Monthly outlook for Grant City, IA: average high 85.7°, average low 62.4°. That is 3.1° above the climate normal for August. Precipitation is expected on 4 days (about 0.4 inches), against a normal of 5 days and 2.2 inches. The warmest day looks like 18 August (100.7°), the coolest 21 August (51°).
85.7°/62.4°
Average high / low
+3.1°
Above normal
4 / 5
Wet days / normal
0.4 in
Precipitation this month
Ten-day blocks vs climate normal
Period
Forecast high
Normal
Difference
8 August – 17 August
85°
80.2°
+2.7°
18 August – 27 August
87°
80.4°
+3.7°
28 August – 6 September
at normal
79.2°
—
August records over 66 years
99.7°16 August 1983All-time high
41.9°28 August 1986All-time low
Climate normals and records are computed from the nearest reference point — Lake City (8 mi).
Sun, 0993° / 72°0
93 °
Grant City, Sunday, 9 August
Clear. High 93°, low 72°.
Pressure29.74 inHg
Wind10.6 mph SW
Humidity34%
Visibility6.2 mi
Dew point62°
Mon, 1094° / 71°0
94 °
Grant City, Monday, 10 August
Overcast. High 94°, low 71°.
Pressure29.80 inHg
Wind9.6 mph SE
Humidity54%
Visibility6.2 mi
Dew point67°
Tue, 1198° / 65°0.01
98 °
Grant City, Tuesday, 11 August
Light rain. High 98°, low 65°.
Pressure29.77 inHg
Wind6.9 mph E
Humidity43%
Visibility6.2 mi
Dew point64°
Wed, 1291° / 69°0.04
91 °
Grant City, Wednesday, 12 August
Light rain. High 91°, low 69°.
Pressure29.88 inHg
Wind7.9 mph E
Humidity49%
Visibility6.2 mi
Dew point63°
Thu, 1370° / 60°0.11
70 °
Grant City, Thursday, 13 August
Light rain. High 70°, low 60°.
Pressure29.97 inHg
Wind8.6 mph E
Humidity91%
Visibility—
Dew point62°
Fri, 1482° / 58°0
82 °
Grant City, Friday, 14 August
Overcast. High 82°, low 58°.
Pressure30.09 inHg
Wind14.9 mph E
Humidity42%
Visibility—
Dew point51°
Sat, 1569° / 59°0.04
69 °
Grant City, Saturday, 15 August
Light rain. High 69°, low 59°.
Pressure30.18 inHg
Wind13 mph E
Humidity97%
Visibility—
Dew point62°
Sun, 1680° / 59°0
80 °
Grant City, Sunday, 16 August
Overcast. High 80°, low 59°.
Pressure30.09 inHg
Wind6.4 mph SW
Humidity55%
Visibility—
Dew point60°
Mon, 1794° / 65°0.02
94 °
Grant City, Monday, 17 August
Light rain. High 94°, low 65°.
Pressure30.00 inHg
Wind11.7 mph S
Humidity44%
Visibility—
Dew point61°
Tue, 18101° / 69°0.06
101 °
Grant City, Tuesday, 18 August
Light rain. High 101°, low 69°.
Pressure29.91 inHg
Wind11.3 mph W
Humidity34%
Visibility—
Dew point59°
Wed, 1986° / 64°0.04
86 °
Grant City, Wednesday, 19 August
Light rain. High 86°, low 64°.
Pressure30.06 inHg
Wind13.6 mph N
Humidity48%
Visibility—
Dew point53°
Thu, 2067° / 55°0.05
67 °
Grant City, Thursday, 20 August
Light rain. High 67°, low 55°.
Pressure30.18 inHg
Wind10.2 mph SE
Humidity79%
Visibility—
Dew point53°
Fri, 2179° / 51°0
79 °
Grant City, Friday, 21 August
Overcast. High 79°, low 51°.
Pressure30.03 inHg
Wind16.3 mph SE
Humidity35%
Visibility—
Dew point43°
Sat, 2294° / 60°0.01
94 °
Grant City, Saturday, 22 August
Light rain. High 94°, low 60°.
Pressure29.80 inHg
Wind16.1 mph NW
Humidity31%
Visibility—
Dew point51°
Sun, 2395° / 64°0
95 °
Grant City, Sunday, 23 August
Mostly clear. High 95°, low 64°.
Pressure29.94 inHg
Wind8.8 mph NW
Humidity18%
Visibility—
Dew point37°
From day 17 onward the outlook is built from 60-year climate statistics
Mon, 2481° / 64°0.08
81 °
Grant City, Monday, 24 August
Climate normal for this date — 60-year average.
Average high81°
Average low64°
Average precipitation0.08 in
Chance of precipitation22%
Record high96° (2023)
Record low48° (1966)
Tue, 2580° / 64°0.11
80 °
Grant City, Tuesday, 25 August
Climate normal for this date — 60-year average.
Average high80°
Average low64°
Average precipitation0.11 in
Chance of precipitation33%
Record high94° (2003)
Record low50° (2025)
Wed, 2680° / 64°0.16
80 °
Grant City, Wednesday, 26 August
Climate normal for this date — 60-year average.
Average high80°
Average low64°
Average precipitation0.16 in
Chance of precipitation35%
Record high96° (2024)
Record low51° (2025)
Thu, 2780° / 64°0.1
80 °
Grant City, Thursday, 27 August
Climate normal for this date — 60-year average.
Average high80°
Average low64°
Average precipitation0.1 in
Chance of precipitation32%
Record high94° (2013)
Record low49° (1971)
Fri, 2881° / 63°0.22
81 °
Grant City, Friday, 28 August
Climate normal for this date — 60-year average.
Average high81°
Average low63°
Average precipitation0.22 in
Chance of precipitation33%
Record high97° (1984)
Record low42° (1986)
Sat, 2981° / 63°0.11
81 °
Grant City, Saturday, 29 August
Climate normal for this date — 60-year average.
Average high81°
Average low63°
Average precipitation0.11 in
Chance of precipitation22%
Record high94° (2012)
Record low49° (1988)
Sun, 3079° / 63°0.06
79 °
Grant City, Sunday, 30 August
Climate normal for this date — 60-year average.
Average high79°
Average low63°
Average precipitation0.06 in
Chance of precipitation23%
Record high95° (2012)
Record low47° (2009)
Mon, 3179° / 62°0.1
79 °
Grant City, Monday, 31 August
Climate normal for this date — 60-year average.
Average high79°
Average low62°
Average precipitation0.1 in
Chance of precipitation30%
Record high91° (2012)
Record low47° (2009)
Tue, 0179° / 62°0.08
79 °
Grant City, Tuesday, 1 September
Climate normal for this date — 60-year average.
Average high79°
Average low62°
Average precipitation0.08 in
Chance of precipitation25%
Record high91° (1984)
Record low46° (1967)
Wed, 0279° / 62°0.13
79 °
Grant City, Wednesday, 2 September
Climate normal for this date — 60-year average.
Average high79°
Average low62°
Average precipitation0.13 in
Chance of precipitation38%
Record high94° (2023)
Record low50° (1974)
Thu, 0378° / 62°0.07
78 °
Grant City, Thursday, 3 September
Climate normal for this date — 60-year average.
Average high78°
Average low62°
Average precipitation0.07 in
Chance of precipitation23%
Record high94° (2023)
Record low40° (1974)
Fri, 0478° / 61°0.12
78 °
Grant City, Friday, 4 September
Climate normal for this date — 60-year average.
Average high78°
Average low61°
Average precipitation0.12 in
Chance of precipitation30%
Record high95° (2012)
Record low44° (1974)
Sat, 0578° / 61°0.08
78 °
Grant City, Saturday, 5 September
Climate normal for this date — 60-year average.
Average high78°
Average low61°
Average precipitation0.08 in
Chance of precipitation28%
Record high91° (1960)
Record low41° (1962)
Sun, 0679° / 60°0.06
79 °
Grant City, Sunday, 6 September
Climate normal for this date — 60-year average.
Average high79°
Average low60°
Average precipitation0.06 in
Chance of precipitation17%
Record high94° (2020)
Record low45° (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 Grant City, IA 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 Grant City, IA 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.