Monthly outlook for Byron, IL: average high 78.4°, average low 61.8°. That is 0.8° below the climate normal for August. Precipitation is expected on 6 days (about 1.6 inches), against a normal of 5 days and 1.8 inches. The warmest day looks like 11 August (85.6°), the coolest 23 August (44.7°).
78.4°/61.8°
Average high / low
−0.8°
Below normal
6 / 5
Wet days / normal
1.6 in
Precipitation this month
Ten-day blocks vs climate normal
Period
Forecast high
Normal
Difference
8 August – 17 August
79.5°
79.9°
-0.3°
18 August – 27 August
76.7°
79.8°
-1.7°
28 August – 6 September
at normal
78.2°
—
August records over 66 years
98.8°23 August 2023All-time high
44.1°29 August 1965All-time low
Climate normals and records are computed from the nearest reference point — Rockford (14 mi).
Sun, 0985° / 64°0.67
85 °
Byron, Sunday, 9 August
Heavy rain. High 85°, low 64°.
Pressure29.91 inHg
Wind11.1 mph SE
Humidity94%
Visibility6.2 mi
Dew point69°
Mon, 1084° / 70°0.03
84 °
Byron, Monday, 10 August
Light rain. High 84°, low 70°.
Pressure29.88 inHg
Wind10.8 mph S
Humidity69%
Visibility6.2 mi
Dew point73°
Tue, 1186° / 71°0.25
86 °
Byron, Tuesday, 11 August
Rain. High 86°, low 71°.
Pressure29.80 inHg
Wind7.4 mph W
Humidity76%
Visibility6.2 mi
Dew point73°
Wed, 1282° / 65°0.01
82 °
Byron, Wednesday, 12 August
Light rain. High 82°, low 65°.
Pressure29.88 inHg
Wind0.3 mph N
Humidity77%
Visibility6.2 mi
Dew point70°
Thu, 1370° / 60°0.04
70 °
Byron, Thursday, 13 August
Light rain. High 70°, low 60°.
Pressure29.97 inHg
Wind11.9 mph E
Humidity77%
Visibility—
Dew point62°
Fri, 1474° / 55°0
74 °
Byron, Friday, 14 August
Clear. High 74°, low 55°.
Pressure30.21 inHg
Wind6.2 mph E
Humidity59%
Visibility—
Dew point55°
Sat, 1574° / 55°0
74 °
Byron, Saturday, 15 August
Overcast. High 74°, low 55°.
Pressure30.30 inHg
Wind7.9 mph S
Humidity58%
Visibility—
Dew point55°
Sun, 1677° / 57°0
77 °
Byron, Sunday, 16 August
Overcast. High 77°, low 57°.
Pressure30.18 inHg
Wind11.3 mph S
Humidity65%
Visibility—
Dew point60°
Mon, 1781° / 65°0.01
81 °
Byron, Monday, 17 August
Light rain. High 81°, low 65°.
Pressure29.97 inHg
Wind7.6 mph S
Humidity78%
Visibility—
Dew point70°
Tue, 1883° / 67°0.01
83 °
Byron, Tuesday, 18 August
Light rain. High 83°, low 67°.
Pressure30.03 inHg
Wind7.5 mph SE
Humidity63%
Visibility—
Dew point66°
Wed, 1980° / 67°0.32
80 °
Byron, Wednesday, 19 August
Rain. High 80°, low 67°.
Pressure29.91 inHg
Wind10.5 mph S
Humidity80%
Visibility—
Dew point71°
Thu, 2077° / 65°0.03
77 °
Byron, Thursday, 20 August
Light rain. High 77°, low 65°.
Pressure29.91 inHg
Wind10 mph NE
Humidity66%
Visibility—
Dew point64°
Fri, 2180° / 62°0.05
80 °
Byron, Friday, 21 August
Light rain. High 80°, low 62°.
Pressure29.97 inHg
Wind6.5 mph S
Humidity61%
Visibility—
Dew point63°
Sat, 2270° / 55°0.04
70 °
Byron, Saturday, 22 August
Light rain. High 70°, low 55°.
Pressure30.00 inHg
Wind14.8 mph NE
Humidity87%
Visibility—
Dew point61°
Sun, 2369° / 45°0
69 °
Byron, Sunday, 23 August
Clear. High 69°, low 45°.
Pressure30.24 inHg
Wind11 mph E
Humidity51%
Visibility—
Dew point46°
From day 17 onward the outlook is built from 60-year climate statistics
Mon, 2480° / 63°0.1
80 °
Byron, Monday, 24 August
Climate normal for this date — 60-year average.
Average high80°
Average low63°
Average precipitation0.1 in
Chance of precipitation28%
Record high98° (2023)
Record low52° (1984)
Tue, 2580° / 64°0.07
80 °
Byron, Tuesday, 25 August
Climate normal for this date — 60-year average.
Average high80°
Average low64°
Average precipitation0.07 in
Chance of precipitation20%
Record high92° (1991)
Record low51° (2017)
Wed, 2680° / 64°0.16
80 °
Byron, Wednesday, 26 August
Climate normal for this date — 60-year average.
Average high80°
Average low64°
Average precipitation0.16 in
Chance of precipitation30%
Record high94° (2003)
Record low50° (1964)
Thu, 2780° / 65°0.11
80 °
Byron, Thursday, 27 August
Climate normal for this date — 60-year average.
Average high80°
Average low65°
Average precipitation0.11 in
Chance of precipitation27%
Record high95° (2024)
Record low51° (1968)
Fri, 2880° / 64°0.15
80 °
Byron, Friday, 28 August
Climate normal for this date — 60-year average.
Average high80°
Average low64°
Average precipitation0.15 in
Chance of precipitation35%
Record high92° (1984)
Record low46° (1986)
Sat, 2980° / 63°0.13
80 °
Byron, Saturday, 29 August
Climate normal for this date — 60-year average.
Average high80°
Average low63°
Average precipitation0.13 in
Chance of precipitation22%
Record high93° (1984)
Record low44° (1965)
Sun, 3078° / 63°0.06
78 °
Byron, Sunday, 30 August
Climate normal for this date — 60-year average.
Average high78°
Average low63°
Average precipitation0.06 in
Chance of precipitation30%
Record high93° (2013)
Record low53° (2009)
Mon, 3178° / 62°0.07
78 °
Byron, Monday, 31 August
Climate normal for this date — 60-year average.
Average high78°
Average low62°
Average precipitation0.07 in
Chance of precipitation23%
Record high91° (2012)
Record low46° (2009)
Tue, 0178° / 62°0.09
78 °
Byron, Tuesday, 1 September
Climate normal for this date — 60-year average.
Average high78°
Average low62°
Average precipitation0.09 in
Chance of precipitation30%
Record high92° (2011)
Record low46° (1967)
Wed, 0279° / 62°0.05
79 °
Byron, Wednesday, 2 September
Climate normal for this date — 60-year average.
Average high79°
Average low62°
Average precipitation0.05 in
Chance of precipitation25%
Record high92° (2008)
Record low47° (1967)
Thu, 0378° / 62°0.11
78 °
Byron, Thursday, 3 September
Climate normal for this date — 60-year average.
Average high78°
Average low62°
Average precipitation0.11 in
Chance of precipitation35%
Record high94° (2023)
Record low47° (1974)
Fri, 0477° / 61°0.09
77 °
Byron, Friday, 4 September
Climate normal for this date — 60-year average.
Average high77°
Average low61°
Average precipitation0.09 in
Chance of precipitation32%
Record high93° (2023)
Record low45° (1974)
Sat, 0577° / 60°0.06
77 °
Byron, Saturday, 5 September
Climate normal for this date — 60-year average.
Average high77°
Average low60°
Average precipitation0.06 in
Chance of precipitation25%
Record high89° (2023)
Record low48° (1974)
Sun, 0677° / 61°0.1
77 °
Byron, Sunday, 6 September
Climate normal for this date — 60-year average.
Average high77°
Average low61°
Average precipitation0.1 in
Chance of precipitation32%
Record high90° (1990)
Record low46° (1988)
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 Byron, 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 Byron, 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.