn in Ottawa, is also a moderately hot month, with an average temperature fluctuating between 74.5°F (23.6°C) and 56.1°F (13.4°C). The transition from August to September sees an average high-temperature of a still moderately hot 74.5°F (23.6°C), indicating a minor variance from the prior month. Weather in September »
Weather in October
October, the same as September, is another enjoyable autumn month in Ottawa, Illinois, with an average temperature fluctuating between 45.7°F (7.6°C) and 61.7°F (16.5°C). As September transitions into October, Ottawa sees a drop in the average high-temperature, transitioning from a moderately hot 74.5°F (23.6°C) to a refreshing 61.7°F (16.5°C). Weather in October »
Weather in November
The last month of the autumn, November, is also a frosty month in Ottawa, Illinois, with an average temperature ranging between min 33.8°F (1°C) and max 47.1°F (8.4°C). The shift from October to November is characterized by a clear decrease in the average high-temperature, reducing from a comfortable 61.7°F (16.5°C) to a chilly 47.1°F (8.4°C). Weather in November »
Weather in December
December, the first month of the winter in Ottawa, is also a wintry month, with temperature in the range of an average high of 35.1°F (1.7°C) and an average low of 25°F (-3.9°C). December's onset corresponds with a shift in the average high-temperature, moving from a frosty 47.1°F (8.4°C) in November to a cold 35.1°F (1.7°C). Weather in December »
Updated: Jun 22, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What is the coldest month?
January proves to be the coldest month in Ottawa, recording an average maximum temperature of 29.1°F (-1.6°C) and a minimum temperature of 17.2°F (-8.2°C).
How much does it rain?
In Ottawa, Illinois, during the entire year, the rain falls for 166.3 days and collects up to 35.35" (898mm) of precipitation.
When does it snow?
January through April, October through December are months with snowfall.
How much does it snow in Ottawa?
In Ottawa, during the entire year, snow falls for 43.4 days and aggregates up to 17.76" (451mm) of snow.
What is the month with the least sunshine?
With an average of 3.9h of sunshine, January has the least sunshine of the year.
What is the month with the lowest UV index in Ottawa?
The months with the lowest UV index are January and December, with an average maximum UV index of 1.
What is the snowiest month?
February is the month with the most snowfall. Snow falls for 10.4 days and accumulates 5.08" (129mm) of snow.
When is Daylight Saving Time (DST)?
On Sunday, March 10. 2024, at 2:00 am, Daylight Saving Time starts, and the time zone changes from CST to CDT. Daylight Saving Time ends Sunday, November 3. 2024, at 2:00 am, and the time zone reverts from CDT to CST.
What is the wettest month?
The month with the most rainfall is May, when the rain falls for 19.4 days and typically aggregates up to 5" (127mm) of precipitation.
When it does not snow?
May through September are months without snowfall.
When are the longest days?
With an average of 15h and 6min of daylight, June has the longest days of the year.
What month has the most sunshine?
June has the most sunshine of the year, with an average of 9.8h of sunshine.
What are the months with the highest UV index?
The months with the highest UV index are June and July, with an average maximum UV index of 6.
What time of the year is the hottest?
Ottawa notes the warmest temperatures in July, with a average high of 81°F (27.2°C) and a low of 64.2°F (17.9°C).
What is the most humid month?
The most humid month is July, with an average relative humidity of 85%.
What is the least humid month?
October is the least humid month, with an average relative humidity of 72%.
What is the driest month?
The month with the least rainfall is November, when the rain falls for 10.2 days and typically collects 1.81" (46mm) of precipitation.
What is the month with the shortest days?
December has the shortest days of the year, with an average of 9h and 12min of daylight.
Average temperature
Ottawa, IL
The warmest month (with the highest average high temperature) is July (81°F).
The month with the lowest average high temperature is January (29.1°F).
The month with the highest average low temperature is July (64.2°F).
The coldest month (with the lowest average low temperature) is January (17.2°F).
Average pressure
Ottawa, IL
- Average pressure in January:
30.13"Hg - Average pressure in February:
30.11"Hg - Average pressure in March:
30.08"Hg - Average pressure in April:
29.94"Hg - Average pressure in May:
29.96"Hg - Average pressure in June:
29.92"Hg
- Average pressure in July:
29.97"Hg - Average pressure in August:
29.98"Hg - Average pressure in September:
30.03"Hg - Average pressure in October:
30.01"Hg - Average pressure in November:
30.1"Hg - Average pressure in December:
30.1"Hg
The month with the highest atmospheric pressure is January (30.13"Hg).
The month with the lowest atmospheric pressure is June (29.92"Hg).
Average wind speed
Ottawa, IL
- Average wind speed in January:
10.1mph - Average wind speed in February:
10.1mph - Average wind speed in March:
9.8mph - Average wind speed in April:
10.2mph - Average wind speed in May:
8.7mph - Average wind speed in June:
7.5mph
- Average wind speed in July:
6.3mph - Average wind speed in August:
6.2mph - Average wind speed in September:
7.3mph - Average wind speed in October:
9.1mph - Average wind speed in November:
9.8mph - Average wind speed in December:
9.5mph
The windiest month (with the highest average wind speed) is April (10.2mph).
The calmest month (with the lowest average wind speed) is August (6.2mph).
Average humidity
Ottawa, IL
The month with the highest relative humidity is July (85%).
The month with the lowest relative humidity is October (72%).
Average rainfall
Ottawa, IL
- Average rainfall in January:
1.85" - Average rainfall in February:
1.85" - Average rainfall in March:
2.24" - Average rainfall in April:
4.25" - Average rainfall in May:
5" - Average rainfall in June:
4.13"
- Average rainfall in July:
3.7" - Average rainfall in August:
2.95" - Average rainfall in September:
2.52" - Average rainfall in October:
3.11" - Average rainfall in November:
1.81" - Average rainfall in December:
1.93"
The wettest month (with the highest rainfall) is May (5").
The driest month (with the least rainfall) is November (1.81").
Average rainfall days
Ottawa, IL
- Average rainfall days in January:
6.5 days - Average rainfall days in February:
6.2 days - Average rainfall days in March:
13.6 days - Average rainfall days in April:
17.6 days - Average rainfall days in May:
19.4 days - Average rainfall days in June:
19.4 days
- Average rainfall days in July:
19.9 days - Average rainfall days in August:
18.3 days - Average rainfall days in September:
13.4 days - Average rainfall days in October:
13.3 days - Average rainfall days in November:
10.2 days - Average rainfall days in December:
8.5 days
The month with the highest number of rainy days is July (19.9 days).
The month with the least rainy days is February (6.2 days).
Average snowfall
Ottawa, IL
The month with the highest snowfall is February (5.08").
The months with the least snowfall are May, June, July, August and September (0").
Average snowfall days
Ottawa, IL
- Average snowfall days in January:
12.9 days - Average snowfall days in February:
10.4 days - Average snowfall days in March:
5.8 days - Average snowfall days in April:
1.7 days - Average snowfall days in May:
0 days - Average snowfall days in June:
0 days
- Average snowfall days in July:
0 days - Average snowfall days in August:
0 days - Average snowfall days in September:
0 days - Average snowfall days in October:
0.3 days - Average snowfall days in November:
3.2 days - Average snowfall days in December:
9.1 days
The month with the highest number of snowfall days is January (12.9 days).
The months with the least snowfall days are May, June, July, August and September (0 days).
Average daylight / Average sunshine
Ottawa, IL
- Average daylight in January:
9h and 4min - Average daylight in February:
10h and 4min - Average daylight in March:
12h and 0min - Average daylight in April:
13h and 2min - Average daylight in May:
14h and 3min - Average daylight in June:
15h and 1min
- Average daylight in July:
14h and 5min - Average daylight in August:
13h and 5min - Average daylight in September:
12h and 3min - Average daylight in October:
11h and 1min - Average daylight in November:
9h and 5min - Average daylight in December:
9h and 1min
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 12min).
- Average sunshine in January:
3h and 5min - Average sunshine in February:
4h and 1min - Average sunshine in March:
6h and 2min - Average sunshine in April:
7h and 5min - Average sunshine in May:
8h and 5min - Average sunshine in June:
9h and 5min
- Average sunshine in July:
9h and 4min - Average sunshine in August:
9h and 4min - Average sunshine in September:
8h and 5min - Average sunshine in October:
5h and 5min - Average sunshine in November:
5h and 1min - Average sunshine in December:
4h and 1min
The month with the most sunshine is June (Average sunshine: 9h and 48min).
The month with the least sunshine is January (Average sunshine: 3h and 54min).
Average sunshine days
Ottawa, IL
- Average sunshine days in January:
13.2 days - Average sunshine days in February:
12.3 days - Average sunshine days in March:
13.3 days - Average sunshine days in April:
9.8 days - Average sunshine days in May:
9.1 days - Average sunshine days in June:
8.2 days
- Average sunshine days in July:
7.2 days - Average sunshine days in August:
9.9 days - Average sunshine days in September:
13.2 days - Average sunshine days in October:
15.4 days - Average sunshine days in November:
17 days - Average sunshine days in December:
15.3 days
The month with the most sunshine days is November (17 days).
The month with the least sunshine days is July (7.2 days).
Average UV index
Ottawa, IL
The months with the highest UV index are June and July (UV index 6).
The months with the lowest UV index are January and December (UV index 1).
Average cloud cover
Ottawa, IL
The month with the most cloud cover is January (Cloud cover 59).
The month with the least cloud cover is September (Cloud cover 32).
Average visibility
Ottawa, IL
The months with the highest visibility are March, April, May, June, September, October, November and December (6mi).
The months with the lowest visibility are January, February, July and August (5mi).
Ottawa, Illinois, USA
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