Rock Island Threshold Days by Year (USC00457105)

18 fixed thresholds counted per year at Rock Island (USC00457105): hot days, frost, tropical nights and heavy rain, with the most days in a year.

Key Facts for Rock Island Thresholds

Rock Island: days with a maximum temperature at or above 30 C (86 F) in 31 years, most in 1922 with 94.
Rock Island: days with a maximum temperature at or above 35 C (95 F) in 31 years, most in 1938 with 48.
Rock Island: days with a maximum temperature at or above 90 F (32.2 C) in 31 years, most in 1922 with 77.
Rock Island: days with a maximum temperature at or above 100 F (37.8 C) in 31 years, most in 1942 with 23.
18 fixed thresholds have at least one qualifying day at Rock Island.

Days at or above 30 C (86 F)

31 years with a qualifying day

Days per year at Rock Island with a maximum temperature at or above 30 C (86 F), with the decade average as a line. The most was 94 in 1922.

Days at or above 30 C (86 F) per year at Rock Island
Year	Days	Decade average
1914	74	64.5
1915	62	64.5
1916	53	64.5
1917	69	64.5
1920	66	70.2
1921	59	70.2
1922	94	70.2
1923	73	70.2
1924	80	70.2
1925	76	70.2
1926	69	70.2
1927	51	70.2
1928	69	70.2
1929	65	70.2
1930	63	73.9
1931	71	73.9
1932	72	73.9
1933	60	73.9
1934	88	73.9
1935	71	73.9
1936	79	73.9
1937	66	73.9
1938	92	73.9
1939	77	73.9
1940	91	72.3
1941	60	72.3
1942	71	72.3
1943	69	72.3
1944	71	72.3
1945	78	72.3
1946	66	72.3

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

First to last qualifying date each year at Rock Island
Year	First date	Last date
1914	1914-05-30	1914-09-06
1915	1915-05-07	1915-09-18
1916	1916-05-01	1916-09-22
1917	1917-06-13	1917-10-03
1920	1920-05-07	1920-09-30
1921	1921-05-24	1921-08-30
1922	1922-05-15	1922-09-25
1923	1923-05-07	1923-09-14
1924	1924-05-09	1924-09-16
1925	1925-05-05	1925-09-23
1926	1926-04-14	1926-09-04
1927	1927-05-14	1927-09-21
1928	1928-05-15	1928-09-23
1929	1929-05-19	1929-09-16
1930	1930-05-13	1930-09-17
1931	1931-04-28	1931-09-04
1932	1932-05-12	1932-10-02
1933	1933-06-02	1933-09-04
1934	1934-04-12	1934-09-17
1935	1935-05-20	1935-10-03
1936	1936-04-12	1936-09-21
1937	1937-05-02	1937-09-16
1938	1938-05-21	1938-09-26
1939	1939-04-28	1939-09-26
1940	1940-05-18	1940-09-26
1941	1941-05-23	1941-08-22
1942	1942-06-13	1942-09-27
1943	1943-04-13	1943-10-08
1944	1944-05-14	1944-09-25
1945	1945-05-02	1945-10-12
1946	1946-04-25	1946-09-13

Every Fixed Threshold

Fixed thresholds at Rock Island
Threshold	Years with a qualifying day	Most days in a year	Year	Latest year days
30 C (86 F): Days	31	94	1922	66
35 C (95 F): Days	31	48	1938	23
40 C (104 F): Days	27	7	1938	4
45 C (113 F): Days	1	2	1939	2
90 F (32.2 C): Days	31	77	1922	33
100 F (37.8 C): Days	31	23	1942	10
110 F (43.3 C): Days	6	2	1934	1
0 C (32 F): Ice days (max	31	56	1916	8
0 C (32 F): Frost days (min	31	158	1916	109
-10 C (14 F): Days with min	30	56	1922	3
-20 C (-4 F): Days with min	12	13	1922	2
-30 C (-22 F): Days with min	1	1	1937	1
20 C (68 F): Tropical nights (min	25	34	1923	4
25 C (77 F): Days with min	3	15	1923	1
10 mm (0.39 in): Days with 10 mm or more rain	29	13	1937	5
25 mm (0.98 in): Days with 25 mm or more rain	9	2	1917	1
50 mm (1.97 in): Days with 50 mm or more rain	1	1	1936	1
10 cm (3.9 in): Days with 10 cm or more snowfall	4	3	1922	3

Years with under 90 percent of days observed are left out of the most days column. Threshold history at this station starts in 1914.

Download the Data

Data for Rock Island 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).

Rock Island Threshold Days by Year (USC00457105)

Key Facts for Rock Island Thresholds

Days at or above 30 C (86 F)

Every Fixed Threshold

Download the Data

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