Record envelope, standing records and threshold days for Fort Dearborn (USW00014881), Illinois, United States, with 130 years of record.
Key Facts for Fort Dearborn
Fort Dearborn (USW00014881) is a weather station in Illinois, United States at 41.89 latitude and -87.63 longitude, 183 m (600 ft) above sea level.
The station reports from 1836 to 1965, 130 years of record.
1,464 records set at Fort Dearborn still stand.
Records are tracked for tmax, tmin, prcp: an element needs 30 years of data to be eligible.
Fort Dearborn set a daily record high maximum temperature of 14.4 C (57.9 F) on 28 February 1965.
About the Station
Location: Illinois, United States, 41.89 latitude, -87.63 longitude.
Elevation: 183 m (600 ft).
Period of record: 1836 to 1965, 130 years.
Eligible elements: tmax, tmin, prcp.
Daily Record Envelope and 2026
0 days at or beyond a record
Record highRecord low2026 daily maximum2026 daily minimum
The band shows the record high and record low for each calendar day at Fort Dearborn. The lines show the 2026 daily maximum and minimum. 0 days in 2026 matched or passed a record. Temperatures are in degrees Celsius.
Daily record high and record low at Fort Dearborn, with 2026 drawn through them
Month
Highest record high
Lowest record low
2026 highest maximum
2026 lowest minimum
Jan
19.4 C (66.9 F)
-26.7 C (-16.1 F)
n/a
n/a
Feb
20.0 C (68.0 F)
-27.8 C (-18.0 F)
n/a
n/a
Mar
27.2 C (81.0 F)
-20.0 C (-4.0 F)
n/a
n/a
Apr
31.1 C (88.0 F)
-6.7 C (19.9 F)
n/a
n/a
May
34.4 C (93.9 F)
-0.6 C (30.9 F)
n/a
n/a
Jun
39.4 C (102.9 F)
6.1 C (43.0 F)
n/a
n/a
Jul
39.4 C (102.9 F)
10.0 C (50.0 F)
n/a
n/a
Aug
38.9 C (102.0 F)
8.3 C (46.9 F)
n/a
n/a
Sep
37.2 C (99.0 F)
2.2 C (36.0 F)
n/a
n/a
Oct
32.2 C (90.0 F)
-7.2 C (19.0 F)
n/a
n/a
Nov
26.1 C (79.0 F)
-17.8 C (0.0 F)
n/a
n/a
Dec
18.9 C (66.0 F)
-25.0 C (-13.0 F)
n/a
n/a
Which Years Hold Standing Records
1,464 standing records
Year with most
1,464 records at Fort Dearborn still stand. 1916 holds the most, with 48.
Standing records at Fort Dearborn by the year they were set
Year set
Standing records
1901
45
1902
41
1903
47
1904
37
1905
36
1906
29
1907
38
1908
34
1909
39
1910
38
1911
40
1912
36
1913
47
1914
37
1915
43
1916
48
1917
36
1918
34
1919
26
1920
42
1921
37
1922
28
1923
34
1924
35
1925
46
1948
18
1949
34
1950
43
1951
34
1952
32
1953
34
1954
22
1955
45
1956
32
1957
23
1958
17
1959
26
1960
23
1961
11
1962
44
1963
32
1964
32
1965
9
All-Time Record Progression
1 new records
1 all-time records were set at Fort Dearborn between 12 July 1957 and 12 July 1957. Each dot is a new record.
When Fort Dearborn set new all-time records
Date
Kind
Detail
1957-07-12
Record daily precipitation
Record daily precipitation 147.3 mm (5.8 in)
Wettest Day of Each Month
Jul: 147.3 mm (5.8 in)
The wettest day on record for each calendar month at Fort Dearborn. The most was 147.3 mm (5.8 in) on 12 July 1957.
Record daily precipitation for each month at Fort Dearborn
Month
Record daily precipitation (mm)
Date
Jan
80.0 mm (3.1 in)
12 January 1960
Feb
34.8 mm (1.4 in)
13 February 1950
Mar
44.2 mm (1.7 in)
26 March 1959
Apr
71.9 mm (2.8 in)
27 April 1959
May
81.3 mm (3.2 in)
10 May 1951
Jun
103.9 mm (4.1 in)
2 June 1950
Jul
147.3 mm (5.8 in)
12 July 1957
Aug
94.0 mm (3.7 in)
11 August 1923
Sep
64.3 mm (2.5 in)
13 September 1961
Oct
95.5 mm (3.8 in)
10 October 1954
Nov
51.3 mm (2.0 in)
4 November 1959
Dec
44.2 mm (1.7 in)
21 December 1949
Period of Record Coverage
1901 to 1965
Complete yearUnder 90 percent of days
43 years of record at Fort Dearborn, 1901 to 1965. 3 years have data for under 90 percent of days and are left out of rankings: 1948, 1964, 1965.
Cooler than the station meanWarmer than the station mean
One stripe for each of 40 complete years at Fort Dearborn, 1901 to 1963. Blue stripes are years cooler than the station's own mean of 10.3 C (50.5 F); red stripes are warmer. The coolest year was 1904, at 8.1 C (46.5 F), and the warmest was 1921, at 12.5 C (54.4 F). The strongest colour marks a difference of 2.3 C (4.1 F).
Annual mean temperature at Fort Dearborn as warming stripes, 1901 to 1963
Year
Annual mean temperature
Difference from the station mean
1901
8.9 C
-1.41 C
1902
9.2 C
-1.06 C
1903
8.7 C
-1.61 C
1904
8.1 C
-2.23 C
1905
9.1 C
-1.20 C
1906
10.6 C
+0.33 C
1907
9.5 C
-0.75 C
1908
10.9 C
+0.65 C
1909
9.8 C
-0.44 C
1910
10.3 C
+0.06 C
1911
11.1 C
+0.82 C
1912
9.1 C
-1.18 C
1913
10.9 C
+0.59 C
1914
10.6 C
+0.32 C
1915
10.1 C
-0.22 C
1916
10.1 C
-0.17 C
1917
8.2 C
-2.10 C
1918
10.1 C
-0.15 C
1919
10.6 C
+0.33 C
1920
9.9 C
-0.34 C
1921
12.5 C
+2.18 C
1922
11.2 C
+0.87 C
1923
10.2 C
-0.08 C
1924
8.9 C
-1.34 C
1925
10.2 C
-0.13 C
1949
11.5 C
+1.25 C
1950
9.8 C
-0.51 C
1951
9.6 C
-0.69 C
1952
11.4 C
+1.10 C
1953
11.9 C
+1.64 C
1954
11.6 C
+1.36 C
1955
11.4 C
+1.13 C
1956
11.3 C
+0.99 C
1957
10.7 C
+0.45 C
1958
10.3 C
-0.03 C
1959
11.0 C
+0.68 C
1960
10.6 C
+0.30 C
1961
10.8 C
+0.53 C
1962
10.3 C
+0.04 C
1963
10.2 C
-0.07 C
The annual mean temperature here has risen by 0.2 C (0.1 to 0.4) per decade over 1901 to 1963. In Fahrenheit: 0.4 F (0.2 to 0.6) per decade. The slope is a straight line fitted to 40 complete years; the brackets give its 95 percent interval.
Fitted temperature trends per decade at Fort Dearborn
Measure
Per decade (C)
Per decade (F)
Period
Complete years
Reading
Annual mean temperature
0.2 C (0.1 to 0.4) per decade
0.4 F (0.2 to 0.6) per decade
1901 to 1963
40
Rise
Mean daily maximum
0.2 C (0.1 to 0.3) per decade
0.4 F (0.1 to 0.6) per decade
1901 to 1963
40
Rise
Mean daily minimum
0.2 C (0.1 to 0.4) per decade
0.4 F (0.2 to 0.7) per decade
1901 to 1963
40
Rise
A year is complete when all 12 months have at least 20 days of both daily maximum and daily minimum readings. The annual mean is the mean of the monthly means. The trend describes this one station over this period; it does not say what caused the change.
Extremes by Year
1836 to 1965
Yearly extremes at Fort Dearborn: the record and the median year
Measure
Record
Year of the record
Median year
Years with a value
Hottest day (TXx)
39.4 C (102.9 F)
1901
36.1 C (97.0 F)
43
Coldest night (TNn)
-27.8 C (-18.0 F)
1905
-21.1 C (-6.0 F)
43
Wettest day (Rx1day)
147.3 mm (5.8 in)
1957
55.8 mm (2.2 in)
44
Wettest five days (Rx5day)
170.6 mm (6.7 in)
1954
80.4 mm (3.2 in)
44
Longest dry spell (CDD)
38 days
1920
22 days
44
Hottest day (TXx)
The hottest day of the year at Fort Dearborn, 1836 to 1965. The record is 39.4 C (102.9 F) in 1901, marked on the chart; the median year is 36.1 C (97.0 F).
Hottest day (TXx) at Fort Dearborn by year
Year
Hottest day (TXx)
1836
n/a
1901
39.4 C (102.9 F)
1902
32.8 C (91.0 F)
1903
33.3 C (91.9 F)
1904
34.4 C (93.9 F)
1905
35.0 C (95.0 F)
1906
33.9 C (93.0 F)
1907
33.3 C (91.9 F)
1908
35.6 C (96.1 F)
1909
33.9 C (93.0 F)
1910
36.1 C (97.0 F)
1911
38.9 C (102.0 F)
1912
35.0 C (95.0 F)
1913
37.2 C (99.0 F)
1914
37.2 C (99.0 F)
1915
32.2 C (90.0 F)
1916
38.9 C (102.0 F)
1917
36.7 C (98.1 F)
1918
38.9 C (102.0 F)
1919
36.7 C (98.1 F)
1920
36.7 C (98.1 F)
1921
36.1 C (97.0 F)
1922
36.7 C (98.1 F)
1923
35.6 C (96.1 F)
1924
34.4 C (93.9 F)
1925
36.7 C (98.1 F)
1948
36.7 C (98.1 F)
1949
37.2 C (99.0 F)
1950
33.3 C (91.9 F)
1951
33.3 C (91.9 F)
1952
37.2 C (99.0 F)
1953
39.4 C (102.9 F)
1954
37.2 C (99.0 F)
1955
38.3 C (100.9 F)
1956
37.8 C (100.0 F)
1957
35.0 C (95.0 F)
1958
33.9 C (93.0 F)
1959
35.0 C (95.0 F)
1960
36.1 C (97.0 F)
1961
34.4 C (93.9 F)
1962
36.7 C (98.1 F)
1963
36.1 C (97.0 F)
1964
36.7 C (98.1 F)
1965
15.6 C (60.1 F)
Coldest night (TNn)
The coldest night of the year at Fort Dearborn, 1836 to 1965. The record is -27.8 C (-18.0 F) in 1905, marked on the chart; the median year is -21.1 C (-6.0 F).
Coldest night (TNn) at Fort Dearborn by year
Year
Coldest night (TNn)
1836
n/a
1901
-24.4 C (-11.9 F)
1902
-22.2 C (-8.0 F)
1903
-25.0 C (-13.0 F)
1904
-26.1 C (-15.0 F)
1905
-27.8 C (-18.0 F)
1906
-14.4 C (6.1 F)
1907
-19.4 C (-2.9 F)
1908
-18.9 C (-2.0 F)
1909
-23.3 C (-9.9 F)
1910
-21.1 C (-6.0 F)
1911
-17.8 C (0.0 F)
1912
-26.7 C (-16.1 F)
1913
-20.0 C (-4.0 F)
1914
-21.1 C (-6.0 F)
1915
-20.6 C (-5.1 F)
1916
-21.1 C (-6.0 F)
1917
-23.3 C (-9.9 F)
1918
-25.6 C (-14.1 F)
1919
-23.9 C (-11.0 F)
1920
-21.7 C (-7.1 F)
1921
-13.3 C (8.1 F)
1922
-19.4 C (-2.9 F)
1923
-22.2 C (-8.0 F)
1924
-26.7 C (-16.1 F)
1925
-22.2 C (-8.0 F)
1948
-10.6 C (12.9 F)
1949
-18.9 C (-2.0 F)
1950
-17.8 C (0.0 F)
1951
-24.4 C (-11.9 F)
1952
-17.8 C (0.0 F)
1953
-15.6 C (3.9 F)
1954
-20.6 C (-5.1 F)
1955
-20.6 C (-5.1 F)
1956
-15.0 C (5.0 F)
1957
-19.4 C (-2.9 F)
1958
-20.6 C (-5.1 F)
1959
-19.4 C (-2.9 F)
1960
-21.1 C (-6.0 F)
1961
-17.2 C (1.0 F)
1962
-22.8 C (-9.0 F)
1963
-25.6 C (-14.1 F)
1964
-16.7 C (1.9 F)
1965
-22.8 C (-9.0 F)
Wettest day (Rx1day)
The wettest day of the year at Fort Dearborn, 1836 to 1965. The record is 147.3 mm (5.8 in) in 1957, marked on the chart; the median year is 55.8 mm (2.2 in).
Wettest day (Rx1day) at Fort Dearborn by year
Year
Wettest day (Rx1day)
1836
30.5 mm (1.2 in)
1901
46.0 mm (1.8 in)
1902
49.5 mm (1.9 in)
1903
31.2 mm (1.2 in)
1904
40.9 mm (1.6 in)
1905
70.6 mm (2.8 in)
1906
73.9 mm (2.9 in)
1907
43.7 mm (1.7 in)
1908
58.7 mm (2.3 in)
1909
88.6 mm (3.5 in)
1910
46.0 mm (1.8 in)
1911
37.6 mm (1.5 in)
1912
46.5 mm (1.8 in)
1913
45.2 mm (1.8 in)
1914
41.9 mm (1.6 in)
1915
58.7 mm (2.3 in)
1916
58.2 mm (2.3 in)
1917
32.5 mm (1.3 in)
1918
41.4 mm (1.6 in)
1919
43.4 mm (1.7 in)
1920
57.4 mm (2.3 in)
1921
52.6 mm (2.1 in)
1922
64.3 mm (2.5 in)
1923
94.0 mm (3.7 in)
1924
69.1 mm (2.7 in)
1925
43.2 mm (1.7 in)
1948
49.3 mm (1.9 in)
1949
86.1 mm (3.4 in)
1950
103.9 mm (4.1 in)
1951
81.3 mm (3.2 in)
1952
37.6 mm (1.5 in)
1953
33.8 mm (1.3 in)
1954
95.5 mm (3.8 in)
1955
61.2 mm (2.4 in)
1956
35.8 mm (1.4 in)
1957
147.3 mm (5.8 in)
1958
72.1 mm (2.8 in)
1959
71.9 mm (2.8 in)
1960
80.0 mm (3.1 in)
1961
71.4 mm (2.8 in)
1962
82.3 mm (3.2 in)
1963
77.2 mm (3.0 in)
1964
54.1 mm (2.1 in)
1965
39.6 mm (1.6 in)
Wettest five days (Rx5day)
The wettest five days of the year at Fort Dearborn, 1836 to 1965. The record is 170.6 mm (6.7 in) in 1954, marked on the chart; the median year is 80.4 mm (3.2 in).
Wettest five days (Rx5day) at Fort Dearborn by year
Year
Wettest five days (Rx5day)
1836
47.0 mm (1.9 in)
1901
70.8 mm (2.8 in)
1902
70.9 mm (2.8 in)
1903
63.8 mm (2.5 in)
1904
80.3 mm (3.2 in)
1905
98.1 mm (3.9 in)
1906
81.0 mm (3.2 in)
1907
59.5 mm (2.3 in)
1908
141.5 mm (5.6 in)
1909
121.9 mm (4.8 in)
1910
56.2 mm (2.2 in)
1911
80.5 mm (3.2 in)
1912
73.1 mm (2.9 in)
1913
63.8 mm (2.5 in)
1914
71.2 mm (2.8 in)
1915
66.8 mm (2.6 in)
1916
106.2 mm (4.2 in)
1917
61.2 mm (2.4 in)
1918
68.1 mm (2.7 in)
1919
74.2 mm (2.9 in)
1920
66.0 mm (2.6 in)
1921
75.5 mm (3.0 in)
1922
89.8 mm (3.5 in)
1923
126.3 mm (5.0 in)
1924
151.7 mm (6.0 in)
1925
48.6 mm (1.9 in)
1948
74.7 mm (2.9 in)
1949
103.4 mm (4.1 in)
1950
108.0 mm (4.3 in)
1951
89.9 mm (3.5 in)
1952
64.1 mm (2.5 in)
1953
54.6 mm (2.1 in)
1954
170.6 mm (6.7 in)
1955
103.9 mm (4.1 in)
1956
85.9 mm (3.4 in)
1957
153.4 mm (6.0 in)
1958
85.8 mm (3.4 in)
1959
82.1 mm (3.2 in)
1960
101.3 mm (4.0 in)
1961
145.4 mm (5.7 in)
1962
82.3 mm (3.2 in)
1963
88.1 mm (3.5 in)
1964
60.2 mm (2.4 in)
1965
77.0 mm (3.0 in)
Longest dry spell (CDD)
The longest dry spell of the year at Fort Dearborn, 1836 to 1965. The record is 38 days in 1920, marked on the chart; the median year is 22 days.
Longest dry spell (CDD) at Fort Dearborn by year
Year
Longest dry spell (CDD)
1836
20 days
1901
23 days
1902
19 days
1903
26 days
1904
22 days
1905
21 days
1906
13 days
1907
17 days
1908
24 days
1909
17 days
1910
22 days
1911
22 days
1912
16 days
1913
24 days
1914
22 days
1915
30 days
1916
20 days
1917
22 days
1918
16 days
1919
37 days
1920
38 days
1921
13 days
1922
33 days
1923
20 days
1924
23 days
1925
23 days
1948
19 days
1949
14 days
1950
24 days
1951
16 days
1952
21 days
1953
22 days
1954
17 days
1955
22 days
1956
19 days
1957
29 days
1958
19 days
1959
23 days
1960
21 days
1961
17 days
1962
24 days
1963
19 days
1964
24 days
1965
6 days
Each chart shows one value per year; the dot marks the record year. TXx is the hottest daily maximum, TNn the coldest daily minimum, Rx1day and Rx5day the largest one-day and five-day rain totals, and CDD the longest run of days with less than 1 mm of rain. A year with missing days can understate an extreme.
Frost Dates and Growing Season
40 years with a frost
Across 40 years with a frost, the median last spring frost at Fort Dearborn falls on 12 April and the median first autumn frost on 4 November, which leaves a median of 206 days between them.
Fitted over all years, the growing season changes by +2.4 days per decade at this station.
Frost dates and growing season at Fort Dearborn
Measure
Median, all years
Earliest period
Recent period (1911 to 1963)
Recent against earliest
Fitted trend
Last spring frost
12 April
n/a
11 April
n/a
-0.8 days per decade
First autumn frost
4 November
n/a
4 November
n/a
+1.6 days per decade
Growing days
206 days
n/a
209 days
n/a
+2.4 days per decade
A frost day is a day with a daily minimum at or below 0 C (32 F). The last spring frost and the first autumn frost are the last and first such days of the cold season, and growing days are the days between them. A negative trend for the last spring frost means it comes earlier.
Rainfall Return Levels
39 years, 1901 to 1962
A day with at least 56.4 mm (2.2 in) of rain is expected about once in 2 years. A day with at least 146.4 mm (5.8 in) of rain is expected about once in 100 years.
Rainfall return levels at Fort Dearborn: the daily rain expected about once in a given number of years
Expected about once in
A day with at least
Note
2 years
56.4 mm (2.2 in)
5 years
77.7 mm (3.1 in)
10 years
92.9 mm (3.7 in)
25 years
113.4 mm (4.5 in)
50 years
129.5 mm (5.1 in)
Longer than the 39 years of record
100 years
146.4 mm (5.8 in)
Longer than the 39 years of record
The levels come from a generalised extreme value (GEV) distribution fitted by L-moments to the wettest-day total of each year, 39 years of values from 1901 to 1962.
A return level is an estimate. It is least reliable for the long periods, 50 and 100 years, and for any period longer than the record behind the fit, where the fit has to reach past the largest day actually observed. It is not a forecast.
The largest wettest-day totals in the fit: 147.3 mm (5.8 in) in 1957; 103.9 mm (4.1 in) in 1950; 95.5 mm (3.8 in) in 1954.
Station Changes
No change in the annual mean temperature of this station was found against its neighbours.
Download the Data
Data for Fort Dearborn standing records by year: CSV or JSON. Field meanings are on the data page.
Data for Fort Dearborn threshold days by year: CSV or JSON. Field meanings are on the data page.
Source: NOAA National Centers for Environmental Information, Global Historical Climatology Network Daily (GHCN-Daily). Records are computed by World Extreme Weather Monitor and are not official NOAA products. (US Government open data (NOAA NCEI)) Data as of 2026-10-15 (15 October 2026). Records are computed by this site and are not official.