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Built 2026-10-19 (19 October 2026)

Rio Piedras Exp STN Threshold Days by Year (RQC00668306)

10 fixed thresholds counted per year at Rio Piedras Exp STN (RQC00668306): hot days, frost, tropical nights and heavy rain, with the most days in a year.

Key Facts for Rio Piedras Exp STN Thresholds

  • Rio Piedras Exp STN: days with a maximum temperature at or above 30 C (86 F) in 38 years, most in 1994 with 301.
  • Rio Piedras Exp STN: days with a maximum temperature at or above 90 F (32.2 C) in 38 years, most in 2001 with 167.
  • Rio Piedras Exp STN: days with 10 mm (0.39 in) or more of precipitation in 38 years, most in 1979 with 72.
  • Rio Piedras Exp STN: days with 25 mm (0.98 in) or more of precipitation in 38 years, most in 1987 with 29.
  • 10 fixed thresholds have at least one qualifying day at Rio Piedras Exp STN.
38 years with a qualifying day
Days at or above 30 C (86 F) per year at Rio Piedras Exp STN Days per year at Rio Piedras Exp STN with a maximum temperature at or above 30 C (86 F), with the decade average as a line. The most was 301 in 1994. 01002003004001959: 2581960: 2941961: 2281963: 2301964: 2271965: 1891966: 2061967: 1801968: 2041969: 2361970: 1941971: 2331972: 2351973: 2791974: 2071975: 1981976: 2371977: 2221978: 2401979: 2021980: 2791981: 2461982: 2331983: 2711984: 2301985: 2131986: 2641987: 2821988: 2481989: 2341990: 2301991: 2461993: 2891994: 3011995: 2691996: 2421997: 2522001: 2861959196419681972197619801984198819931997
Days per year at Rio Piedras Exp STN with a maximum temperature at or above 30 C (86 F), with the decade average as a line. The most was 301 in 1994.
Days at or above 30 C (86 F) per year at Rio Piedras Exp STN
YearDaysDecade average
1959258258
1960294221.6
1961228221.6
1963230221.6
1964227221.6
1965189221.6
1966206221.6
1967180221.6
1968204221.6
1969236221.6
1970194224.7
1971233224.7
1972235224.7
1973279224.7
1974207224.7
1975198224.7
1976237224.7
1977222224.7
1978240224.7
1979202224.7
1980279250
1981246250
1982233250
1983271250
1984230250
1985213250
1986264250
1987282250
1988248250
1989234250
1990230261.3
1991246261.3
1993289261.3
1994301261.3
1995269261.3
1996242261.3
1997252261.3
2001286286
First to last qualifying date each year at Rio Piedras Exp STN For each year, a bar from the first to the last day at Rio Piedras Exp STN meeting 30 C (86 F). 1959: 2 January 1959 to 27 December 19591960: 1 January 1960 to 14 December 19601961: 10 January 1961 to 30 December 19611963: 10 January 1963 to 31 December 19631964: 1 January 1964 to 2 December 19641965: 20 February 1965 to 24 December 19651966: 9 January 1966 to 21 December 19661967: 14 February 1967 to 12 December 19671968: 13 February 1968 to 18 December 19681969: 7 January 1969 to 29 December 19691970: 4 January 1970 to 30 December 19701971: 2 January 1971 to 5 December 19711972: 12 January 1972 to 29 December 19721973: 3 January 1973 to 28 December 19731974: 19 February 1974 to 15 December 19741975: 9 February 1975 to 25 November 19751976: 4 February 1976 to 31 December 19761977: 6 January 1977 to 29 December 19771978: 5 January 1978 to 29 December 19781979: 23 January 1979 to 20 December 19791980: 2 January 1980 to 30 December 19801981: 1 January 1981 to 21 December 19811982: 11 January 1982 to 10 December 19821983: 11 January 1983 to 28 December 19831984: 17 January 1984 to 11 December 19841985: 7 February 1985 to 25 December 19851986: 9 January 1986 to 31 December 19861987: 1 January 1987 to 30 December 19871988: 10 January 1988 to 23 December 19881989: 4 January 1989 to 31 December 19891990: 1 January 1990 to 27 December 19901991: 21 January 1991 to 20 December 19911993: 2 January 1993 to 31 December 19931994: 1 January 1994 to 29 December 19941995: 1 January 1995 to 29 December 19951996: 1 January 1996 to 15 December 19961997: 16 January 1997 to 31 December 19972001: 1 January 2001 to 31 December 200119591965197019751980198519901996JanFebMarAprMayJunJulAugSepOctNovDec
For each year, a bar from the first to the last day at Rio Piedras Exp STN meeting 30 C (86 F).
First to last qualifying date each year at Rio Piedras Exp STN
YearFirst dateLast date
19591959-01-021959-12-27
19601960-01-011960-12-14
19611961-01-101961-12-30
19631963-01-101963-12-31
19641964-01-011964-12-02
19651965-02-201965-12-24
19661966-01-091966-12-21
19671967-02-141967-12-12
19681968-02-131968-12-18
19691969-01-071969-12-29
19701970-01-041970-12-30
19711971-01-021971-12-05
19721972-01-121972-12-29
19731973-01-031973-12-28
19741974-02-191974-12-15
19751975-02-091975-11-25
19761976-02-041976-12-31
19771977-01-061977-12-29
19781978-01-051978-12-29
19791979-01-231979-12-20
19801980-01-021980-12-30
19811981-01-011981-12-21
19821982-01-111982-12-10
19831983-01-111983-12-28
19841984-01-171984-12-11
19851985-02-071985-12-25
19861986-01-091986-12-31
19871987-01-011987-12-30
19881988-01-101988-12-23
19891989-01-041989-12-31
19901990-01-011990-12-27
19911991-01-211991-12-20
19931993-01-021993-12-31
19941994-01-011994-12-29
19951995-01-011995-12-29
19961996-01-011996-12-15
19971997-01-161997-12-31
20012001-01-012001-12-31

Every Fixed Threshold

Fixed thresholds at Rio Piedras Exp STN
ThresholdYears with a qualifying dayMost days in a yearYearLatest year days
30 C (86 F): Days383011994286
35 C (95 F): Days17519971
90 F (32.2 C): Days381672001167
20 C (68 F): Tropical nights (min363101981262
25 C (77 F): Days with min281219903
10 mm (0.39 in): Days with 10 mm or more rain3872197946
25 mm (0.98 in): Days with 25 mm or more rain3829198718
50 mm (1.97 in): Days with 50 mm or more rain3713197010
100 mm (3.94 in): Days with 100 mm or more rain11519791
200 mm (7.87 in): Days with 200 mm or more rain1119731

Years with under 90 percent of days observed are left out of the most days column. Threshold history at this station starts in 1959.

Download the Data

  • Data for Rio Piedras Exp STN 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 . Last revised (2025-12-31).