Climate and monthly weather forecastGrafton, IL
Climate and monthly weather forecast
Weather in January
January, the same as December, is a wintry winter month in Grafton, Illinois, with temperature in the range of an average low of 23.4°F (-4.8°C) and an average high of 36.1°F (2.3°C). January, on average, is the coldest month, registering a high temperature of 36.1°F (2.3°C) and a low of 23.4°F (-4.8°C). Weather in January »Weather in February
The last month of the winter, February, is another cold month in Grafton, Illinois, with an average temperature varying between 41°F (5°C) and 27°F (-2.8°C). Grafton's weather, upon February's arrival, documents an average high-temperature of a still icy 41°F (5°C), nearly identical to the prior month. Weather in February »Weather in March
The first month of the spring, March, is a cool month in Grafton, Illinois, with an average temperature fluctuating between 37.6°F (3.1°C) and 53.6°F (12°C). An increase in the average high-temperature marks March, moving from February's wintry 41°F (5°C) to a cool 53.6°F (12°C). Weather in March »Weather in April
April is an enjoyable spring month in Grafton, Illinois, with an average temperature ranging between max 64.9°F (18.3°C) and min 47.1°F (8.4°C). April's onset brings a temperature rise, moving from a cool 53.6°F (12°C) in March to a refreshing 64.9°F (18.3°C). Weather in April »Weather in May
The last month of the spring, May, is a moderately hot month in Grafton, Illinois, with an average temperature varying between 56.8°F (13.8°C) and 74.1°F (23.4°C). The onset of May brings a temperature shift, with the average high-temperature moving from a refreshing 64.9°F (18.3°C) in April to a warm 74.1°F (23.4°C). Weather in May »Weather in June
The first month of the summer, June, is also a moderately hot month in Grafton, Illinois, with an average temperature ranging between min 65.8°F (18.8°C) and max 83.3°F (28.5°C). Observing a rise in June, the average high-temperature goes from May's warm 74.1°F (23.4°C) to a still moderately hot 83.3°F (28.5°C). Weather in June »Weather in July
July in Grafton, Illinois, is a hot summer month, with an average temperature ranging between max 86.4°F (30.2°C) and min 68.2°F (20.1°C). In Grafton, July records the highest average temperatures, peaking at 86.4°F (30.2°C) and reaching a low of 68.2°F (20.1°C). For most parts of July, the heat index is evaluated at a sweltering 100.4°F (38°C). Weather in July »Weather in August
The last month of the summer, August, is another warm month in Grafton, Illinois, with an average temperature varying between 66.4°F (19.1°C) and 84.9°F (29.4°C). Entering August, the average high-temperature is recorded at a moderately hot 84.9°F (29.4°C), exhibiting a minimal shift from July's 86.4°F (30.2°C). Weather in August »Weather in September
September, the first month of the autumn in Grafton, is also a moderately hot month, with an average temperature varying between 79.2°F (26.2°C) and 59.7°F (15.4°C). September witnesses a gentle descent in average high-temperature, descending from August's moderately hot 84.9°F (29.4°C) to a still warm 79.2°F (26.2°C). Weather in September »Weather in October
October, like September, in Grafton, Illinois, is another refreshing autumn month, with an average temperature varying between 65.8°F (18.8°C) and 48.6°F (9.2°C). Grafton's October weather shows a moderate shift in high-temperatures, falling from September's warm 79.2°F (26.2°C) to an enjoyable 65.8°F (18.8°C). Weather in October »Weather in November
November, the last month of the autumn in Grafton, is also a fresh month, with an average temperature ranging between min 37.6°F (3.1°C) and max 52.7°F (11.5°C). The beginning of November involves a decrease in the average high-temperature, transitioning from a refreshing 65.8°F (18.8°C) in October to a cool 52.7°F (11.5°C). Weather in November »Weather in December
December, the first month of the winter in Grafton, is also an icy month, with temperature in the range of an average low of 30°F (-1.1°C) and an average high of 41.5°F (5.3°C). Start of December brings a shift in the average high-temperature, falling from November's cool 52.7°F (11.5°C) to an icy 41.5°F (5.3°C). Weather in December »Updated: Feb 12, 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
Grafton's temperature records reveal January as the coldest month, marked by average highs of 36.1°F (2.3°C) and lows of 23.4°F (-4.8°C).
Throughout the year, there are 138.8 rainfall days, and 27.6" (701mm) of precipitation is accumulated.
January through March, November and December are months with snowfall in Grafton, Illinois.
The months with the most snowfall in Grafton, Illinois, are January and February, with an average 1.54" (39mm) of accumulated snow.
Throughout the year, in Grafton, Illinois, there are 17.9 snowfall days, and 5.12" (130mm) of snow is accumulated.
January and February, with an average of 4.6h of sunshine, are months with the least sunshine.
The months with the lowest UV index are January, February, November and December, with an average maximum UV index of 2.
The month with the least rainfall is February, when the rain falls for 6.6 days and typically collects 1.3" (33mm) of precipitation.
On Sunday, March 10. 2024, at 2:00 am, Daylight Saving Time starts in Grafton, Illinois, 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.
In Grafton, snow does not fall in April through October.
The most humid month in Grafton is May, with an average relative humidity of 79%.
The month with the most rainfall in Grafton is May, when the rain falls for 15.9 days and typically aggregates up to 3.35" (85mm) of precipitation.
May through August, with an average maximum UV index of 6, are months with the highest UV index in Grafton, Illinois.
With an average of 14h and 54min of daylight, June has the longest days of the year in Grafton, Illinois.
The months with the most sunshine are June and July, with an average of 10.4h of sunshine.
Grafton records the warmest temperatures in July, averaging a high of 86.4°F (30.2°C) and a low of 68.2°F (20.1°C).
With an average relative humidity of 71%, October is the least humid month in Grafton.
With an average of 9h and 30min of daylight, December has the shortest days of the year.
Average temperature
Grafton, IL
The warmest month (with the highest average high temperature) is July (86.4°F).
The month with the lowest average high temperature is January (36.1°F).
The month with the highest average low temperature is July (68.2°F).
The coldest month (with the lowest average low temperature) is January (23.4°F).
Average pressure
Grafton, IL
- Average pressure in January:
30.16"Hg - Average pressure in February:
30.12"Hg - Average pressure in March:
30.07"Hg - Average pressure in April:
29.93"Hg - Average pressure in May:
29.95"Hg - Average pressure in June:
29.92"Hg
- Average pressure in July:
29.97"Hg - Average pressure in August:
29.97"Hg - Average pressure in September:
30.02"Hg - Average pressure in October:
30.03"Hg - Average pressure in November:
30.12"Hg - Average pressure in December:
30.13"Hg
The month with the highest atmospheric pressure is January (30.16"Hg).
The month with the lowest atmospheric pressure is June (29.92"Hg).
Average wind speed
Grafton, IL
- Average wind speed in January:
9.4mph - Average wind speed in February:
9.3mph - Average wind speed in March:
9.1mph - Average wind speed in April:
9.1mph - Average wind speed in May:
7.4mph - Average wind speed in June:
6.5mph
- Average wind speed in July:
5.7mph - Average wind speed in August:
5.7mph - Average wind speed in September:
6.2mph - Average wind speed in October:
8mph - Average wind speed in November:
8.8mph - Average wind speed in December:
8.8mph
The windiest month (with the highest average wind speed) is January (9.4mph).
The calmest months (with the lowest average wind speed) are July and August (5.7mph).
Average humidity
Grafton, IL
The month with the highest relative humidity is May (79%).
The month with the lowest relative humidity is October (71%).
Average rainfall
Grafton, IL
- Average rainfall in January:
1.46" - Average rainfall in February:
1.3" - Average rainfall in March:
2.05" - Average rainfall in April:
3.11" - Average rainfall in May:
3.35" - Average rainfall in June:
3.19"
- Average rainfall in July:
2.68" - Average rainfall in August:
2.99" - Average rainfall in September:
2.01" - Average rainfall in October:
2.44" - Average rainfall in November:
1.54" - Average rainfall in December:
1.5"
The wettest month (with the highest rainfall) is May (3.35").
The driest month (with the least rainfall) is February (1.3").
Average rainfall days
Grafton, IL
- Average rainfall days in January:
6.3 days - Average rainfall days in February:
6.6 days - Average rainfall days in March:
13.4 days - Average rainfall days in April:
13.7 days - Average rainfall days in May:
15.9 days - Average rainfall days in June:
15.1 days
- Average rainfall days in July:
16.3 days - Average rainfall days in August:
13.6 days - Average rainfall days in September:
11.6 days - Average rainfall days in October:
10.4 days - Average rainfall days in November:
9.1 days - Average rainfall days in December:
6.8 days
The month with the highest number of rainy days is July (16.3 days).
The month with the least rainy days is January (6.3 days).
Average snowfall
Grafton, IL
The months with the highest snowfall are January and February (1.54").
The months with the least snowfall are April, May, June, July, August, September and October (0").
Average snowfall days
Grafton, IL
- Average snowfall days in January:
5.7 days - Average snowfall days in February:
4.8 days - Average snowfall days in March:
1.8 days - Average snowfall days in April:
0.3 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:
0.1 days - Average snowfall days in November:
1.3 days - Average snowfall days in December:
3.9 days
The month with the highest number of snowfall days is January (5.7 days).
The months with the least snowfall days are May, June, July, August and September (0 days).
Average daylight / Average sunshine
Grafton, IL
- Average daylight in January:
9h and 48min - Average daylight in February:
10h and 48min - Average daylight in March:
12h and 0min - Average daylight in April:
13h and 18min - Average daylight in May:
14h and 18min - Average daylight in June:
14h and 54min
- Average daylight in July:
14h and 36min - Average daylight in August:
13h and 36min - Average daylight in September:
12h and 24min - Average daylight in October:
11h and 12min - Average daylight in November:
10h and 6min - Average daylight in December:
9h and 30min
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 30min).
- Average sunshine in January:
4h and 36min - Average sunshine in February:
4h and 36min - Average sunshine in March:
6h and 30min - Average sunshine in April:
8h and 30min - Average sunshine in May:
9h and 18min - Average sunshine in June:
10h and 24min
- Average sunshine in July:
10h and 24min - Average sunshine in August:
10h and 12min - Average sunshine in September:
9h and 24min - Average sunshine in October:
6h and 0min - Average sunshine in November:
5h and 30min - Average sunshine in December:
4h and 48min
The months with the most sunshine are June and July (Average sunshine: 10h and 24min).
The months with the least sunshine are January and February (Average sunshine: 4h and 36min).
Average sunshine days
Grafton, IL
- Average sunshine days in January:
19.3 days - Average sunshine days in February:
16.1 days - Average sunshine days in March:
15.2 days - Average sunshine days in April:
15 days - Average sunshine days in May:
12.7 days - Average sunshine days in June:
11.2 days
- Average sunshine days in July:
12.7 days - Average sunshine days in August:
14.3 days - Average sunshine days in September:
16.4 days - Average sunshine days in October:
19.4 days - Average sunshine days in November:
19.2 days - Average sunshine days in December:
19.8 days
The month with the most sunshine days is December (19.8 days).
The month with the least sunshine days is June (11.2 days).
Average UV index
Grafton, IL
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, November and December (UV index 2).
Average cloud cover
Grafton, IL
The month with the most cloud cover is January (Cloud cover 51).
The month with the least cloud cover is August (Cloud cover 28).
Average visibility
Grafton, IL
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).
