Record highRecord low2026 daily maximum2026 daily minimum
The band shows the record high and record low for each calendar day at San Isidro. 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 San Isidro, with 2026 drawn through them
Month
Highest record high
Lowest record low
2026 highest maximum
2026 lowest minimum
Jan
37.8 C (100.0 F)
-6.7 C (19.9 F)
n/a
n/a
Feb
37.8 C (100.0 F)
-5.0 C (23.0 F)
n/a
n/a
Mar
40.6 C (105.1 F)
-1.7 C (28.9 F)
n/a
n/a
Apr
43.9 C (111.0 F)
1.1 C (34.0 F)
n/a
n/a
May
47.8 C (118.0 F)
2.8 C (37.0 F)
n/a
n/a
Jun
50.6 C (123.1 F)
8.9 C (48.0 F)
n/a
n/a
Jul
50.0 C (122.0 F)
12.8 C (55.0 F)
n/a
n/a
Aug
46.7 C (116.1 F)
15.0 C (59.0 F)
n/a
n/a
Sep
47.8 C (118.0 F)
10.6 C (51.1 F)
n/a
n/a
Oct
45.6 C (114.1 F)
1.7 C (35.1 F)
n/a
n/a
Nov
41.7 C (107.1 F)
-1.1 C (30.0 F)
n/a
n/a
Dec
33.9 C (93.0 F)
-3.9 C (25.0 F)
n/a
n/a
Which Years Hold Standing Records
1,464 standing records
Year with most
1,464 records at San Isidro still stand. 2008 holds the most, with 97.
Standing records at San Isidro by the year they were set
Year set
Standing records
1956
10
1957
40
1958
20
1959
23
1960
20
1961
31
1962
47
1963
23
1964
49
1965
41
1966
27
1967
34
1968
28
1969
28
1970
17
1971
60
1972
16
1973
37
1974
14
1975
50
1976
24
1977
24
1978
17
1979
31
1980
20
1981
23
1982
12
1983
20
1984
10
1985
19
1986
33
1987
18
1988
24
1989
1
1992
17
1993
17
1994
12
1995
20
1996
26
1997
30
1998
41
1999
35
2000
41
2001
18
2002
13
2003
26
2004
20
2005
12
2006
18
2007
25
2008
97
2009
41
2010
21
2011
23
2012
20
All-Time Record Progression
4 new records
4 all-time records were set at San Isidro between 22 June 1998 and 23 July 2008. Each dot is a new record.
When San Isidro set new all-time records
Date
Kind
Detail
1998-06-22
Record high maximum temperature
Record high maximum temperature 50.6 C (123.1 F)
1998-07-09
Record high minimum temperature
Record high minimum temperature 30.6 C (87.1 F)
2008-07-01
Record high minimum temperature
Record high minimum temperature 32.8 C (91.0 F)
2008-07-23
Record high minimum temperature
Record high minimum temperature 35.6 C (96.1 F)
Wettest Day of Each Month
Sep: 143.5 mm (5.6 in)
The wettest day on record for each calendar month at San Isidro. The most was 143.5 mm (5.6 in) on 22 September 1976.
Record daily precipitation for each month at San Isidro
Month
Record daily precipitation (mm)
Date
Jan
56.9 mm (2.2 in)
19 January 1961
Feb
31.8 mm (1.3 in)
6 February 1992
Mar
46.2 mm (1.8 in)
2 March 1983
Apr
7.1 mm (0.28 in)
26 April 1985
May
27.2 mm (1.1 in)
29 May 1972
Jun
20.8 mm (0.8 in)
24 June 2006
Jul
74.9 mm (2.9 in)
29 July 1963
Aug
101.9 mm (4.0 in)
5 August 1959
Sep
143.5 mm (5.6 in)
22 September 1976
Oct
57.9 mm (2.3 in)
23 October 2006
Nov
65.3 mm (2.6 in)
11 November 1994
Dec
102.6 mm (4.0 in)
8 December 1988
Period of Record Coverage
1956 to 2012
Complete yearUnder 90 percent of days
55 years of record at San Isidro, 1956 to 2012. 8 years have data for under 90 percent of days and are left out of rankings: 1956, 1986, 1989, 1992, 1999, 2002, 2004, 2005.
Cooler than the station meanWarmer than the station mean
One stripe for each of 43 complete years at San Isidro, 1957 to 2011. Blue stripes are years cooler than the station's own mean of 22.2 C (71.9 F); red stripes are warmer. The coolest year was 1975, at 20.1 C (68.2 F), and the warmest was 2001, at 23.9 C (75.1 F). The strongest colour marks a difference of 2.1 C (3.8 F).
Annual mean temperature at San Isidro as warming stripes, 1957 to 2011
Year
Annual mean temperature
Difference from the station mean
1957
21.9 C
-0.26 C
1958
22.5 C
+0.34 C
1959
22.3 C
+0.09 C
1960
21.2 C
-0.96 C
1961
21.1 C
-1.12 C
1962
21.3 C
-0.86 C
1963
21.8 C
-0.35 C
1964
20.5 C
-1.72 C
1965
20.9 C
-1.28 C
1966
21.6 C
-0.57 C
1967
21.5 C
-0.65 C
1968
21.2 C
-0.96 C
1969
21.2 C
-0.97 C
1970
21.2 C
-1.02 C
1971
20.2 C
-1.96 C
1972
21.3 C
-0.87 C
1973
20.7 C
-1.53 C
1974
20.9 C
-1.32 C
1975
20.1 C
-2.09 C
1976
21.0 C
-1.21 C
1977
21.6 C
-0.58 C
1978
22.0 C
-0.17 C
1979
21.5 C
-0.67 C
1980
22.8 C
+0.62 C
1981
23.6 C
+1.43 C
1982
22.7 C
+0.50 C
1983
23.1 C
+0.95 C
1984
23.1 C
+0.89 C
1985
22.7 C
+0.53 C
1987
22.7 C
+0.50 C
1993
23.3 C
+1.12 C
1994
23.0 C
+0.84 C
1995
23.2 C
+0.97 C
1996
23.7 C
+1.50 C
1997
23.7 C
+1.54 C
1998
23.2 C
+1.01 C
2000
23.6 C
+1.38 C
2001
23.9 C
+1.76 C
2007
23.4 C
+1.25 C
2008
22.5 C
+0.34 C
2009
23.6 C
+1.43 C
2010
23.1 C
+0.93 C
2011
23.4 C
+1.20 C
The annual mean temperature here has risen by 0.5 C (0.4 to 0.7) per decade over 1957 to 2011. In Fahrenheit: 0.9 F (0.7 to 1.2) per decade. The slope is a straight line fitted to 43 complete years; the brackets give its 95 percent interval.
Fitted temperature trends per decade at San Isidro
Measure
Per decade (C)
Per decade (F)
Period
Complete years
Reading
Annual mean temperature
0.5 C (0.4 to 0.7) per decade
0.9 F (0.7 to 1.2) per decade
1957 to 2011
43
Rise
Mean daily maximum
0.6 C (0.4 to 0.8) per decade
1.1 F (0.7 to 1.5) per decade
1957 to 2011
43
Rise
Mean daily minimum
0.4 C (0.3 to 0.6) per decade
0.7 F (0.5 to 1.0) per decade
1957 to 2011
43
Rise
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
1956 to 2012
Yearly extremes at San Isidro: the record and the median year
Measure
Record
Year of the record
Median year
Years with a value
Hottest day (TXx)
50.6 C (123.1 F)
1998
45.0 C (113.0 F)
55
Coldest night (TNn)
-6.7 C (19.9 F)
1971
-1.1 C (30.0 F)
55
Wettest day (Rx1day)
143.5 mm (5.6 in)
1976
42.2 mm (1.7 in)
55
Wettest five days (Rx5day)
146.3 mm (5.8 in)
1976
54.1 mm (2.1 in)
55
Longest dry spell (CDD)
263 days
2010
149 days
55
Hottest day (TXx)
The hottest day of the year at San Isidro, 1956 to 2012. The record is 50.6 C (123.1 F) in 1998, marked on the chart; the median year is 45.0 C (113.0 F).
Hottest day (TXx) at San Isidro by year
Year
Hottest day (TXx)
1956
42.2 C (108.0 F)
1957
43.3 C (109.9 F)
1958
47.8 C (118.0 F)
1959
45.6 C (114.1 F)
1960
45.6 C (114.1 F)
1961
42.8 C (109.0 F)
1962
42.8 C (109.0 F)
1963
42.8 C (109.0 F)
1964
42.8 C (109.0 F)
1965
40.0 C (104.0 F)
1966
41.1 C (106.0 F)
1967
41.7 C (107.1 F)
1968
44.4 C (111.9 F)
1969
43.9 C (111.0 F)
1970
43.9 C (111.0 F)
1971
40.6 C (105.1 F)
1972
42.8 C (109.0 F)
1973
43.3 C (109.9 F)
1974
42.2 C (108.0 F)
1975
40.6 C (105.1 F)
1976
40.6 C (105.1 F)
1977
46.7 C (116.1 F)
1978
42.8 C (109.0 F)
1979
45.0 C (113.0 F)
1980
45.6 C (114.1 F)
1981
46.7 C (116.1 F)
1982
45.0 C (113.0 F)
1983
45.0 C (113.0 F)
1984
43.9 C (111.0 F)
1985
45.6 C (114.1 F)
1986
45.6 C (114.1 F)
1987
45.6 C (114.1 F)
1988
45.6 C (114.1 F)
1989
35.6 C (96.1 F)
1992
46.7 C (116.1 F)
1993
46.7 C (116.1 F)
1994
45.0 C (113.0 F)
1995
45.0 C (113.0 F)
1996
45.6 C (114.1 F)
1997
46.7 C (116.1 F)
1998
50.6 C (123.1 F)
1999
47.8 C (118.0 F)
2000
47.8 C (118.0 F)
2001
45.6 C (114.1 F)
2002
46.7 C (116.1 F)
2003
42.8 C (109.0 F)
2004
43.9 C (111.0 F)
2005
40.0 C (104.0 F)
2006
45.0 C (113.0 F)
2007
45.0 C (113.0 F)
2008
43.9 C (111.0 F)
2009
42.8 C (109.0 F)
2010
43.9 C (111.0 F)
2011
45.6 C (114.1 F)
2012
47.8 C (118.0 F)
Coldest night (TNn)
The coldest night of the year at San Isidro, 1956 to 2012. The record is -6.7 C (19.9 F) in 1971, marked on the chart; the median year is -1.1 C (30.0 F).
Coldest night (TNn) at San Isidro by year
Year
Coldest night (TNn)
1956
-1.7 C (28.9 F)
1957
0.6 C (33.1 F)
1958
-1.1 C (30.0 F)
1959
-1.1 C (30.0 F)
1960
-3.3 C (26.1 F)
1961
0.6 C (33.1 F)
1962
-3.9 C (25.0 F)
1963
-2.2 C (28.0 F)
1964
-4.4 C (24.1 F)
1965
-2.2 C (28.0 F)
1966
-2.8 C (27.0 F)
1967
-0.6 C (30.9 F)
1968
-2.8 C (27.0 F)
1969
0.0 C (32.0 F)
1970
-2.2 C (28.0 F)
1971
-6.7 C (19.9 F)
1972
-2.2 C (28.0 F)
1973
-2.8 C (27.0 F)
1974
-3.9 C (25.0 F)
1975
-2.2 C (28.0 F)
1976
-2.2 C (28.0 F)
1977
-2.2 C (28.0 F)
1978
-3.3 C (26.1 F)
1979
-1.1 C (30.0 F)
1980
0.0 C (32.0 F)
1981
0.0 C (32.0 F)
1982
0.0 C (32.0 F)
1983
1.7 C (35.1 F)
1984
0.6 C (33.1 F)
1985
-5.0 C (23.0 F)
1986
0.6 C (33.1 F)
1987
-4.4 C (24.1 F)
1988
-1.1 C (30.0 F)
1989
0.0 C (32.0 F)
1992
0.0 C (32.0 F)
1993
0.6 C (33.1 F)
1994
0.0 C (32.0 F)
1995
1.7 C (35.1 F)
1996
-1.1 C (30.0 F)
1997
-1.1 C (30.0 F)
1998
-1.1 C (30.0 F)
1999
0.0 C (32.0 F)
2000
-1.1 C (30.0 F)
2001
0.0 C (32.0 F)
2002
-3.3 C (26.1 F)
2003
0.6 C (33.1 F)
2004
1.7 C (35.1 F)
2005
0.6 C (33.1 F)
2006
0.0 C (32.0 F)
2007
-1.1 C (30.0 F)
2008
0.6 C (33.1 F)
2009
0.6 C (33.1 F)
2010
2.8 C (37.0 F)
2011
-1.1 C (30.0 F)
2012
2.8 C (37.0 F)
Wettest day (Rx1day)
The wettest day of the year at San Isidro, 1956 to 2012. The record is 143.5 mm (5.6 in) in 1976, marked on the chart; the median year is 42.2 mm (1.7 in).
Wettest day (Rx1day) at San Isidro by year
Year
Wettest day (Rx1day)
1956
11.9 mm (0.5 in)
1957
29.0 mm (1.1 in)
1958
77.0 mm (3.0 in)
1959
101.9 mm (4.0 in)
1960
54.9 mm (2.2 in)
1961
56.9 mm (2.2 in)
1962
50.8 mm (2.0 in)
1963
74.9 mm (2.9 in)
1964
83.8 mm (3.3 in)
1965
21.1 mm (0.8 in)
1966
45.7 mm (1.8 in)
1967
51.6 mm (2.0 in)
1968
57.7 mm (2.3 in)
1969
35.6 mm (1.4 in)
1970
52.1 mm (2.1 in)
1971
83.6 mm (3.3 in)
1972
31.0 mm (1.2 in)
1973
29.0 mm (1.1 in)
1974
24.9 mm (1.0 in)
1975
22.1 mm (0.9 in)
1976
143.5 mm (5.6 in)
1977
21.6 mm (0.9 in)
1978
25.9 mm (1.0 in)
1979
25.9 mm (1.0 in)
1980
24.9 mm (1.0 in)
1981
32.8 mm (1.3 in)
1982
65.8 mm (2.6 in)
1983
46.2 mm (1.8 in)
1984
20.1 mm (0.8 in)
1985
79.8 mm (3.1 in)
1986
79.8 mm (3.1 in)
1987
42.2 mm (1.7 in)
1988
102.6 mm (4.0 in)
1989
17.5 mm (0.7 in)
1992
78.0 mm (3.1 in)
1993
88.1 mm (3.5 in)
1994
97.3 mm (3.8 in)
1995
33.8 mm (1.3 in)
1996
45.0 mm (1.8 in)
1997
36.8 mm (1.4 in)
1998
47.8 mm (1.9 in)
1999
7.4 mm (0.29 in)
2000
17.8 mm (0.7 in)
2001
47.8 mm (1.9 in)
2002
34.3 mm (1.4 in)
2003
81.8 mm (3.2 in)
2004
53.8 mm (2.1 in)
2005
26.9 mm (1.1 in)
2006
57.9 mm (2.3 in)
2007
41.9 mm (1.6 in)
2008
35.8 mm (1.4 in)
2009
1.8 mm (0.07 in)
2010
2.3 mm (0.09 in)
2011
17.8 mm (0.7 in)
2012
16.0 mm (0.6 in)
Wettest five days (Rx5day)
The wettest five days of the year at San Isidro, 1956 to 2012. The record is 146.3 mm (5.8 in) in 1976, marked on the chart; the median year is 54.1 mm (2.1 in).
Wettest five days (Rx5day) at San Isidro by year
Year
Wettest five days (Rx5day)
1956
11.9 mm (0.5 in)
1957
30.3 mm (1.2 in)
1958
95.5 mm (3.8 in)
1959
131.9 mm (5.2 in)
1960
78.1 mm (3.1 in)
1961
67.6 mm (2.7 in)
1962
53.6 mm (2.1 in)
1963
82.0 mm (3.2 in)
1964
87.9 mm (3.5 in)
1965
31.6 mm (1.2 in)
1966
64.7 mm (2.5 in)
1967
55.2 mm (2.2 in)
1968
58.2 mm (2.3 in)
1969
54.1 mm (2.1 in)
1970
62.5 mm (2.5 in)
1971
92.5 mm (3.6 in)
1972
62.6 mm (2.5 in)
1973
30.5 mm (1.2 in)
1974
33.5 mm (1.3 in)
1975
22.1 mm (0.9 in)
1976
146.3 mm (5.8 in)
1977
28.0 mm (1.1 in)
1978
37.9 mm (1.5 in)
1979
33.3 mm (1.3 in)
1980
24.9 mm (1.0 in)
1981
37.9 mm (1.5 in)
1982
86.9 mm (3.4 in)
1983
51.8 mm (2.0 in)
1984
29.5 mm (1.2 in)
1985
79.8 mm (3.1 in)
1986
80.6 mm (3.2 in)
1987
60.0 mm (2.4 in)
1988
106.2 mm (4.2 in)
1989
22.1 mm (0.9 in)
1992
101.1 mm (4.0 in)
1993
88.1 mm (3.5 in)
1994
99.3 mm (3.9 in)
1995
33.8 mm (1.3 in)
1996
77.0 mm (3.0 in)
1997
36.8 mm (1.4 in)
1998
55.7 mm (2.2 in)
1999
10.6 mm (0.4 in)
2000
26.5 mm (1.0 in)
2001
60.5 mm (2.4 in)
2002
49.2 mm (1.9 in)
2003
86.1 mm (3.4 in)
2004
103.1 mm (4.1 in)
2005
26.9 mm (1.1 in)
2006
80.8 mm (3.2 in)
2007
42.7 mm (1.7 in)
2008
35.8 mm (1.4 in)
2009
1.8 mm (0.07 in)
2010
2.3 mm (0.09 in)
2011
26.9 mm (1.1 in)
2012
21.3 mm (0.8 in)
Longest dry spell (CDD)
The longest dry spell of the year at San Isidro, 1956 to 2012. The record is 263 days in 2010, marked on the chart; the median year is 149 days.
Longest dry spell (CDD) at San Isidro by year
Year
Longest dry spell (CDD)
1956
118 days
1957
106 days
1958
138 days
1959
153 days
1960
143 days
1961
158 days
1962
155 days
1963
193 days
1964
124 days
1965
125 days
1966
153 days
1967
199 days
1968
157 days
1969
191 days
1970
113 days
1971
189 days
1972
148 days
1973
135 days
1974
183 days
1975
156 days
1976
149 days
1977
167 days
1978
135 days
1979
77 days
1980
149 days
1981
122 days
1982
187 days
1983
104 days
1984
170 days
1985
80 days
1986
85 days
1987
150 days
1988
206 days
1989
56 days
1992
99 days
1993
50 days
1994
150 days
1995
149 days
1996
160 days
1997
227 days
1998
199 days
1999
90 days
2000
143 days
2001
91 days
2002
46 days
2003
75 days
2004
126 days
2005
84 days
2006
174 days
2007
118 days
2008
155 days
2009
185 days
2010
263 days
2011
180 days
2012
189 days
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
48 years, 1957 to 2012
A day with at least 44.1 mm (1.7 in) of rain is expected about once in 2 years. A day with at least 145.5 mm (5.7 in) of rain is expected about once in 100 years.
Rainfall return levels at San Isidro: the daily rain expected about once in a given number of years
Expected about once in
A day with at least
Note
2 years
44.1 mm (1.7 in)
5 years
70.8 mm (2.8 in)
10 years
88.7 mm (3.5 in)
25 years
111.4 mm (4.4 in)
50 years
128.5 mm (5.1 in)
Longer than the 48 years of record
100 years
145.5 mm (5.7 in)
Longer than the 48 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, 48 years of values from 1957 to 2012.
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: 143.5 mm (5.6 in) in 1976; 102.6 mm (4.0 in) in 1988; 101.9 mm (4.0 in) in 1959.
Station Changes
2 suspected
2 changes were suspected in the annual mean temperature of San Isidro, at 1971 and 1981. Each is measured against neighbouring stations.
Relative to 5 neighbouring stations, the station's annual mean temperature from 1971 ran 0.6 C (1.0 F) lower than in the years before (likely change).
Relative to 5 neighbouring stations, the station's annual mean temperature from 1981 ran 1.2 C (2.1 F) higher than in the years before (likely change).
Suspected changes in the annual mean temperature at San Isidro, against neighbouring stations
Year
Shift (C)
Shift (F)
Strength
Neighbours
1971
-0.6
-1.0
likely
5
1981
+1.2
+2.1
likely
5
Possible change at the station (a move, a new instrument or a new site); the record is kept as measured. A "likely" change has a larger test statistic than a "possible" one. Neither says why the station differs from its neighbours. How changes are found, and the largest ones.
Download the Data
Data for San Isidro standing records by year: CSV or JSON. Field meanings are on the data page.
Data for San Isidro 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.