Rockford, IL

Illinois · Records since 1893–2026

☀️ 76°F
Currently in Rockford
As of 1:15 PM CDT

Records for September 11

🔥 Record High

96°F

September 11, 1931

+19° from 77° normal

❄ Record Low

34°F

September 11, 1917

-21° from 55° normal
🌞 Normal high: 77°F 🌑 Normal low: 55°F 1991–2020 normals

All-Time Records — Rockford

🔥
112°F
Hottest Day Ever
Jul 14, 1936
❄
-31°F
Coldest Day Ever
Jan 31, 2019
🌧
5.70"
Wettest Day Ever
Aug 14, 1987
☃
13.5"
Most Snow in One Day
Mar 31, 1926

First & Last Dates — Rockford

How early and how late each seasonal turning point has ever arrived, across the full period of record

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Range ever recorded Normal date (1991–2020)
204 days
Longest growing season
2017
121 days
Shortest growing season
1929
168 days
Normal growing season
1991–2020 average

Top 10 Record Highs — September 11

# Temp Date
🏆 96°F September 11, 1931
2 94°F September 11, 1895
3 92°F September 11, 1920
4 91°F September 11, 2005
5 91°F September 11, 1952
6 90°F September 11, 1978
7 90°F September 11, 1927
8 90°F September 11, 1908
9 89°F September 11, 2021
10 89°F September 11, 1930

Top 5 Record Lows — September 11

# Temp Date
🥶 34°F September 11, 1917
2 38°F September 11, 1940
3 39°F September 11, 1943
4 40°F September 11, 1993
5 41°F September 11, 1955
About this data — Records are sourced from the NOAA Threadex dataset via RCC ACIS, a quality-controlled record for long-term climate stations. Threadex adjusts for station relocations and observation-time changes, making records comparable across all years since 1893–2026. Climate normals represent the 1991–2020 average.

Heat Wave Summary — Rockford

threshold: 92°F (90th percentile of historical Jun–Aug highs)
4.4
Avg heat wave length
days (historical)
98°
Avg peak temp
during heat waves
17
Dangerous nights 2026
Overnights ≥ 70°F
0
Heat waves 2026
so far

Days ≥ 90°F Per Year

1893–2026
17
2026 so far
20
Avg/year 1970–2025
19
Avg/year (last 10 complete)
62
Most in a year (1921)

Average Daily High by Decade

Full year · complete decades only

Longest Heat Waves — Rockford

# Dates Days Peak Avg High Avg Overnight Low
🏆 Jul 6, 1936 – Jul 18, 1936 13 112°F (Jul 14) 104°F 70°F
2 Jul 22, 1916 – Aug 1, 1916 11 105°F (Jul 31) 98°F 69°F
3 Jul 26, 1955 – Aug 4, 1955 10 103°F (Jul 27) 97°F 72°F
4 Aug 25, 1953 – Sep 3, 1953 10 102°F (Sep 1) 98°F 66°F
5 Jun 28, 1921 – Jul 7, 1921 10 100°F (Jul 4) 97°F 69°F
6 Jul 13, 1932 – Jul 22, 1932 10 100°F (Jul 15) 97°F 67°F
7 Jul 23, 1941 – Jul 31, 1941 9 102°F (Jul 29) 96°F 71°F
8 Jun 16, 1921 – Jun 24, 1921 9 95°F (Jun 18) 93°F 67°F
9 Jul 19, 1934 – Jul 26, 1934 8 107°F (Jul 24) 102°F 72°F
10 May 29, 1934 – Jun 5, 1934 8 106°F (May 31) 99°F 64°F

Heat Waves Per Year

Warm Summer Nights (Jun–Aug)

Nights where the overnight low exceeded the 1991–2020 normal low

39
2026 total
above-normal nights
39.5
Avg / summer
1970–2020
65
Most in a summer
1983

Above-Normal Summer Nights Per Year

Average June–August Low by Decade

Overnight lows · complete decades only

Precipitation

Annual totals and trend across the full period of record · see this year's standing →

Monthly Precipitation — Last 24 Months

Blue = actual · dashed line = monthly normal

Annual Precipitation Per Year (1893–2026)

Blue = above average · tan = below average · gold = 2026 (partial)
Since 1893, annual totals have trended +0.57" per decade, about +7.6" across the record.

Heavy Rain Days Per Year (≥ 1.0")

Compare year-to-year changes in days with heavy rainfall (≥ 1.0")

This Year — 2026

How Rockford is tracking against normal, year to date

Daily High Temperature vs Normal

Above normal Below normal

140 of 253 days with data were above the 1991–2020 normal high for their date.

Precipitation, Year to Date

22.50"
2026 YTD
Normal: 28.11"
-5.61"
0.27"
September so far
September normal: 3.62"
-3.35"
6
2026 heavy rain days
Days with ≥ 1.0"

Accumulation vs. Normal

Running total since Jan 1 against the normal pace for the same date · Rockford is 5.61" behind the normal pace

Period Review — Sep 3 – Sep 10, 2026

Any window, evaluated against every other year on record — 8 days

Quick picks: Last 7 days Last 30 days Last 90 days This month
Seasons: Spring (Mar–May) Summer (Jun–Aug) Fall (Sep–Nov)
75.0°F
Average temperature
17th-warmest of 127
+7.3°
vs. average
Normal: 67.7°F (1991–2020)
0.26"
Precipitation
46th-driest of 126
-0.76"
vs. average
Normal: 1.02" · 25% of normal

Average Temperature by Year — Sep 3 – Sep 10

1893–2026 · 2026 highlighted · trend -0.14° per decade (cooling since 1893)

Precipitation by Year — Sep 3 – Sep 10

1895–2026 · 2026 highlighted · trend -0.02" per decade (drier since 1895)

Warmest Sep 3 – Sep 10 on Record

# Year Avg Temp
1 1897 79.9°F
2 1933 79.4°F
3 1922 78.8°F
4 1971 78.6°F
5 1925 78.4°F
6 1947 78.0°F
7 1912 77.7°F
8 1895 77.5°F
9 1961 76.3°F
10 1985 76.3°F

Coolest Sep 3 – Sep 10 on Record

# Year Avg Temp
1 2025 57.4°F
2 1924 58.1°F
3 1907 59.5°F
4 1935 59.9°F
5 1909 60.3°F
6 1962 60.9°F
7 2017 61.2°F
8 1986 61.3°F
9 1993 61.4°F
10 1918 61.4°F

Wettest Sep 3 – Sep 10 on Record

# Year Total
1 1941 6.85"
2 2020 5.25"
3 1938 4.51"
4 2001 4.14"
5 1965 3.34"
6 1916 3.33"
7 2008 2.99"
8 1980 2.76"
9 1973 2.66"
10 1903 2.51"

Driest Sep 3 – Sep 10 on Record

# Year Total
1 2024 0.00"
2 2022 0.00"
3 2017 0.00"
4 2005 0.00"
5 2004 0.00"
6 2003 0.00"
7 1990 0.00"
8 1979 0.00"
9 1978 0.00"
10 1974 0.00"
About this data. Pick any start and end date and this becomes the same kind of review as the Month and Fall tabs, just for exactly the window you asked for — the generalized version of the same engine, evaluated across every year on record. Average temperature is the mean of each day's (high + low) / 2; precipitation is the sum of daily totals. A year missing more than about a fifth of the window's days is excluded from the temperature ranking; any missing day excludes a year from the precipitation ranking, since an unreported day is unreported rain. Ranges that cross from December into January aren't supported yet. Normals are the 1991–2020 mean for the same window.
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