Monthly outlook for Harmony, IL: average high 76.4°, average low 60.6°. That is 1.9° below the climate normal for August. Precipitation is expected on 6 days (about 2.4 inches), against a normal of 6 days and 1.9 inches. The warmest day looks like 9 August (83.6°), the coolest 23 August (47.6°).
76.4°/60.6°
Average high / low
−1.9°
Below normal
6 / 6
Wet days / normal
2.4 in
Precipitation this month
Ten-day blocks vs climate normal
Period
Forecast high
Normal
Difference
8 August – 17 August
77.6°
80°
-1.3°
18 August – 27 August
74.3°
79.9°
-3.1°
28 August – 6 September
at normal
78.3°
—
August records over 66 years
98.1°24 August 2023All-time high
46.4°29 August 1986All-time low
Climate normals and records are computed from the nearest reference point — Elgin (14 mi).
Sun, 0984° / 63°1.34
84 °
Harmony, Sunday, 9 August
Heavy rain. High 84°, low 63°.
Pressure29.91 inHg
Wind9.1 mph SE
Humidity94%
Visibility6.2 mi
Dew point63°
Mon, 1083° / 69°0.08
83 °
Harmony, Monday, 10 August
Rain. High 83°, low 69°.
Pressure29.91 inHg
Wind8 mph SE
Humidity83%
Visibility6.2 mi
Dew point72°
Tue, 1181° / 68°0.51
81 °
Harmony, Tuesday, 11 August
Rain. High 81°, low 68°.
Pressure29.80 inHg
Wind8.2 mph NW
Humidity90%
Visibility6.2 mi
Dew point73°
Wed, 1282° / 63°0.01
82 °
Harmony, Wednesday, 12 August
Light rain. High 82°, low 63°.
Pressure29.88 inHg
Wind3.4 mph W
Humidity77%
Visibility6.2 mi
Dew point68°
Thu, 1368° / 57°0.05
68 °
Harmony, Thursday, 13 August
Light rain. High 68°, low 57°.
Pressure29.97 inHg
Wind11.8 mph NE
Humidity80%
Visibility—
Dew point61°
Fri, 1472° / 54°0
72 °
Harmony, Friday, 14 August
Clear. High 72°, low 54°.
Pressure30.18 inHg
Wind6.3 mph SE
Humidity58%
Visibility—
Dew point53°
Sat, 1572° / 54°0
72 °
Harmony, Saturday, 15 August
Overcast. High 72°, low 54°.
Pressure30.33 inHg
Wind6.6 mph S
Humidity60%
Visibility—
Dew point55°
Sun, 1675° / 56°0
75 °
Harmony, Sunday, 16 August
Mostly clear. High 75°, low 56°.
Pressure30.18 inHg
Wind11.5 mph S
Humidity66%
Visibility—
Dew point59°
Mon, 1778° / 64°0.01
78 °
Harmony, Monday, 17 August
Light rain. High 78°, low 64°.
Pressure30.00 inHg
Wind8.2 mph S
Humidity87%
Visibility—
Dew point66°
Tue, 1881° / 65°0
81 °
Harmony, Tuesday, 18 August
Overcast. High 81°, low 65°.
Pressure30.03 inHg
Wind8.8 mph NE
Humidity65%
Visibility—
Dew point65°
Wed, 1979° / 64°0.31
79 °
Harmony, Wednesday, 19 August
Rain. High 79°, low 64°.
Pressure29.91 inHg
Wind9.5 mph SW
Humidity79%
Visibility—
Dew point69°
Thu, 2076° / 63°0.01
76 °
Harmony, Thursday, 20 August
Light rain. High 76°, low 63°.
Pressure29.91 inHg
Wind10.5 mph NE
Humidity73%
Visibility—
Dew point64°
Fri, 2177° / 59°0.04
77 °
Harmony, Friday, 21 August
Light rain. High 77°, low 59°.
Pressure29.97 inHg
Wind7.8 mph SE
Humidity66%
Visibility—
Dew point62°
Sat, 2268° / 54°0.03
68 °
Harmony, Saturday, 22 August
Light rain. High 68°, low 54°.
Pressure30.00 inHg
Wind16.2 mph NE
Humidity89%
Visibility—
Dew point60°
Sun, 2366° / 48°0
66 °
Harmony, Sunday, 23 August
Clear. High 66°, low 48°.
Pressure30.24 inHg
Wind11.2 mph E
Humidity55%
Visibility—
Dew point47°
From day 17 onward the outlook is built from 60-year climate statistics
Mon, 2480° / 64°0.13
80 °
Harmony, Monday, 24 August
Climate normal for this date — 60-year average.
Average high80°
Average low64°
Average precipitation0.13 in
Chance of precipitation25%
Record high98° (2023)
Record low54° (1966)
Tue, 2580° / 64°0.08
80 °
Harmony, Tuesday, 25 August
Climate normal for this date — 60-year average.
Average high80°
Average low64°
Average precipitation0.08 in
Chance of precipitation25%
Record high92° (2003)
Record low53° (2025)
Wed, 2680° / 65°0.16
80 °
Harmony, Wednesday, 26 August
Climate normal for this date — 60-year average.
Average high80°
Average low65°
Average precipitation0.16 in
Chance of precipitation33%
Record high95° (2024)
Record low51° (2025)
Thu, 2780° / 65°0.11
80 °
Harmony, Thursday, 27 August
Climate normal for this date — 60-year average.
Average high80°
Average low65°
Average precipitation0.11 in
Chance of precipitation28%
Record high96° (2024)
Record low53° (2025)
Fri, 2880° / 65°0.13
80 °
Harmony, Friday, 28 August
Climate normal for this date — 60-year average.
Average high80°
Average low65°
Average precipitation0.13 in
Chance of precipitation38%
Record high93° (1984)
Record low47° (1986)
Sat, 2980° / 64°0.13
80 °
Harmony, Saturday, 29 August
Climate normal for this date — 60-year average.
Average high80°
Average low64°
Average precipitation0.13 in
Chance of precipitation28%
Record high94° (1984)
Record low46° (1986)
Sun, 3079° / 63°0.11
79 °
Harmony, Sunday, 30 August
Climate normal for this date — 60-year average.
Average high79°
Average low63°
Average precipitation0.11 in
Chance of precipitation28%
Record high94° (2013)
Record low52° (1986)
Mon, 3179° / 63°0.09
79 °
Harmony, Monday, 31 August
Climate normal for this date — 60-year average.
Average high79°
Average low63°
Average precipitation0.09 in
Chance of precipitation20%
Record high90° (2012)
Record low51° (2009)
Tue, 0178° / 63°0.12
78 °
Harmony, Tuesday, 1 September
Climate normal for this date — 60-year average.
Average high78°
Average low63°
Average precipitation0.12 in
Chance of precipitation32%
Record high93° (2011)
Record low49° (2009)
Wed, 0278° / 63°0.04
78 °
Harmony, Wednesday, 2 September
Climate normal for this date — 60-year average.
Average high78°
Average low63°
Average precipitation0.04 in
Chance of precipitation23%
Record high92° (2008)
Record low49° (1967)
Thu, 0378° / 63°0.09
78 °
Harmony, Thursday, 3 September
Climate normal for this date — 60-year average.
Average high78°
Average low63°
Average precipitation0.09 in
Chance of precipitation27%
Record high93° (2023)
Record low47° (1974)
Fri, 0477° / 62°0.1
77 °
Harmony, Friday, 4 September
Climate normal for this date — 60-year average.
Average high77°
Average low62°
Average precipitation0.1 in
Chance of precipitation32%
Record high92° (2023)
Record low47° (1974)
Sat, 0577° / 61°0.07
77 °
Harmony, Saturday, 5 September
Climate normal for this date — 60-year average.
Average high77°
Average low61°
Average precipitation0.07 in
Chance of precipitation20%
Record high89° (2023)
Record low50° (1962)
Sun, 0677° / 61°0.12
77 °
Harmony, Sunday, 6 September
Climate normal for this date — 60-year average.
Average high77°
Average low61°
Average precipitation0.12 in
Chance of precipitation35%
Record high91° (1990)
Record low48° (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 Harmony, 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 Harmony, 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.