Black Rock Threshold Days by Year (USC00291018)

15 fixed thresholds counted per year at Black Rock (USC00291018): hot days, frost, tropical nights and heavy rain, with the most days in a year.

Key Facts for Black Rock Thresholds

Black Rock: days with 10 mm (0.39 in) or more of precipitation in 35 years, most in 1916 with 14.
Black Rock: days with a maximum temperature at or above 30 C (86 F) in 32 years, most in 1945 with 76.
Black Rock: nights with a minimum temperature at or below 0 C (32 F) in 32 years, most in 1919 with 214.
Black Rock: nights with a minimum temperature at or below -10 C (14 F) in 32 years, most in 1919 with 97.
15 fixed thresholds have at least one qualifying day at Black Rock.

Days at or above 30 C (86 F)

32 years with a qualifying day

Days per year at Black Rock with a maximum temperature at or above 30 C (86 F), with the decade average as a line. The most was 76 in 1945.

Days at or above 30 C (86 F) per year at Black Rock
Year	Days	Decade average
1909	47	47
1910	68	49.7
1912	21	49.7
1915	28	49.7
1916	33	49.7
1917	74	49.7
1918	52	49.7
1919	72	49.7
1921	32	47.9
1922	60	47.9
1923	35	47.9
1924	71	47.9
1925	38	47.9
1926	56	47.9
1927	47	47.9
1928	55	47.9
1929	37	47.9
1930	61	50.6
1931	63	50.6
1932	56	50.6
1933	44	50.6
1934	23	50.6
1935	52	50.6
1936	54	50.6
1937	47	50.6
1938	47	50.6
1939	59	50.6
1940	37	44.2
1941	9	44.2
1942	34	44.2
1944	65	44.2
1945	76	44.2

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

First to last qualifying date each year at Black Rock
Year	First date	Last date
1909	1909-06-03	1909-08-26
1910	1910-05-28	1910-10-08
1912	1912-05-29	1912-08-08
1915	1915-06-21	1915-08-21
1916	1916-06-08	1916-08-11
1917	1917-06-09	1917-10-02
1918	1918-06-06	1918-09-21
1919	1919-06-08	1919-09-12
1921	1921-06-08	1921-09-27
1922	1922-05-29	1922-08-31
1923	1923-06-11	1923-08-05
1924	1924-06-03	1924-09-08
1925	1925-05-18	1925-08-30
1926	1926-06-09	1926-09-20
1927	1927-06-06	1927-09-04
1928	1928-05-29	1928-09-15
1929	1929-06-14	1929-09-15
1930	1930-06-05	1930-09-19
1931	1931-06-01	1931-09-27
1932	1932-06-12	1932-09-17
1933	1933-05-29	1933-09-28
1934	1934-06-11	1934-08-02
1935	1935-06-08	1935-09-18
1936	1936-06-09	1936-08-27
1937	1937-06-11	1937-09-13
1938	1938-05-17	1938-09-27
1939	1939-06-03	1939-09-05
1940	1940-06-14	1940-08-14
1941	1941-06-17	1941-08-06
1942	1942-06-16	1942-09-03
1944	1944-06-06	1944-09-23
1945	1945-06-13	1945-09-16

Every Fixed Threshold

Fixed thresholds at Black Rock
Threshold	Years with a qualifying day	Most days in a year	Year	Latest year days
30 C (86 F): Days	32	76	1945	76
35 C (95 F): Days	24	17	1919	2
90 F (32.2 C): Days	31	41	1919	30
100 F (37.8 C): Days	2	5	1919	5
0 C (32 F): Ice days (max	29	25	1918	4
0 C (32 F): Frost days (min	32	214	1919	197
-10 C (14 F): Days with min	32	97	1919	38
-20 C (-4 F): Days with min	23	18	1919	4
-30 C (-22 F): Days with min	3	3	1919	1
20 C (68 F): Tropical nights (min	4	8	1912	1
10 mm (0.39 in): Days with 10 mm or more rain	35	14	1916	5
25 mm (0.98 in): Days with 25 mm or more rain	16	3	1919	1
50 mm (1.97 in): Days with 50 mm or more rain	1	1	1932	1
10 cm (3.9 in): Days with 10 cm or more snowfall	24	4	1919	1
25 cm (9.8 in): Days with 25 cm or more snowfall	2	1	1931	1

Years with under 90 percent of days observed are left out of the most days column. Threshold history at this station starts in 1909.

Download the Data

Data for Black Rock 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).

Black Rock Threshold Days by Year (USC00291018)

Key Facts for Black Rock Thresholds

Days at or above 30 C (86 F)

Every Fixed Threshold

Download the Data

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