As of 21:12 CDT

Weather in Grafton, IL

81°Current weather

Grafton, Saturday, 8 August, 21:12

Clear. Feels like 88°. High 89°, low 69°.

Pressure30.00 inHg
Wind8.2 mph E
Humidity80%
Visibility6.2 mi
Dew point74°

Monthly outlook for Grafton, IL: average high 85°, average low 67.9°. That is 0.4° above the climate normal for August. Precipitation is expected on 8 days (about 2.7 inches), against a normal of 5 days and 1.5 inches. The warmest day looks like 11 August (101.3°), the coolest 21 August (56.3°).

85°/67.9°
Average high / low
+0.4°
Above normal
8 / 5
Wet days / normal
2.7 in
Precipitation this month

Ten-day blocks vs climate normal

PeriodForecast highNormalDifference
8 August – 17 August86.9°84.2°+1.5°
18 August – 27 August81.8°84.5°-1.5°
28 August – 6 Septemberat normal82.6°

August records over 66 years

100.9°14 August 2007All-time high
48.2°29 August 1986All-time low

Climate normals and records are computed from the nearest reference point — Jerseyville (11 mi).

Sun, 0995° / 72°0Partly cloudy
95 °Partly cloudy

Grafton, Sunday, 9 August

Partly cloudy. High 95°, low 72°.

Pressure29.94 inHg
Wind12.9 mph SW
Humidity55%
Visibility6.2 mi
Dew point72°
Mon, 1099° / 76°0.02Light rain
99 °Light rain

Grafton, Monday, 10 August

Light rain. High 99°, low 76°.

Pressure29.94 inHg
Wind12.2 mph SW
Humidity49%
Visibility6.2 mi
Dew point70°
Tue, 11101° / 76°0.03Light rain
101 °Light rain

Grafton, Tuesday, 11 August

Light rain. High 101°, low 76°.

Pressure29.85 inHg
Wind12.7 mph SW
Humidity46%
Visibility6.2 mi
Dew point70°
Wed, 1287° / 74°0.19Light rain
87 °Light rain

Grafton, Wednesday, 12 August

Light rain. High 87°, low 74°.

Pressure29.85 inHg
Wind3.8 mph NW
Humidity72%
Visibility6.2 mi
Dew point71°
Thu, 1384° / 67°1.3Heavy rain
84 °Heavy rain

Grafton, Thursday, 13 August

Heavy rain. High 84°, low 67°.

Pressure29.91 inHg
Wind14.8 mph E
Humidity66%
Visibility
Dew point69°
Fri, 1475° / 67°0.48Rain
75 °Rain

Grafton, Friday, 14 August

Rain. High 75°, low 67°.

Pressure30.03 inHg
Wind10.7 mph E
Humidity84%
Visibility
Dew point68°
Sat, 1577° / 67°0.24Light rain
77 °Light rain

Grafton, Saturday, 15 August

Light rain. High 77°, low 67°.

Pressure30.15 inHg
Wind16.4 mph SE
Humidity73%
Visibility
Dew point66°
Sun, 1679° / 66°0.04Light rain
79 °Light rain

Grafton, Sunday, 16 August

Light rain. High 79°, low 66°.

Pressure30.06 inHg
Wind11.6 mph E
Humidity82%
Visibility
Dew point70°
Mon, 1781° / 68°0.13Light rain
81 °Light rain

Grafton, Monday, 17 August

Light rain. High 81°, low 68°.

Pressure30.03 inHg
Wind7.2 mph NE
Humidity78%
Visibility
Dew point69°
Tue, 1882° / 68°0.05Light rain
82 °Light rain

Grafton, Tuesday, 18 August

Light rain. High 82°, low 68°.

Pressure30.00 inHg
Wind9.7 mph SW
Humidity83%
Visibility
Dew point72°
Wed, 1984° / 69°0Overcast
84 °Overcast

Grafton, Wednesday, 19 August

Overcast. High 84°, low 69°.

Pressure29.91 inHg
Wind12 mph NE
Humidity63%
Visibility
Dew point68°
Thu, 2075° / 59°0Partly cloudy
75 °Partly cloudy

Grafton, Thursday, 20 August

Partly cloudy. High 75°, low 59°.

Pressure30.03 inHg
Wind12.7 mph NE
Humidity57%
Visibility
Dew point56°
Fri, 2173° / 56°0.02Light rain
73 °Light rain

Grafton, Friday, 21 August

Light rain. High 73°, low 56°.

Pressure30.03 inHg
Wind12.1 mph E
Humidity55%
Visibility
Dew point54°
Sat, 2285° / 62°0.19Light rain
85 °Light rain

Grafton, Saturday, 22 August

Light rain. High 85°, low 62°.

Pressure29.83 inHg
Wind13 mph SE
Humidity60%
Visibility
Dew point65°
Sun, 2392° / 70°0Clear
92 °Clear

Grafton, Sunday, 23 August

Clear. High 92°, low 70°.

Pressure29.94 inHg
Wind8.5 mph NE
Humidity54%
Visibility
Dew point68°
From day 17 onward the outlook is built from 60-year climate statistics
Mon, 2484° / 67°0.09Climate normal
84 °Climate normal

Grafton, Monday, 24 August

Climate normal for this date — 60-year average.

Average high84°
Average low67°
Average precipitation0.09 in
Chance of precipitation28%
Record high98° (2023)
Record low56° (2017)
Tue, 2585° / 68°0.06Climate normal
85 °Climate normal

Grafton, Tuesday, 25 August

Climate normal for this date — 60-year average.

Average high85°
Average low68°
Average precipitation0.06 in
Chance of precipitation27%
Record high96° (2023)
Record low56° (2025)
Wed, 2685° / 68°0.12Climate normal
85 °Climate normal

Grafton, Wednesday, 26 August

Climate normal for this date — 60-year average.

Average high85°
Average low68°
Average precipitation0.12 in
Chance of precipitation30%
Record high97° (2003)
Record low52° (2025)
Thu, 2785° / 69°0.11Climate normal
85 °Climate normal

Grafton, Thursday, 27 August

Climate normal for this date — 60-year average.

Average high85°
Average low69°
Average precipitation0.11 in
Chance of precipitation28%
Record high96° (1983)
Record low56° (2015)
Fri, 2885° / 68°0.09Climate normal
85 °Climate normal

Grafton, Friday, 28 August

Climate normal for this date — 60-year average.

Average high85°
Average low68°
Average precipitation0.09 in
Chance of precipitation28%
Record high96° (1990)
Record low54° (1986)
Sat, 2984° / 67°0.06Climate normal
84 °Climate normal

Grafton, Saturday, 29 August

Climate normal for this date — 60-year average.

Average high84°
Average low67°
Average precipitation0.06 in
Chance of precipitation25%
Record high97° (1984)
Record low48° (1986)
Sun, 3083° / 67°0.11Climate normal
83 °Climate normal

Grafton, Sunday, 30 August

Climate normal for this date — 60-year average.

Average high83°
Average low67°
Average precipitation0.11 in
Chance of precipitation28%
Record high96° (2013)
Record low51° (1986)
Mon, 3183° / 67°0.1Climate normal
83 °Climate normal

Grafton, Monday, 31 August

Climate normal for this date — 60-year average.

Average high83°
Average low67°
Average precipitation0.1 in
Chance of precipitation27%
Record high99° (2013)
Record low54° (2023)
Tue, 0183° / 67°0.13Climate normal
83 °Climate normal

Grafton, Tuesday, 1 September

Climate normal for this date — 60-year average.

Average high83°
Average low67°
Average precipitation0.13 in
Chance of precipitation32%
Record high97° (2011)
Record low51° (1967)
Wed, 0282° / 66°0.13Climate normal
82 °Climate normal

Grafton, Wednesday, 2 September

Climate normal for this date — 60-year average.

Average high82°
Average low66°
Average precipitation0.13 in
Chance of precipitation33%
Record high96° (2011)
Record low51° (2017)
Thu, 0382° / 66°0.07Climate normal
82 °Climate normal

Grafton, Thursday, 3 September

Climate normal for this date — 60-year average.

Average high82°
Average low66°
Average precipitation0.07 in
Chance of precipitation25%
Record high93° (2011)
Record low49° (1974)
Fri, 0481° / 65°0.1Climate normal
81 °Climate normal

Grafton, Friday, 4 September

Climate normal for this date — 60-year average.

Average high81°
Average low65°
Average precipitation0.1 in
Chance of precipitation23%
Record high94° (1960)
Record low50° (1974)
Sat, 0582° / 65°0.04Climate normal
82 °Climate normal

Grafton, Saturday, 5 September

Climate normal for this date — 60-year average.

Average high82°
Average low65°
Average precipitation0.04 in
Chance of precipitation15%
Record high94° (1998)
Record low51° (1974)
Sun, 0681° / 65°0.05Climate normal
81 °Climate normal

Grafton, Sunday, 6 September

Climate normal for this date — 60-year average.

Average high81°
Average low65°
Average precipitation0.05 in
Chance of precipitation22%
Record high96° (1990)
Record low52° (2017)

About the monthly outlook

How accurate is a 30-day forecast?

The first 16 days come from weather models — reliable for the first 3–5 days and progressively less so after that. Days 17 through 30 for Grafton, IL are built from the climate normal, the 60-year average, so they show typical weather for those dates rather than a specific forecast.

What does "above normal" mean?

We compare the forecast against the climate normal for those exact calendar days, computed from 60 years of observations. The deviation shows how much the coming month differs from a typical one.

Where do the 66-year records come from?

They are real temperature extremes recorded in Grafton, IL since 1960: the highest and lowest reading for each calendar date, with the year it happened.

How often is it updated?

The forecast portion refreshes every hour; the climate portion is based on long-term data and stays stable.