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Rio Piedras Exp STN Weather Records (RQC00668306)

Record envelope, standing records and threshold days for Rio Piedras Exp STN (RQC00668306), PR, Puerto Rico [United States], with 62 years of record.

Key Facts for Rio Piedras Exp STN

  • Rio Piedras Exp STN (RQC00668306) is a weather station in PR, Puerto Rico [United States] at 18.39 latitude and -66.05 longitude, 28 m (92 ft) above sea level.
  • The station reports from 1959 to 2020, 62 years of record.
  • 1,464 records set at Rio Piedras Exp STN still stand.
  • Records are tracked for tmax, tmin, prcp, snow, snwd: an element needs 30 years of data to be eligible.
  • Rio Piedras Exp STN set a daily record low maximum temperature of 24.4 C (75.9 F) on 26 February 2020.

About the Station

  • Location: PR, Puerto Rico [United States], 18.39 latitude, -66.05 longitude.
  • Elevation: 28 m (92 ft).
  • Period of record: 1959 to 2020, 62 years.
  • Eligible elements: tmax, tmin, prcp, snow, snwd.

Daily Record Envelope and 2026

0 days at or beyond a record
Daily record high and record low at Rio Piedras Exp STN, with 2026 drawn through them The band shows the record high and record low for each calendar day at Rio Piedras Exp STN. The lines show the 2026 daily maximum and minimum. 0 days in 2026 matched or passed a record. Temperatures are in degrees Celsius. 010203040 JanFebMarAprMayJunJulAugSepOctNovDec
The band shows the record high and record low for each calendar day at Rio Piedras Exp STN. The lines show the 2026 daily maximum and minimum. 0 days in 2026 matched or passed a record. Temperatures are in degrees Celsius.
Daily record high and record low at Rio Piedras Exp STN, with 2026 drawn through them
MonthHighest record highLowest record low2026 highest maximum2026 lowest minimum
Jan34.4 C (93.9 F)10.0 C (50.0 F)n/an/a
Feb35.0 C (95.0 F)9.4 C (48.9 F)n/an/a
Mar35.0 C (95.0 F)10.0 C (50.0 F)n/an/a
Apr36.1 C (97.0 F)15.6 C (60.1 F)n/an/a
May36.1 C (97.0 F)15.0 C (59.0 F)n/an/a
Jun36.1 C (97.0 F)15.6 C (60.1 F)n/an/a
Jul36.7 C (98.1 F)15.6 C (60.1 F)n/an/a
Aug36.7 C (98.1 F)16.7 C (62.1 F)n/an/a
Sep37.2 C (99.0 F)16.7 C (62.1 F)n/an/a
Oct36.7 C (98.1 F)15.6 C (60.1 F)n/an/a
Nov35.0 C (95.0 F)12.8 C (55.0 F)n/an/a
Dec33.3 C (91.9 F)12.8 C (55.0 F)n/an/a

Which Years Hold Standing Records

1,464 standing records
Standing records at Rio Piedras Exp STN by the year they were set 1,464 records at Rio Piedras Exp STN still stand. 1994 holds the most, with 112. 0501001501959: 351960: 221961: 231963: 221964: 311965: 481966: 341967: 191968: 261969: 331970: 401971: 251972: 171973: 241974: 291975: 321976: 311977: 261978: 61979: 161980: 281981: 171982: 71983: 291984: 171985: 101986: 51987: 431988: 161989: 231990: 211991: 231992: 101993: 781994: 1121995: 711996: 81997: 211998: 271999: 152000: 102001: 172002: 152003: 132004: 42005: 242006: 112007: 162008: 102009: 122010: 382011: 202012: 202013: 72014: 262015: 342016: 312017: 52019: 262020: 51959196619721978198419901996200220082014
1,464 records at Rio Piedras Exp STN still stand. 1994 holds the most, with 112.
Standing records at Rio Piedras Exp STN by the year they were set
Year setStanding records
195935
196022
196123
196322
196431
196548
196634
196719
196826
196933
197040
197125
197217
197324
197429
197532
197631
197726
19786
197916
198028
198117
19827
198329
198417
198510
19865
198743
198816
198923
199021
199123
199210
199378
1994112
199571
19968
199721
199827
199915
200010
200117
200215
200313
20044
200524
200611
200716
200810
200912
201038
201120
201220
20137
201426
201534
201631
20175
201926
20205

All-Time Record Progression

7 new records
When Rio Piedras Exp STN set new all-time records 7 all-time records were set at Rio Piedras Exp STN between 3 March 1993 and 25 August 2011. Each dot is a new record. Record low minimum temperatureRecord high maximum temperatureRecord daily precipitation3 March 1993: Record low minimum temperature 11.7 C (53.1 F)13 January 1995: Record low minimum temperature 10.6 C (51.1 F)18 January 1995: Record low minimum temperature 10.0 C (50.0 F)26 February 1995: Record low minimum temperature 9.4 C (48.9 F)10 August 1998: Record high maximum temperature 36.7 C (98.1 F)25 September 2000: Record high maximum temperature 37.2 C (99.0 F)25 August 2011: Record daily precipitation 340.4 mm (13.4 in)1995200020052010
7 all-time records were set at Rio Piedras Exp STN between 3 March 1993 and 25 August 2011. Each dot is a new record.
When Rio Piedras Exp STN set new all-time records
DateKindDetail
1993-03-03Record low minimum temperatureRecord low minimum temperature 11.7 C (53.1 F)
1995-01-13Record low minimum temperatureRecord low minimum temperature 10.6 C (51.1 F)
1995-01-18Record low minimum temperatureRecord low minimum temperature 10.0 C (50.0 F)
1995-02-26Record low minimum temperatureRecord low minimum temperature 9.4 C (48.9 F)
1998-08-10Record high maximum temperatureRecord high maximum temperature 36.7 C (98.1 F)
2000-09-25Record high maximum temperatureRecord high maximum temperature 37.2 C (99.0 F)
2011-08-25Record daily precipitationRecord daily precipitation 340.4 mm (13.4 in)

Wettest Day of Each Month

Aug: 340.4 mm (13.4 in)
Record daily precipitation for each month at Rio Piedras Exp STN The wettest day on record for each calendar month at Rio Piedras Exp STN. The most was 340.4 mm (13.4 in) on 25 August 2011. 0100200300400 Jan: 119.4 mm (4.7 in), 21 January 1977 Jan Feb: 167.9 mm (6.6 in), 15 February 1979 Feb Mar: 93.0 mm (3.7 in), 1 March 1969 Mar Apr: 210.8 mm (8.3 in), 23 April 1973 Apr May: 156.5 mm (6.2 in), 14 May 1979 May Jun: 186.9 mm (7.4 in), 17 June 1970 Jun Jul: 155.4 mm (6.1 in), 14 July 2016 Jul Aug: 340.4 mm (13.4 in), 25 August 2011 Aug Sep: 127.0 mm (5.0 in), 19 September 1978 Sep Oct: 123.2 mm (4.9 in), 6 October 1970 Oct Nov: 162.1 mm (6.4 in), 26 November 1979 Nov Dec: 137.2 mm (5.4 in), 2 December 2013 Dec
The wettest day on record for each calendar month at Rio Piedras Exp STN. The most was 340.4 mm (13.4 in) on 25 August 2011.
Record daily precipitation for each month at Rio Piedras Exp STN
MonthRecord daily precipitation (mm)Date
Jan119.4 mm (4.7 in)21 January 1977
Feb167.9 mm (6.6 in)15 February 1979
Mar93.0 mm (3.7 in)1 March 1969
Apr210.8 mm (8.3 in)23 April 1973
May156.5 mm (6.2 in)14 May 1979
Jun186.9 mm (7.4 in)17 June 1970
Jul155.4 mm (6.1 in)14 July 2016
Aug340.4 mm (13.4 in)25 August 2011
Sep127.0 mm (5.0 in)19 September 1978
Oct123.2 mm (4.9 in)6 October 1970
Nov162.1 mm (6.4 in)26 November 1979
Dec137.2 mm (5.4 in)2 December 2013

Period of Record Coverage

1959 to 2020
Days with data per year at Rio Piedras Exp STN 60 years of record at Rio Piedras Exp STN, 1959 to 2020. 22 years have data for under 90 percent of days and are left out of rankings: 1992, 1998, 1999, 2000, 2002, 2003, 2004, 2005 and others. 1959: 363 of 365 days1960: 356 of 366 days1961: 361 of 365 days1963: 364 of 365 days1964: 364 of 366 days1965: 363 of 365 days1966: 364 of 365 days1967: 363 of 365 days1968: 363 of 366 days1969: 364 of 365 days1970: 360 of 365 days1971: 362 of 365 days1972: 366 of 366 days1973: 365 of 365 days1974: 365 of 365 days1975: 364 of 365 days1976: 360 of 366 days1977: 364 of 365 days1978: 362 of 365 days1979: 360 of 365 days1980: 366 of 366 days1981: 365 of 365 days1982: 364 of 365 days1983: 364 of 365 days1984: 366 of 366 days1985: 334 of 365 days1986: 364 of 365 days1987: 355 of 365 days1988: 366 of 366 days1989: 361 of 365 days1990: 365 of 365 days1991: 359 of 365 days1992: 299 of 366 days1993: 361 of 365 days1994: 365 of 365 days1995: 332 of 365 days1996: 364 of 366 days1997: 334 of 365 days1998: 328 of 365 days1999: 304 of 365 days2000: 182 of 366 days2001: 330 of 365 days2002: 186 of 365 days2003: 202 of 365 days2004: 186 of 366 days2005: 192 of 365 days2006: 207 of 365 days2007: 172 of 365 days2008: 153 of 366 days2009: 183 of 365 days2010: 197 of 365 days2011: 207 of 365 days2012: 166 of 366 days2013: 116 of 365 days2014: 169 of 365 days2015: 181 of 365 days2016: 288 of 366 days2017: 179 of 365 days2019: 263 of 365 days2020: 37 of 366 days1960197019801990200020102020
60 years of record at Rio Piedras Exp STN, 1959 to 2020. 22 years have data for under 90 percent of days and are left out of rankings: 1992, 1998, 1999, 2000, 2002, 2003, 2004, 2005 and others.
Days with data per year at Rio Piedras Exp STN
YearDays with dataShare of yearComplete
195936399%Yes
196035697%Yes
196136199%Yes
1963364100%Yes
196436499%Yes
196536399%Yes
1966364100%Yes
196736399%Yes
196836399%Yes
1969364100%Yes
197036099%Yes
197136299%Yes
1972366100%Yes
1973365100%Yes
1974365100%Yes
1975364100%Yes
197636098%Yes
1977364100%Yes
197836299%Yes
197936099%Yes
1980366100%Yes
1981365100%Yes
1982364100%Yes
1983364100%Yes
1984366100%Yes
198533492%Yes
1986364100%Yes
198735597%Yes
1988366100%Yes
198936199%Yes
1990365100%Yes
199135998%Yes
199229982%No
199336199%Yes
1994365100%Yes
199533291%Yes
199636499%Yes
199733492%Yes
199832890%No
199930483%No
200018250%No
200133090%Yes
200218651%No
200320255%No
200418651%No
200519253%No
200620757%No
200717247%No
200815342%No
200918350%No
201019754%No
201120757%No
201216645%No
201311632%No
201416946%No
201518150%No
201628879%No
201717949%No
201926372%No
20203710%No

Latest Records

20
Latest records at Rio Piedras Exp STN
DateStationRecordValueBeat old record byOld record stoodSignificance
26 February 2020Rio Piedras Exp STN, PRdaily low max24.4 C (75.9 F)2.3 C (4.1 F)34 years29 of 100 (Routine)
25 February 2020Rio Piedras Exp STN, PRdaily low max25.0 C (77.0 F)1.1 C (2.0 F)37 years23 of 100 (Routine)
25 February 2020Rio Piedras Exp STN, PRdaily high min (Tie)21.7 C (71.1 F)tie46 years5 of 100 (Routine)
14 February 2020Rio Piedras Exp STN, PRdaily high min (Tie)21.1 C (70.0 F)tie58 years5 of 100 (Routine)
10 February 2020Rio Piedras Exp STN, PRdaily high min21.7 C (71.1 F)0.6 C (1.1 F)56 years26 of 100 (Routine)
9 February 2020Rio Piedras Exp STN, PRdaily high min (Tie)21.1 C (70.0 F)tie32 years3 of 100 (Routine)
6 February 2020Rio Piedras Exp STN, PRdaily high min21.7 C (71.1 F)0.6 C (1.1 F)37 years20 of 100 (Routine)
1 February 2020Rio Piedras Exp STN, PRdaily high min (Tie)21.1 C (70.0 F)tie44 years4 of 100 (Routine)
24 January 2020Rio Piedras Exp STN, PRdaily high min (Tie)21.1 C (70.0 F)tie60 years6 of 100 (Routine)
23 January 2020Rio Piedras Exp STN, PRdaily high min22.2 C (72.0 F)0.5 C (0.9 F)32 years18 of 100 (Routine)
19 January 2020Rio Piedras Exp STN, PRdaily high min (Tie)21.1 C (70.0 F)tie24 years3 of 100 (Routine)
6 December 2019Rio Piedras Exp STN, PRdaily high min22.8 C (73.0 F)0.6 C (1.1 F)52 years24 of 100 (Routine)
5 December 2019Rio Piedras Exp STN, PRdaily high max32.2 C (90.0 F)0.5 C (0.9 F)60 years27 of 100 (Routine)
5 December 2019Rio Piedras Exp STN, PRdaily high min22.8 C (73.0 F)0.6 C (1.1 F)58 years26 of 100 (Routine)
4 December 2019Rio Piedras Exp STN, PRdaily high max32.8 C (91.0 F)1.1 C (2.0 F)52 years28 of 100 (Routine)
4 December 2019Rio Piedras Exp STN, PRdaily high min (Tie)22.8 C (73.0 F)tie18 years2 of 100 (Routine)
28 November 2019Rio Piedras Exp STN, PRdaily high min (Tie)22.8 C (73.0 F)tie40 years4 of 100 (Routine)
27 November 2019Rio Piedras Exp STN, PRdaily high min (Tie)23.3 C (73.9 F)tie60 years6 of 100 (Routine)
23 November 2019Rio Piedras Exp STN, PRdaily high min (Tie)22.8 C (73.0 F)tie29 years3 of 100 (Routine)
21 November 2019Rio Piedras Exp STN, PRdaily rain50.5 mm (2.0 in)24.3 mm (1.0 in)24 years28 of 100 (Routine)

Climate Trend

33 complete years, 1959 to 1996
Annual mean temperature at Rio Piedras Exp STN as warming stripes, 1959 to 1996 One stripe for each of 33 complete years at Rio Piedras Exp STN, 1959 to 1996. Blue stripes are years cooler than the station's own mean of 25.6 C (78.1 F); red stripes are warmer. The coolest year was 1975, at 24.9 C (76.8 F), and the warmest was 1987, at 26.5 C (79.7 F). The strongest colour marks a difference of 0.9 C (1.6 F). 1959: 25.6 C, 0.0 C from the station mean1960: 26.0 C, +0.3 C from the station mean1961: 25.4 C, -0.2 C from the station mean1963: 25.6 C, 0.0 C from the station mean1964: 25.5 C, -0.2 C from the station mean1965: 25.0 C, -0.6 C from the station mean1966: 25.4 C, -0.2 C from the station mean1967: 25.2 C, -0.4 C from the station mean1968: 25.3 C, -0.4 C from the station mean1969: 25.9 C, +0.3 C from the station mean1970: 25.4 C, -0.2 C from the station mean1971: 25.4 C, -0.2 C from the station mean1972: 25.7 C, +0.1 C from the station mean1973: 26.1 C, +0.5 C from the station mean1974: 25.2 C, -0.4 C from the station mean1975: 24.9 C, -0.7 C from the station mean1976: 25.0 C, -0.6 C from the station mean1977: 25.4 C, -0.2 C from the station mean1978: 25.6 C, 0.0 C from the station mean1979: 25.5 C, -0.1 C from the station mean1980: 26.1 C, +0.5 C from the station mean1981: 26.1 C, +0.5 C from the station mean1982: 25.5 C, -0.2 C from the station mean1983: 26.1 C, +0.4 C from the station mean1984: 25.4 C, -0.2 C from the station mean1986: 25.7 C, +0.1 C from the station mean1987: 26.5 C, +0.9 C from the station mean1988: 26.1 C, +0.5 C from the station mean1989: 25.7 C, +0.1 C from the station mean1990: 26.1 C, +0.5 C from the station mean1991: 26.0 C, +0.4 C from the station mean1993: 25.2 C, -0.4 C from the station mean1996: 25.7 C, 0.0 C from the station mean19591965197019751980198519901995
One stripe for each of 33 complete years at Rio Piedras Exp STN, 1959 to 1996. Blue stripes are years cooler than the station's own mean of 25.6 C (78.1 F); red stripes are warmer. The coolest year was 1975, at 24.9 C (76.8 F), and the warmest was 1987, at 26.5 C (79.7 F). The strongest colour marks a difference of 0.9 C (1.6 F).
Annual mean temperature at Rio Piedras Exp STN as warming stripes, 1959 to 1996
YearAnnual mean temperatureDifference from the station mean
195925.6 C-0.02 C
196026.0 C+0.34 C
196125.4 C-0.20 C
196325.6 C-0.01 C
196425.5 C-0.16 C
196525.0 C-0.59 C
196625.4 C-0.18 C
196725.2 C-0.38 C
196825.3 C-0.37 C
196925.9 C+0.27 C
197025.4 C-0.18 C
197125.4 C-0.21 C
197225.7 C+0.06 C
197326.1 C+0.52 C
197425.2 C-0.38 C
197524.9 C-0.71 C
197625.0 C-0.58 C
197725.4 C-0.18 C
197825.6 C-0.03 C
197925.5 C-0.11 C
198026.1 C+0.51 C
198126.1 C+0.48 C
198225.5 C-0.15 C
198326.1 C+0.43 C
198425.4 C-0.22 C
198625.7 C+0.08 C
198726.5 C+0.89 C
198826.1 C+0.51 C
198925.7 C+0.07 C
199026.1 C+0.50 C
199126.0 C+0.41 C
199325.2 C-0.38 C
199625.7 C+0.05 C

The annual mean temperature here has risen by 0.13 C (0.00 to 0.26) per decade over 1959 to 1996. In Fahrenheit: 0.23 F (0.00 to 0.46) per decade. The slope is a straight line fitted to 33 complete years; the brackets give its 95 percent interval.

Fitted temperature trends per decade at Rio Piedras Exp STN
MeasurePer decade (C)Per decade (F)PeriodComplete yearsReading
Annual mean temperature0.13 C (0.00 to 0.26) per decade0.23 F (0.00 to 0.46) per decade1959 to 199633Rise
Mean daily maximum0.2 C (0.1 to 0.3) per decade0.4 F (0.1 to 0.6) per decade1959 to 199633Rise
Mean daily minimum0.1 C (-0.1 to 0.2) per decade0.1 F (-0.2 to 0.4) per decade1959 to 199633Not clearly different from zero

A year is complete when all 12 months have at least 20 days of both daily maximum and daily minimum readings. The annual mean is the mean of the monthly means. The trend describes this one station over this period; it does not say what caused the change.

Extremes by Year

1959 to 2020
Yearly extremes at Rio Piedras Exp STN: the record and the median year
MeasureRecordYear of the recordMedian yearYears with a value
Hottest day (TXx)37.2 C (99.0 F)200035.0 C (95.0 F)60
Coldest night (TNn)9.4 C (48.9 F)199515.9 C (60.5 F)60
Wettest day (Rx1day)340.4 mm (13.4 in)201180.7 mm (3.2 in)60
Wettest five days (Rx5day)376.8 mm (14.8 in)1970127.8 mm (5.0 in)59
Longest dry spell (CDD)39 days198414 days59

Hottest day (TXx)

Hottest day (TXx) at Rio Piedras Exp STN by year The hottest day of the year at Rio Piedras Exp STN, 1959 to 2020. The record is 37.2 C (99.0 F) in 2000, marked on the chart; the median year is 35.0 C (95.0 F). 30323436381960198020002020Record: 37.2 C (99.0 F) in 2000
The hottest day of the year at Rio Piedras Exp STN, 1959 to 2020. The record is 37.2 C (99.0 F) in 2000, marked on the chart; the median year is 35.0 C (95.0 F).
Hottest day (TXx) at Rio Piedras Exp STN by year
YearHottest day (TXx)
195935.0 C (95.0 F)
196035.0 C (95.0 F)
196134.4 C (93.9 F)
196334.4 C (93.9 F)
196433.3 C (91.9 F)
196532.8 C (91.0 F)
196635.0 C (95.0 F)
196733.9 C (93.0 F)
196833.3 C (91.9 F)
196934.4 C (93.9 F)
197033.3 C (91.9 F)
197133.9 C (93.0 F)
197235.0 C (95.0 F)
197335.0 C (95.0 F)
197435.0 C (95.0 F)
197534.4 C (93.9 F)
197633.9 C (93.0 F)
197733.9 C (93.0 F)
197833.3 C (91.9 F)
197933.9 C (93.0 F)
198035.0 C (95.0 F)
198135.0 C (95.0 F)
198234.4 C (93.9 F)
198335.6 C (96.1 F)
198434.4 C (93.9 F)
198533.9 C (93.0 F)
198633.9 C (93.0 F)
198735.0 C (95.0 F)
198834.4 C (93.9 F)
198935.6 C (96.1 F)
199033.9 C (93.0 F)
199134.4 C (93.9 F)
199233.9 C (93.0 F)
199335.0 C (95.0 F)
199435.0 C (95.0 F)
199535.0 C (95.0 F)
199635.0 C (95.0 F)
199735.0 C (95.0 F)
199836.7 C (98.1 F)
199934.4 C (93.9 F)
200037.2 C (99.0 F)
200135.0 C (95.0 F)
200236.7 C (98.1 F)
200335.0 C (95.0 F)
200435.0 C (95.0 F)
200535.6 C (96.1 F)
200635.0 C (95.0 F)
200735.6 C (96.1 F)
200835.6 C (96.1 F)
200935.6 C (96.1 F)
201036.1 C (97.0 F)
201135.0 C (95.0 F)
201236.1 C (97.0 F)
201336.7 C (98.1 F)
201435.6 C (96.1 F)
201536.1 C (97.0 F)
201635.0 C (95.0 F)
201733.3 C (91.9 F)
201934.4 C (93.9 F)
202031.1 C (88.0 F)

Coldest night (TNn)

Coldest night (TNn) at Rio Piedras Exp STN by year The coldest night of the year at Rio Piedras Exp STN, 1959 to 2020. The record is 9.4 C (48.9 F) in 1995, marked on the chart; the median year is 15.9 C (60.5 F). 7.51012.51517.5201960198020002020Record: 9.4 C (48.9 F) in 1995
The coldest night of the year at Rio Piedras Exp STN, 1959 to 2020. The record is 9.4 C (48.9 F) in 1995, marked on the chart; the median year is 15.9 C (60.5 F).
Coldest night (TNn) at Rio Piedras Exp STN by year
YearColdest night (TNn)
195916.7 C (62.1 F)
196015.6 C (60.1 F)
196116.1 C (61.0 F)
196317.2 C (63.0 F)
196415.0 C (59.0 F)
196515.0 C (59.0 F)
196617.2 C (63.0 F)
196715.6 C (60.1 F)
196814.4 C (57.9 F)
196915.6 C (60.1 F)
197014.4 C (57.9 F)
197115.6 C (60.1 F)
197216.1 C (61.0 F)
197315.6 C (60.1 F)
197415.6 C (60.1 F)
197515.0 C (59.0 F)
197615.0 C (59.0 F)
197715.6 C (60.1 F)
197815.6 C (60.1 F)
197915.0 C (59.0 F)
198014.4 C (57.9 F)
198116.1 C (61.0 F)
198216.7 C (62.1 F)
198316.7 C (62.1 F)
198415.6 C (60.1 F)
198516.1 C (61.0 F)
198616.1 C (61.0 F)
198717.2 C (63.0 F)
198815.6 C (60.1 F)
198915.6 C (60.1 F)
199016.1 C (61.0 F)
199115.6 C (60.1 F)
199216.7 C (62.1 F)
199311.7 C (53.1 F)
199412.8 C (55.0 F)
19959.4 C (48.9 F)
199616.1 C (61.0 F)
199716.7 C (62.1 F)
199817.2 C (63.0 F)
199915.6 C (60.1 F)
200018.3 C (64.9 F)
200117.2 C (63.0 F)
200217.8 C (64.0 F)
200318.3 C (64.9 F)
200415.6 C (60.1 F)
200515.0 C (59.0 F)
200616.7 C (62.1 F)
200717.8 C (64.0 F)
200816.1 C (61.0 F)
200915.0 C (59.0 F)
201015.0 C (59.0 F)
201115.6 C (60.1 F)
201216.1 C (61.0 F)
201316.7 C (62.1 F)
201416.1 C (61.0 F)
201516.1 C (61.0 F)
201616.1 C (61.0 F)
201715.6 C (60.1 F)
201917.8 C (64.0 F)
202018.9 C (66.0 F)

Wettest day (Rx1day)

Wettest day (Rx1day) at Rio Piedras Exp STN by year The wettest day of the year at Rio Piedras Exp STN, 1959 to 2020. The record is 340.4 mm (13.4 in) in 2011, marked on the chart; the median year is 80.7 mm (3.2 in). 01002003004001960198020002020Record: 340.4 mm (13.4 in) in 2011
The wettest day of the year at Rio Piedras Exp STN, 1959 to 2020. The record is 340.4 mm (13.4 in) in 2011, marked on the chart; the median year is 80.7 mm (3.2 in).
Wettest day (Rx1day) at Rio Piedras Exp STN by year
YearWettest day (Rx1day)
195971.4 mm (2.8 in)
196064.3 mm (2.5 in)
1961145.8 mm (5.7 in)
196378.0 mm (3.1 in)
196481.8 mm (3.2 in)
1965107.4 mm (4.2 in)
1966104.6 mm (4.1 in)
196739.1 mm (1.5 in)
1968113.3 mm (4.5 in)
196993.0 mm (3.7 in)
1970186.9 mm (7.4 in)
197150.8 mm (2.0 in)
197284.6 mm (3.3 in)
1973210.8 mm (8.3 in)
1974111.3 mm (4.4 in)
197581.3 mm (3.2 in)
197674.2 mm (2.9 in)
1977119.4 mm (4.7 in)
1978142.5 mm (5.6 in)
1979167.9 mm (6.6 in)
198062.0 mm (2.4 in)
198184.1 mm (3.3 in)
198268.8 mm (2.7 in)
1983100.3 mm (3.9 in)
198465.3 mm (2.6 in)
198580.0 mm (3.1 in)
198657.9 mm (2.3 in)
198793.0 mm (3.7 in)
198861.0 mm (2.4 in)
198970.1 mm (2.8 in)
199052.1 mm (2.1 in)
199152.8 mm (2.1 in)
199250.8 mm (2.0 in)
199353.3 mm (2.1 in)
199453.3 mm (2.1 in)
199557.2 mm (2.3 in)
199650.8 mm (2.0 in)
199754.6 mm (2.1 in)
199852.3 mm (2.1 in)
199950.8 mm (2.0 in)
2000106.7 mm (4.2 in)
200183.3 mm (3.3 in)
2002110.7 mm (4.4 in)
2003121.4 mm (4.8 in)
2004110.7 mm (4.4 in)
200550.3 mm (2.0 in)
2006119.6 mm (4.7 in)
2007102.9 mm (4.1 in)
200874.9 mm (2.9 in)
200972.9 mm (2.9 in)
201095.8 mm (3.8 in)
2011340.4 mm (13.4 in)
2012116.8 mm (4.6 in)
2013137.2 mm (5.4 in)
2014115.3 mm (4.5 in)
201559.7 mm (2.4 in)
2016155.4 mm (6.1 in)
201744.7 mm (1.8 in)
201950.5 mm (2.0 in)
20202.5 mm (0.10 in)

Wettest five days (Rx5day)

Wettest five days (Rx5day) at Rio Piedras Exp STN by year The wettest five days of the year at Rio Piedras Exp STN, 1959 to 2020. The record is 376.8 mm (14.8 in) in 1970, marked on the chart; the median year is 127.8 mm (5.0 in). 01002003004001960198020002020Record: 376.8 mm (14.8 in) in 1970
The wettest five days of the year at Rio Piedras Exp STN, 1959 to 2020. The record is 376.8 mm (14.8 in) in 1970, marked on the chart; the median year is 127.8 mm (5.0 in).
Wettest five days (Rx5day) at Rio Piedras Exp STN by year
YearWettest five days (Rx5day)
1959128.8 mm (5.1 in)
1960111.9 mm (4.4 in)
1961233.2 mm (9.2 in)
1963103.3 mm (4.1 in)
1964136.6 mm (5.4 in)
1965178.8 mm (7.0 in)
1966175.7 mm (6.9 in)
196776.2 mm (3.0 in)
1968233.9 mm (9.2 in)
1969130.9 mm (5.2 in)
1970376.8 mm (14.8 in)
1971119.9 mm (4.7 in)
1972107.2 mm (4.2 in)
1973343.2 mm (13.5 in)
1974252.0 mm (9.9 in)
1975177.6 mm (7.0 in)
1976123.3 mm (4.9 in)
1977245.5 mm (9.7 in)
1978157.0 mm (6.2 in)
1979268.2 mm (10.6 in)
198087.1 mm (3.4 in)
1981207.5 mm (8.2 in)
1982160.5 mm (6.3 in)
1983166.1 mm (6.5 in)
1984121.4 mm (4.8 in)
1985168.9 mm (6.6 in)
1986154.0 mm (6.1 in)
1987222.8 mm (8.8 in)
1988169.9 mm (6.7 in)
1989161.9 mm (6.4 in)
1990110.0 mm (4.3 in)
1991127.8 mm (5.0 in)
1992114.6 mm (4.5 in)
199398.0 mm (3.9 in)
199491.8 mm (3.6 in)
1995116.8 mm (4.6 in)
1996104.4 mm (4.1 in)
199792.5 mm (3.6 in)
1998131.8 mm (5.2 in)
1999100.6 mm (4.0 in)
2000125.5 mm (4.9 in)
2001211.2 mm (8.3 in)
2002148.0 mm (5.8 in)
2003125.5 mm (4.9 in)
200482.8 mm (3.3 in)
200560.2 mm (2.4 in)
2006128.7 mm (5.1 in)
2007109.0 mm (4.3 in)
200812.9 mm (0.5 in)
2009103.4 mm (4.1 in)
201087.9 mm (3.5 in)
201148.0 mm (1.9 in)
201269.6 mm (2.7 in)
2013243.6 mm (9.6 in)
2014157.2 mm (6.2 in)
201531.0 mm (1.2 in)
2016190.2 mm (7.5 in)
201718.1 mm (0.7 in)
201950.5 mm (2.0 in)
2020n/a

Longest dry spell (CDD)

Longest dry spell (CDD) at Rio Piedras Exp STN by year The longest dry spell of the year at Rio Piedras Exp STN, 1959 to 2020. The record is 39 days in 1984, marked on the chart; the median year is 14 days. 0102030401960198020002020Record: 39 days in 1984
The longest dry spell of the year at Rio Piedras Exp STN, 1959 to 2020. The record is 39 days in 1984, marked on the chart; the median year is 14 days.
Longest dry spell (CDD) at Rio Piedras Exp STN by year
YearLongest dry spell (CDD)
195913 days
196015 days
196112 days
196314 days
196420 days
196516 days
196617 days
196715 days
196812 days
196914 days
197016 days
197112 days
197215 days
197333 days
197418 days
197515 days
197616 days
197714 days
197812 days
197910 days
198020 days
198116 days
198217 days
198314 days
198439 days
198517 days
198615 days
198714 days
198815 days
198916 days
199013 days
199111 days
19929 days
199314 days
199416 days
199518 days
199613 days
199714 days
199812 days
199914 days
200010 days
200112 days
200211 days
200312 days
200413 days
200525 days
200612 days
200714 days
20088 days
20095 days
20109 days
20114 days
20123 days
20133 days
20145 days
20154 days
20165 days
20175 days
201910 days
2020n/a

Each chart shows one value per year; the dot marks the record year. TXx is the hottest daily maximum, TNn the coldest daily minimum, Rx1day and Rx5day the largest one-day and five-day rain totals, and CDD the longest run of days with less than 1 mm of rain. A year with missing days can understate an extreme.

Rainfall Return Levels

38 years, 1959 to 2001

A day with at least 76.5 mm (3.0 in) of rain is expected about once in 2 years. A day with at least 254.3 mm (10.0 in) of rain is expected about once in 100 years.

Rainfall return levels at Rio Piedras Exp STN: the daily rain expected about once in a given number of years
Expected about once inA day with at leastNote
2 years76.5 mm (3.0 in)
5 years108.8 mm (4.3 in)
10 years135.3 mm (5.3 in)
25 years175.8 mm (6.9 in)
50 years212.1 mm (8.4 in)Longer than the 38 years of record
100 years254.3 mm (10.0 in)Longer than the 38 years of record

The levels come from a generalised extreme value (GEV) distribution fitted by L-moments to the wettest-day total of each year, 38 years of values from 1959 to 2001.

A return level is an estimate. It is least reliable for the long periods, 50 and 100 years, and for any period longer than the record behind the fit, where the fit has to reach past the largest day actually observed. It is not a forecast.

The largest wettest-day totals in the fit: 210.8 mm (8.3 in) in 1973; 186.9 mm (7.4 in) in 1970; 167.9 mm (6.6 in) in 1979.

Download the Data

  • Data for Rio Piedras Exp STN standing records by year: CSV or JSON. Field meanings are on the data page.
  • 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 2026-10-16 (16 October 2026). Records are computed by this site and are not official.

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