Mertzon Threshold Days by Year (USC00415859)

15 fixed thresholds counted per year at Mertzon (USC00415859): hot days, frost, tropical nights and heavy rain, with the most days in a year.

Key Facts for Mertzon Thresholds

Mertzon: days with 10 mm (0.39 in) or more of precipitation in 36 years, most in 1941 with 31.
Mertzon: days with 25 mm (0.98 in) or more of precipitation in 36 years, most in 1981 with 13.
Mertzon: days with 50 mm (1.97 in) or more of precipitation in 23 years, most in 1958 with 5.
Mertzon: days with 10 cm (3.9 in) or more of snowfall in 11 years, most in 1946 with 2.
15 fixed thresholds have at least one qualifying day at Mertzon.

Days at or above 30 C (86 F)

9 years with a qualifying day

Days per year at Mertzon with a maximum temperature at or above 30 C (86 F), with the decade average as a line. The most was 161 in 1986.

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

First to last qualifying date each year at Mertzon
Year	First date	Last date
1967	1967-03-03	1967-10-27
1968	1968-05-02	1968-10-31
1980	1980-02-27	1980-11-08
1981	1981-04-09	1981-11-18
1982	1982-03-17	1982-10-07
1983	1983-04-11	1983-10-18
1984	1984-03-15	1984-10-10
1985	1985-03-11	1985-10-05
1986	1986-02-20	1986-10-07

Every Fixed Threshold

Fixed thresholds at Mertzon
Threshold	Years with a qualifying day	Most days in a year	Year	Latest year days
30 C (86 F): Days	9	161	1986	161
35 C (95 F): Days	9	91	1984	84
40 C (104 F): Days	6	13	1984	1
90 F (32.2 C): Days	9	136	1984	116
100 F (37.8 C): Days	9	32	1985	17
0 C (32 F): Ice days (max	7	6	1983	4
0 C (32 F): Frost days (min	8	73	1968	34
-10 C (14 F): Days with min	6	8	1983	2
20 C (68 F): Tropical nights (min	8	118	1984	109
25 C (77 F): Days with min	7	29	1986	29
10 mm (0.39 in): Days with 10 mm or more rain	36	31	1941	25
25 mm (0.98 in): Days with 25 mm or more rain	36	13	1981	12
50 mm (1.97 in): Days with 50 mm or more rain	23	5	1958	1
100 mm (3.94 in): Days with 100 mm or more rain	2	1	1942	1
10 cm (3.9 in): Days with 10 cm or more snowfall	11	2	1946	1

Years with under 90 percent of days observed are left out of the most days column. Threshold history at this station starts in 1967.

Download the Data

Data for Mertzon 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).

Year	Days	Decade average
1967	140	129.5
1968	119	129.5
1980	140	142.9
1981	142	142.9
1982	140	142.9
1983	128	142.9
1984	154	142.9
1985	135	142.9
1986	161	142.9

Mertzon Threshold Days by Year (USC00415859)

Key Facts for Mertzon Thresholds

Days at or above 30 C (86 F)

Every Fixed Threshold

Download the Data

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