Monthly outlook for Grafton, WI: average high 75.7°, average low 61.4°. That is 0° below the climate normal for August. Precipitation is expected on 3 days (about 2.5 inches), against a normal of 6 days and 2.0 inches. The warmest day looks like 10 August (84.9°), the coolest 20 August (55.8°).
75.7°/61.4°
Average high / low
−0°
Below normal
3 / 6
Wet days / normal
2.5 in
Precipitation this month
Ten-day blocks vs climate normal
Period
Forecast high
Normal
Difference
8 August – 17 August
77.4°
76.1°
+0.7°
18 August – 27 August
73°
75.4°
-1.3°
28 August – 6 September
at normal
74.1°
—
August records over 66 years
96.3°23 August 2023All-time high
50.9°26 August 2025All-time low
Sun, 0976° / 64°1.24
76 °
Grafton, Sunday, 9 August
Heavy rain. High 76°, low 64°.
Pressure29.97 inHg
Wind7.5 mph W
Humidity95%
Visibility2.7 mi
Dew point67°
Mon, 1085° / 68°0.02
85 °
Grafton, Monday, 10 August
Light rain. High 85°, low 68°.
Pressure29.94 inHg
Wind4.2 mph SE
Humidity70%
Visibility6.2 mi
Dew point68°
Tue, 1175° / 65°0.67
75 °
Grafton, Tuesday, 11 August
Heavy rain. High 75°, low 65°.
Pressure29.80 inHg
Wind7.2 mph E
Humidity89%
Visibility6.2 mi
Dew point69°
Wed, 1280° / 63°0
80 °
Grafton, Wednesday, 12 August
Light rain. High 80°, low 63°.
Pressure29.85 inHg
Wind7.2 mph NW
Humidity65%
Visibility6.2 mi
Dew point65°
Thu, 1372° / 60°0
72 °
Grafton, Thursday, 13 August
Overcast. High 72°, low 60°.
Pressure30.03 inHg
Wind9.3 mph SW
Humidity52%
Visibility—
Dew point50°
Fri, 1477° / 58°0
77 °
Grafton, Friday, 14 August
Clear. High 77°, low 58°.
Pressure30.12 inHg
Wind7.3 mph W
Humidity44%
Visibility—
Dew point50°
Sat, 1573° / 61°0
73 °
Grafton, Saturday, 15 August
Overcast. High 73°, low 61°.
Pressure30.27 inHg
Wind8.7 mph SE
Humidity56%
Visibility—
Dew point55°
Sun, 1674° / 58°0
74 °
Grafton, Sunday, 16 August
Overcast. High 74°, low 58°.
Pressure30.15 inHg
Wind6.9 mph SE
Humidity58%
Visibility—
Dew point56°
Mon, 1780° / 62°0
80 °
Grafton, Monday, 17 August
Partly cloudy. High 80°, low 62°.
Pressure30.03 inHg
Wind6.3 mph SW
Humidity56%
Visibility—
Dew point60°
Tue, 1884° / 67°0.03
84 °
Grafton, Tuesday, 18 August
Light rain. High 84°, low 67°.
Pressure29.91 inHg
Wind14.5 mph SW
Humidity60%
Visibility—
Dew point65°
Wed, 1972° / 62°0.01
72 °
Grafton, Wednesday, 19 August
Light rain. High 72°, low 62°.
Pressure29.88 inHg
Wind18.5 mph NW
Humidity55%
Visibility—
Dew point55°
Thu, 2072° / 56°0
72 °
Grafton, Thursday, 20 August
Overcast. High 72°, low 56°.
Pressure30.06 inHg
Wind10.9 mph N
Humidity43%
Visibility—
Dew point45°
Fri, 2171° / 56°0
71 °
Grafton, Friday, 21 August
Clear. High 71°, low 56°.
Pressure30.09 inHg
Wind8.6 mph E
Humidity49%
Visibility—
Dew point49°
Sat, 2263° / 58°0.44
63 °
Grafton, Saturday, 22 August
Rain. High 63°, low 58°.
Pressure29.91 inHg
Wind12.3 mph SE
Humidity95%
Visibility—
Dew point58°
Sun, 2377° / 61°0.02
77 °
Grafton, Sunday, 23 August
Light rain. High 77°, low 61°.
Pressure29.85 inHg
Wind15.7 mph W
Humidity54%
Visibility—
Dew point55°
From day 17 onward the outlook is built from 60-year climate statistics
Mon, 2475° / 66°0.13
75 °
Grafton, Monday, 24 August
Climate normal for this date — 60-year average.
Average high75°
Average low66°
Average precipitation0.13 in
Chance of precipitation30%
Record high93° (2020)
Record low57° (1966)
Tue, 2576° / 67°0.09
76 °
Grafton, Tuesday, 25 August
Climate normal for this date — 60-year average.
Average high76°
Average low67°
Average precipitation0.09 in
Chance of precipitation27%
Record high89° (2021)
Record low52° (2025)
Wed, 2676° / 67°0.15
76 °
Grafton, Wednesday, 26 August
Climate normal for this date — 60-year average.
Average high76°
Average low67°
Average precipitation0.15 in
Chance of precipitation35%
Record high92° (2020)
Record low51° (2025)
Thu, 2776° / 67°0.13
76 °
Grafton, Thursday, 27 August
Climate normal for this date — 60-year average.
Average high76°
Average low67°
Average precipitation0.13 in
Chance of precipitation42%
Record high90° (2020)
Record low53° (2025)
Fri, 2876° / 66°0.11
76 °
Grafton, Friday, 28 August
Climate normal for this date — 60-year average.
Average high76°
Average low66°
Average precipitation0.11 in
Chance of precipitation37%
Record high90° (2021)
Record low51° (1986)
Sat, 2976° / 66°0.11
76 °
Grafton, Saturday, 29 August
Climate normal for this date — 60-year average.
Average high76°
Average low66°
Average precipitation0.11 in
Chance of precipitation35%
Record high87° (2022)
Record low52° (2025)
Sun, 3074° / 66°0.07
74 °
Grafton, Sunday, 30 August
Climate normal for this date — 60-year average.
Average high74°
Average low66°
Average precipitation0.07 in
Chance of precipitation35%
Record high84° (2013)
Record low52° (2023)
Mon, 3174° / 65°0.04
74 °
Grafton, Monday, 31 August
Climate normal for this date — 60-year average.
Average high74°
Average low65°
Average precipitation0.04 in
Chance of precipitation17%
Record high84° (2022)
Record low52° (2025)
Tue, 0174° / 65°0.07
74 °
Grafton, Tuesday, 1 September
Climate normal for this date — 60-year average.
Average high74°
Average low65°
Average precipitation0.07 in
Chance of precipitation28%
Record high84° (2022)
Record low55° (2017)
Wed, 0274° / 65°0.06
74 °
Grafton, Wednesday, 2 September
Climate normal for this date — 60-year average.
Average high74°
Average low65°
Average precipitation0.06 in
Chance of precipitation27%
Record high87° (2023)
Record low52° (2025)
Thu, 0374° / 65°0.09
74 °
Grafton, Thursday, 3 September
Climate normal for this date — 60-year average.
Average high74°
Average low65°
Average precipitation0.09 in
Chance of precipitation23%
Record high93° (2023)
Record low52° (1974)
Fri, 0473° / 64°0.07
73 °
Grafton, Friday, 4 September
Climate normal for this date — 60-year average.
Average high73°
Average low64°
Average precipitation0.07 in
Chance of precipitation25%
Record high88° (2023)
Record low45° (2025)
Sat, 0573° / 64°0.09
73 °
Grafton, Saturday, 5 September
Climate normal for this date — 60-year average.
Average high73°
Average low64°
Average precipitation0.09 in
Chance of precipitation25%
Record high85° (2023)
Record low49° (2019)
Sun, 0673° / 64°0.08
73 °
Grafton, Sunday, 6 September
Climate normal for this date — 60-year average.
Average high73°
Average low64°
Average precipitation0.08 in
Chance of precipitation35%
Record high85° (1990)
Record low47° (2025)
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, WI 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, WI 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.