Fort Dearborn Threshold Days by Year (USW00014881)

16 fixed thresholds counted per year at Fort Dearborn (USW00014881): hot days, frost, tropical nights and heavy rain, with the most days in a year.

Key Facts for Fort Dearborn Thresholds

Fort Dearborn: days with a maximum temperature at or above 30 C (86 F) in 40 years, most in 1955 with 48.
Fort Dearborn: days with a maximum temperature at or above 90 F (32.2 C) in 40 years, most in 1955 with 27.
Fort Dearborn: days with a maximum temperature at or below 0 C (32 F) in 40 years, most in 1904 with 77.
Fort Dearborn: nights with a minimum temperature at or below 0 C (32 F) in 40 years, most in 1904 with 132.
16 fixed thresholds have at least one qualifying day at Fort Dearborn.

Days at or above 30 C (86 F)

40 years with a qualifying day

Days per year at Fort Dearborn with a maximum temperature at or above 30 C (86 F), with the decade average as a line. The most was 48 in 1955.

Days at or above 30 C (86 F) per year at Fort Dearborn
Year	Days	Decade average
1901	30	20.2
1902	12	20.2
1903	14	20.2
1904	13	20.2
1905	21	20.2
1906	24	20.2
1907	18	20.2
1908	31	20.2
1909	19	20.2
1910	28	27.2
1911	38	27.2
1912	26	27.2
1913	34	27.2
1914	36	27.2
1915	12	27.2
1916	37	27.2
1917	15	27.2
1918	24	27.2
1919	22	27.2
1920	30	28.8
1921	42	28.8
1922	28	28.8
1923	24	28.8
1924	16	28.8
1925	33	28.8
1949	31	31
1950	19	33.1
1951	18	33.1
1952	41	33.1
1953	40	33.1
1954	40	33.1
1955	48	33.1
1956	32	33.1
1957	23	33.1
1958	23	33.1
1959	47	33.1
1960	29	30
1961	36	30
1962	29	30
1963	26	30

For each year, a bar from the first to the last day at Fort Dearborn meeting 30 C (86 F).

First to last qualifying date each year at Fort Dearborn
Year	First date	Last date
1901	1901-05-02	1901-09-05
1902	1902-05-18	1902-08-02
1903	1903-06-29	1903-09-07
1904	1904-05-25	1904-09-10
1905	1905-06-04	1905-09-22
1906	1906-05-15	1906-09-17
1907	1907-06-16	1907-09-19
1908	1908-05-25	1908-09-26
1909	1909-05-05	1909-09-14
1910	1910-04-29	1910-08-24
1911	1911-05-10	1911-09-02
1912	1912-05-22	1912-09-10
1913	1913-06-06	1913-09-07
1914	1914-05-24	1914-09-21
1915	1915-04-24	1915-09-14
1916	1916-05-26	1916-10-07
1917	1917-05-17	1917-09-01
1918	1918-05-25	1918-08-25
1919	1919-06-14	1919-09-08
1920	1920-06-09	1920-09-26
1921	1921-05-20	1921-09-29
1922	1922-06-06	1922-10-05
1923	1923-06-01	1923-08-18
1924	1924-06-19	1924-09-21
1925	1925-04-23	1925-09-19
1949	1949-05-03	1949-08-27
1950	1950-05-24	1950-08-17
1951	1951-05-16	1951-10-04
1952	1952-05-04	1952-09-28
1953	1953-05-25	1953-09-29
1954	1954-05-31	1954-10-03
1955	1955-05-03	1955-09-19
1956	1956-05-12	1956-09-22
1957	1957-06-16	1957-09-01
1958	1958-05-17	1958-09-09
1959	1959-05-02	1959-09-22
1960	1960-04-23	1960-09-24
1961	1961-05-14	1961-09-22
1962	1962-04-26	1962-09-13
1963	1963-05-08	1963-10-06

Every Fixed Threshold

Fixed thresholds at Fort Dearborn
Threshold	Years with a qualifying day	Most days in a year	Year	Latest year days
30 C (86 F): Days	40	48	1955	26
35 C (95 F): Days	28	14	1953	2
90 F (32.2 C): Days	40	27	1955	11
100 F (37.8 C): Days	7	3	1911	1
0 C (32 F): Ice days (max	40	77	1904	62
0 C (32 F): Frost days (min	40	132	1904	106
-10 C (14 F): Days with min	40	54	1963	54
-20 C (-4 F): Days with min	26	13	1924	9
20 C (68 F): Tropical nights (min	40	73	1921	43
25 C (77 F): Days with min	28	16	1955	1
10 mm (0.39 in): Days with 10 mm or more rain	39	41	1909	18
25 mm (0.98 in): Days with 25 mm or more rain	39	11	1951	3
50 mm (1.97 in): Days with 50 mm or more rain	22	4	1959	1
100 mm (3.94 in): Days with 100 mm or more rain	2	1	1950	1
10 cm (3.9 in): Days with 10 cm or more snowfall	14	7	1918	1
25 cm (9.8 in): Days with 25 cm or more snowfall	3	1	1901	1

Years with under 90 percent of days observed are left out of the most days column. Threshold history at this station starts in 1901.

Download the Data

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 2026-10-17 (17 October 2026). Threshold counts are computed by this site.

Data as of 2025-12-31. Last revised 31 December 2025 (2025-12-31).

Fort Dearborn Threshold Days by Year (USW00014881)

Key Facts for Fort Dearborn Thresholds

Days at or above 30 C (86 F)

Every Fixed Threshold

Download the Data

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