San Diego de la Union Weather Records (MXN00011064)

Record envelope, standing records and threshold days for San Diego de la Union (MXN00011064), Mexico, with 97 years of record.

Key Facts for San Diego de la Union

San Diego de la Union (MXN00011064) is a weather station in Mexico at 21.45 latitude and -100.87 longitude, 2,070 m (6,791 ft) above sea level.
The station reports from 1902 to 1998, 97 years of record.
1,464 records set at San Diego de la Union still stand.
Records are tracked for tmax, tmin, prcp: an element needs 30 years of data to be eligible.
San Diego de la Union set a daily record low maximum temperature of 10.6 C (51.1 F) on 23 October 1998.

About the Station

Location: Mexico, 21.45 latitude, -100.87 longitude.
Elevation: 2,070 m (6,791 ft).
Period of record: 1902 to 1998, 97 years.
Eligible elements: tmax, tmin, prcp.

Daily Record Envelope and 2026

0 days at or beyond a record

The band shows the record high and record low for each calendar day at San Diego de la Union. 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 Diego de la Union, with 2026 drawn through them
Month	Highest record high	Lowest record low	2026 highest maximum	2026 lowest minimum
Jan	38.3 C (100.9 F)	-8.3 C (17.1 F)	n/a	n/a
Feb	40.0 C (104.0 F)	-6.1 C (21.0 F)	n/a	n/a
Mar	41.7 C (107.1 F)	-4.4 C (24.1 F)	n/a	n/a
Apr	44.4 C (111.9 F)	0.0 C (32.0 F)	n/a	n/a
May	40.0 C (104.0 F)	3.9 C (39.0 F)	n/a	n/a
Jun	45.0 C (113.0 F)	3.9 C (39.0 F)	n/a	n/a
Jul	40.0 C (104.0 F)	5.6 C (42.1 F)	n/a	n/a
Aug	38.9 C (102.0 F)	2.8 C (37.0 F)	n/a	n/a
Sep	35.0 C (95.0 F)	0.0 C (32.0 F)	n/a	n/a
Oct	37.8 C (100.0 F)	-3.3 C (26.1 F)	n/a	n/a
Nov	39.4 C (102.9 F)	-5.0 C (23.0 F)	n/a	n/a
Dec	36.7 C (98.1 F)	-10.0 C (14.0 F)	n/a	n/a

Which Years Hold Standing Records

1,464 standing records

1,464 records at San Diego de la Union still stand. 1954 holds the most, with 317.

Standing records at San Diego de la Union by the year they were set
Year set	Standing records
1903	10
1904	1
1905	3
1906	5
1907	9
1908	9
1909	13
1911	11
1912	6
1924	3
1925	16
1926	13
1927	4
1928	17
1929	2
1931	6
1932	9
1933	11
1934	7
1935	16
1936	7
1937	3
1938	10
1939	2
1940	13
1941	11
1942	9
1943	24
1944	24
1945	17
1946	17
1947	77
1948	20
1949	21
1950	5
1951	6
1952	7
1953	15
1954	317
1955	228
1956	13
1957	13
1958	11
1959	6
1960	8
1961	7
1962	3
1963	13
1964	4
1965	14
1966	18
1967	15
1968	16
1969	11
1970	14
1971	12
1972	7
1973	11
1974	15
1975	10
1976	23
1977	6
1978	7
1979	19
1980	6
1981	5
1982	12
1983	11
1984	13
1985	11
1986	8
1987	14
1988	7
1990	4
1991	12
1992	14
1993	11
1994	6
1996	8
1997	25
1998	17

All-Time Record Progression

5 new records

5 all-time records were set at San Diego de la Union between 2 June 1954 and 14 December 1997. Each dot is a new record.

When San Diego de la Union set new all-time records
Date	Kind	Detail
1954-06-02	Record high minimum temperature	Record high minimum temperature 23.9 C (75.0 F)
1957-06-21	Record daily precipitation	Record daily precipitation 126.0 mm (5.0 in)
1964-01-14	Record low minimum temperature	Record low minimum temperature -8.3 C (17.1 F)
1967-01-11	Record low maximum temperature	Record low maximum temperature 2.8 C (37.0 F)
1997-12-14	Record low minimum temperature	Record low minimum temperature -10.0 C (14.0 F)

Wettest Day of Each Month

Jun: 126.0 mm (5.0 in)

The wettest day on record for each calendar month at San Diego de la Union. The most was 126.0 mm (5.0 in) on 21 June 1957.

Record daily precipitation for each month at San Diego de la Union
Month	Record daily precipitation (mm)	Date
Jan	26.7 mm (1.1 in)	18 January 1911
Feb	30.0 mm (1.2 in)	20 February 1958
Mar	41.9 mm (1.6 in)	16 March 1935
Apr	41.9 mm (1.6 in)	23 April 1954
May	65.8 mm (2.6 in)	26 May 1961
Jun	126.0 mm (5.0 in)	21 June 1957
Jul	75.2 mm (3.0 in)	24 July 1910
Aug	68.8 mm (2.7 in)	3 August 1965
Sep	75.4 mm (3.0 in)	23 September 1913
Oct	54.9 mm (2.2 in)	6 October 1998
Nov	38.9 mm (1.5 in)	29 November 1907
Dec	37.3 mm (1.5 in)	3 December 1979

Period of Record Coverage

1924 to 1998

73 years of record at San Diego de la Union, 1924 to 1998. 12 years have data for under 90 percent of days and are left out of rankings: 1924, 1927, 1929, 1931, 1932, 1939, 1954, 1955 and others.

Days with data per year at San Diego de la Union
Year	Days with data	Share of year	Complete
1924	144	39%	No
1925	365	100%	Yes
1926	365	100%	Yes
1927	243	67%	No
1928	334	91%	Yes
1929	120	33%	No
1931	90	25%	No
1932	122	33%	No
1933	365	100%	Yes
1934	365	100%	Yes
1935	365	100%	Yes
1936	365	100%	Yes
1937	364	100%	Yes
1938	330	90%	Yes
1939	126	35%	No
1940	365	100%	Yes
1941	364	100%	Yes
1942	365	100%	Yes
1943	365	100%	Yes
1944	364	99%	Yes
1945	365	100%	Yes
1946	365	100%	Yes
1947	334	92%	Yes
1948	365	100%	Yes
1949	365	100%	Yes
1950	363	99%	Yes
1951	334	92%	Yes
1952	334	91%	Yes
1953	363	99%	Yes
1954	317	87%	No
1955	259	71%	No
1956	362	99%	Yes
1957	360	99%	Yes
1958	365	100%	Yes
1959	227	62%	No
1960	365	100%	Yes
1961	364	100%	Yes
1962	365	100%	Yes
1963	365	100%	Yes
1964	365	100%	Yes
1965	365	100%	Yes
1966	365	100%	Yes
1967	364	100%	Yes
1968	365	100%	Yes
1969	362	99%	Yes
1970	365	100%	Yes
1971	365	100%	Yes
1972	365	100%	Yes
1973	365	100%	Yes
1974	365	100%	Yes
1975	364	100%	Yes
1976	364	99%	Yes
1977	365	100%	Yes
1978	365	100%	Yes
1979	365	100%	Yes
1980	364	99%	Yes
1981	365	100%	Yes
1982	365	100%	Yes
1983	365	100%	Yes
1984	365	100%	Yes
1985	365	100%	Yes
1986	365	100%	Yes
1987	364	100%	Yes
1988	271	74%	No
1990	214	59%	No
1991	365	100%	Yes
1992	366	100%	Yes
1993	364	100%	Yes
1994	365	100%	Yes
1995	365	100%	Yes
1996	365	100%	Yes
1997	365	100%	Yes
1998	304	83%	No

Latest Records

Latest records at San Diego de la Union
Date	Station	Record	Value	Beat old record by	Old record stood	Significance
23 October 1998	San Diego de la Union, MX	daily low max	10.6 C (51.1 F)	5.5 C (9.9 F)	5 years	21 of 100 (Routine)
22 October 1998	San Diego de la Union, MX	daily low max (Tie)	15.0 C (59.0 F)	tie	24 years	3 of 100 (Routine)
12 October 1998	San Diego de la Union, MX	daily low max (Tie)	15.0 C (59.0 F)	tie	0 years	1 of 100 (Routine)
6 October 1998	San Diego de la Union, MX	monthly rain	54.9 mm (2.2 in)	2.1 mm (0.08 in)	12 years	24 of 100 (Routine)
2 October 1998	San Diego de la Union, MX	daily rain	30.5 mm (1.2 in)	7.6 mm (0.30 in)	12 years	20 of 100 (Routine)
6 September 1998	San Diego de la Union, MX	daily low max	17.8 C (64.0 F)	2.2 C (4.0 F)	72 years	34 of 100 (Routine)
5 September 1998	San Diego de la Union, MX	daily low max	18.3 C (64.9 F)	1.7 C (3.1 F)	73 years	34 of 100 (Routine)
25 August 1998	San Diego de la Union, MX	daily low max	16.7 C (62.1 F)	2.2 C (4.0 F)	24 years	21 of 100 (Routine)
24 August 1998	San Diego de la Union, MX	monthly low max	16.1 C (61.0 F)	0.6 C (1.1 F)	39 years	29 of 100 (Routine)
20 July 1998	San Diego de la Union, MX	daily low max	17.8 C (64.0 F)	3.3 C (5.9 F)	15 years	22 of 100 (Routine)
14 July 1998	San Diego de la Union, MX	daily high max (Tie)	30.6 C (87.1 F)	tie	55 years	5 of 100 (Routine)
23 May 1998	San Diego de la Union, MX	daily low min (Tie)	7.2 C (45.0 F)	tie	52 years	6 of 100 (Routine)
22 May 1998	San Diego de la Union, MX	daily low min (Tie)	6.7 C (44.1 F)	tie	56 years	6 of 100 (Routine)
18 May 1998	San Diego de la Union, MX	daily low min	5.6 C (42.1 F)	1.1 C (2.0 F)	28 years	21 of 100 (Routine)
2 May 1998	San Diego de la Union, MX	daily low min	6.1 C (43.0 F)	0.6 C (1.1 F)	72 years	32 of 100 (Routine)
21 April 1998	San Diego de la Union, MX	daily low max	20.0 C (68.0 F)	0.6 C (1.1 F)	4 years	9 of 100 (Routine)
11 April 1998	San Diego de la Union, MX	daily low min (Tie)	3.9 C (39.0 F)	tie	27 years	4 of 100 (Routine)
9 March 1998	San Diego de la Union, MX	daily low max	12.8 C (55.0 F)	2.2 C (4.0 F)	1 year	12 of 100 (Routine)
7 March 1998	San Diego de la Union, MX	daily low min (Tie)	0.0 C (32.0 F)	tie	11 years	3 of 100 (Routine)
22 February 1998	San Diego de la Union, MX	daily low min (Tie)	0.0 C (32.0 F)	tie	72 years	7 of 100 (Routine)

Climate Trend

56 complete years, 1925 to 1997

One stripe for each of 56 complete years at San Diego de la Union, 1925 to 1997. Blue stripes are years cooler than the station's own mean of 16.8 C (62.2 F); red stripes are warmer. The coolest year was 1992, at 15.1 C (59.2 F), and the warmest was 1941, at 18.8 C (65.8 F). The strongest colour marks a difference of 2.0 C (3.6 F).

Annual mean temperature at San Diego de la Union as warming stripes, 1925 to 1997
Year	Annual mean temperature	Difference from the station mean
1925	16.4 C	-0.40 C
1926	16.1 C	-0.73 C
1933	17.6 C	+0.76 C
1934	16.9 C	+0.07 C
1935	17.1 C	+0.32 C
1936	16.9 C	+0.06 C
1937	18.0 C	+1.17 C
1940	18.7 C	+1.92 C
1941	18.8 C	+1.97 C
1942	18.0 C	+1.20 C
1943	17.5 C	+0.71 C
1944	17.2 C	+0.44 C
1945	18.2 C	+1.42 C
1946	18.5 C	+1.72 C
1948	17.2 C	+0.44 C
1949	16.9 C	+0.07 C
1950	16.2 C	-0.65 C
1953	15.7 C	-1.10 C
1956	16.4 C	-0.45 C
1957	18.4 C	+1.57 C
1958	16.8 C	+0.00 C
1960	16.7 C	-0.08 C
1961	17.1 C	+0.28 C
1962	17.4 C	+0.61 C
1963	16.6 C	-0.18 C
1964	16.9 C	+0.11 C
1965	16.5 C	-0.34 C
1966	15.8 C	-1.04 C
1967	16.2 C	-0.64 C
1968	16.0 C	-0.76 C
1969	17.1 C	+0.28 C
1970	16.6 C	-0.23 C
1971	16.4 C	-0.39 C
1972	17.0 C	+0.15 C
1973	16.9 C	+0.12 C
1974	16.4 C	-0.43 C
1975	15.8 C	-0.99 C
1976	15.3 C	-1.47 C
1977	16.1 C	-0.75 C
1978	16.2 C	-0.59 C
1979	16.4 C	-0.44 C
1980	17.1 C	+0.27 C
1981	16.7 C	-0.15 C
1982	17.9 C	+1.06 C
1983	17.5 C	+0.68 C
1984	17.0 C	+0.24 C
1985	17.2 C	+0.42 C
1986	17.4 C	+0.64 C
1987	17.1 C	+0.32 C
1991	15.7 C	-1.06 C
1992	15.1 C	-1.71 C
1993	15.8 C	-0.99 C
1994	16.2 C	-0.60 C
1995	16.4 C	-0.39 C
1996	15.6 C	-1.18 C
1997	15.5 C	-1.31 C

The annual mean temperature here has fallen by 0.2 C (0.1 to 0.3) per decade over 1925 to 1997. In Fahrenheit: 0.4 F (0.2 to 0.5) per decade. The slope is a straight line fitted to 56 complete years; the brackets give its 95 percent interval.

Fitted temperature trends per decade at San Diego de la Union
Measure	Per decade (C)	Per decade (F)	Period	Complete years	Reading
Annual mean temperature	-0.2 C (-0.3 to -0.1) per decade	-0.4 F (-0.5 to -0.2) per decade	1925 to 1997	56	Fall
Mean daily maximum	-0.3 C (-0.4 to -0.1) per decade	-0.5 F (-0.8 to -0.1) per decade	1925 to 1997	56	Fall
Mean daily minimum	-0.14 C (-0.24 to -0.03) per decade	-0.2 F (-0.4 to -0.1) per decade	1925 to 1997	56	Fall

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

1902 to 1998

Yearly extremes at San Diego de la Union: the record and the median year
Measure	Record	Year of the record	Median year	Years with a value
Hottest day (TXx)	45.0 C (113.0 F)	1954	34.4 C (93.9 F)	73
Coldest night (TNn)	-10.0 C (14.0 F)	1997	-2.8 C (27.0 F)	86
Wettest day (Rx1day)	126.0 mm (5.0 in)	1957	37.5 mm (1.5 in)	86
Wettest five days (Rx5day)	226.4 mm (8.9 in)	1976	73.3 mm (2.9 in)	86
Longest dry spell (CDD)	151 days	1949	71 days	86

Hottest day (TXx)

The hottest day of the year at San Diego de la Union, 1902 to 1998. The record is 45.0 C (113.0 F) in 1954, marked on the chart; the median year is 34.4 C (93.9 F).

Hottest day (TXx) at San Diego de la Union by year
Year	Hottest day (TXx)
1902	n/a
1903	n/a
1904	n/a
1905	n/a
1906	n/a
1907	n/a
1908	n/a
1909	n/a
1910	n/a
1911	n/a
1912	n/a
1913	n/a
1914	n/a
1924	30.0 C (86.0 F)
1925	31.7 C (89.1 F)
1926	32.8 C (91.0 F)
1927	33.9 C (93.0 F)
1928	33.3 C (91.9 F)
1929	31.7 C (89.1 F)
1931	30.0 C (86.0 F)
1932	30.6 C (87.1 F)
1933	36.1 C (97.0 F)
1934	33.3 C (91.9 F)
1935	34.4 C (93.9 F)
1936	34.4 C (93.9 F)
1937	34.4 C (93.9 F)
1938	34.4 C (93.9 F)
1939	29.4 C (84.9 F)
1940	31.7 C (89.1 F)
1941	35.0 C (95.0 F)
1942	36.7 C (98.1 F)
1943	35.6 C (96.1 F)
1944	36.7 C (98.1 F)
1945	36.7 C (98.1 F)
1946	38.9 C (102.0 F)
1947	38.9 C (102.0 F)
1948	37.8 C (100.0 F)
1949	36.1 C (97.0 F)
1950	35.0 C (95.0 F)
1951	33.9 C (93.0 F)
1952	33.9 C (93.0 F)
1953	35.6 C (96.1 F)
1954	45.0 C (113.0 F)
1955	44.4 C (111.9 F)
1956	32.8 C (91.0 F)
1957	36.7 C (98.1 F)
1958	32.8 C (91.0 F)
1959	28.9 C (84.0 F)
1960	31.7 C (89.1 F)
1961	36.7 C (98.1 F)
1962	35.6 C (96.1 F)
1963	33.9 C (93.0 F)
1964	35.0 C (95.0 F)
1965	32.2 C (90.0 F)
1966	31.7 C (89.1 F)
1967	34.4 C (93.9 F)
1968	32.8 C (91.0 F)
1969	35.0 C (95.0 F)
1970	35.0 C (95.0 F)
1971	34.4 C (93.9 F)
1972	33.9 C (93.0 F)
1973	35.6 C (96.1 F)
1974	33.9 C (93.0 F)
1975	35.0 C (95.0 F)
1976	31.7 C (89.1 F)
1977	33.9 C (93.0 F)
1978	33.9 C (93.0 F)
1979	33.9 C (93.0 F)
1980	35.0 C (95.0 F)
1981	33.3 C (91.9 F)
1982	35.6 C (96.1 F)
1983	37.8 C (100.0 F)
1984	35.0 C (95.0 F)
1985	35.6 C (96.1 F)
1986	35.6 C (96.1 F)
1987	35.6 C (96.1 F)
1988	35.6 C (96.1 F)
1990	28.3 C (82.9 F)
1991	33.9 C (93.0 F)
1992	32.8 C (91.0 F)
1993	32.8 C (91.0 F)
1994	32.2 C (90.0 F)
1995	33.9 C (93.0 F)
1996	33.3 C (91.9 F)
1997	32.2 C (90.0 F)
1998	35.0 C (95.0 F)

Coldest night (TNn)

The coldest night of the year at San Diego de la Union, 1902 to 1998. The record is -10.0 C (14.0 F) in 1997, marked on the chart; the median year is -2.8 C (27.0 F).

Coldest night (TNn) at San Diego de la Union by year
Year	Coldest night (TNn)
1902	4.4 C (39.9 F)
1903	2.2 C (36.0 F)
1904	1.1 C (34.0 F)
1905	0.0 C (32.0 F)
1906	-5.0 C (23.0 F)
1907	0.6 C (33.1 F)
1908	2.8 C (37.0 F)
1909	0.6 C (33.1 F)
1910	0.6 C (33.1 F)
1911	0.0 C (32.0 F)
1912	0.0 C (32.0 F)
1913	3.9 C (39.0 F)
1914	2.8 C (37.0 F)
1924	0.0 C (32.0 F)
1925	-3.9 C (25.0 F)
1926	-2.8 C (27.0 F)
1927	-3.9 C (25.0 F)
1928	-2.2 C (28.0 F)
1929	-1.7 C (28.9 F)
1931	-1.7 C (28.9 F)
1932	-5.0 C (23.0 F)
1933	-3.3 C (26.1 F)
1934	0.0 C (32.0 F)
1935	0.0 C (32.0 F)
1936	0.0 C (32.0 F)
1937	0.0 C (32.0 F)
1938	-6.1 C (21.0 F)
1939	0.0 C (32.0 F)
1940	-4.4 C (24.1 F)
1941	-4.4 C (24.1 F)
1942	-4.4 C (24.1 F)
1943	-3.3 C (26.1 F)
1944	-5.0 C (23.0 F)
1945	0.0 C (32.0 F)
1946	-2.2 C (28.0 F)
1947	-0.6 C (30.9 F)
1948	-0.6 C (30.9 F)
1949	-5.0 C (23.0 F)
1950	-2.8 C (27.0 F)
1951	-2.8 C (27.0 F)
1952	0.0 C (32.0 F)
1953	0.0 C (32.0 F)
1954	0.0 C (32.0 F)
1955	-6.1 C (21.0 F)
1956	-5.0 C (23.0 F)
1957	0.0 C (32.0 F)
1958	0.0 C (32.0 F)
1959	0.0 C (32.0 F)
1960	0.0 C (32.0 F)
1961	-0.6 C (30.9 F)
1962	0.0 C (32.0 F)
1963	-3.3 C (26.1 F)
1964	-8.3 C (17.1 F)
1965	-2.2 C (28.0 F)
1966	-3.3 C (26.1 F)
1967	-3.3 C (26.1 F)
1968	-1.7 C (28.9 F)
1969	-2.2 C (28.0 F)
1970	-4.4 C (24.1 F)
1971	0.0 C (32.0 F)
1972	-1.7 C (28.9 F)
1973	-4.4 C (24.1 F)
1974	-4.4 C (24.1 F)
1975	-5.0 C (23.0 F)
1976	-6.1 C (21.0 F)
1977	-4.4 C (24.1 F)
1978	-2.2 C (28.0 F)
1979	-4.4 C (24.1 F)
1980	-3.3 C (26.1 F)
1981	-5.0 C (23.0 F)
1982	-4.4 C (24.1 F)
1983	-5.0 C (23.0 F)
1984	-3.9 C (25.0 F)
1985	-5.0 C (23.0 F)
1986	-5.0 C (23.0 F)
1987	-5.0 C (23.0 F)
1988	-6.1 C (21.0 F)
1990	-5.0 C (23.0 F)
1991	-3.3 C (26.1 F)
1992	-3.3 C (26.1 F)
1993	-2.8 C (27.0 F)
1994	-3.3 C (26.1 F)
1995	-1.7 C (28.9 F)
1996	-0.6 C (30.9 F)
1997	-10.0 C (14.0 F)
1998	-5.0 C (23.0 F)

Wettest day (Rx1day)

The wettest day of the year at San Diego de la Union, 1902 to 1998. The record is 126.0 mm (5.0 in) in 1957, marked on the chart; the median year is 37.5 mm (1.5 in).

Wettest day (Rx1day) at San Diego de la Union by year
Year	Wettest day (Rx1day)
1902	47.5 mm (1.9 in)
1903	40.9 mm (1.6 in)
1904	54.9 mm (2.2 in)
1905	49.8 mm (2.0 in)
1906	41.7 mm (1.6 in)
1907	49.8 mm (2.0 in)
1908	30.0 mm (1.2 in)
1909	31.2 mm (1.2 in)
1910	75.2 mm (3.0 in)
1911	39.9 mm (1.6 in)
1912	37.1 mm (1.5 in)
1913	75.4 mm (3.0 in)
1914	8.9 mm (0.35 in)
1924	40.9 mm (1.6 in)
1925	34.3 mm (1.4 in)
1926	47.8 mm (1.9 in)
1927	28.4 mm (1.1 in)
1928	50.3 mm (2.0 in)
1929	0.0 mm (0.00 in)
1931	21.6 mm (0.9 in)
1932	22.1 mm (0.9 in)
1933	41.9 mm (1.6 in)
1934	37.8 mm (1.5 in)
1935	41.9 mm (1.6 in)
1936	30.7 mm (1.2 in)
1937	27.9 mm (1.1 in)
1938	15.0 mm (0.6 in)
1939	5.3 mm (0.21 in)
1940	7.4 mm (0.29 in)
1941	22.9 mm (0.9 in)
1942	15.5 mm (0.6 in)
1943	17.8 mm (0.7 in)
1944	14.5 mm (0.6 in)
1945	11.9 mm (0.5 in)
1946	9.4 mm (0.37 in)
1947	31.8 mm (1.3 in)
1948	35.8 mm (1.4 in)
1949	29.5 mm (1.2 in)
1950	50.3 mm (2.0 in)
1951	34.8 mm (1.4 in)
1952	30.0 mm (1.2 in)
1953	56.9 mm (2.2 in)
1954	41.9 mm (1.6 in)
1955	37.8 mm (1.5 in)
1956	31.8 mm (1.3 in)
1957	126.0 mm (5.0 in)
1958	69.9 mm (2.8 in)
1959	36.8 mm (1.4 in)
1960	59.9 mm (2.4 in)
1961	65.8 mm (2.6 in)
1962	23.4 mm (0.9 in)
1963	45.7 mm (1.8 in)
1964	44.5 mm (1.8 in)
1965	68.8 mm (2.7 in)
1966	33.3 mm (1.3 in)
1967	31.5 mm (1.2 in)
1968	74.9 mm (2.9 in)
1969	31.5 mm (1.2 in)
1970	37.6 mm (1.5 in)
1971	52.3 mm (2.1 in)
1972	29.0 mm (1.1 in)
1973	50.8 mm (2.0 in)
1974	48.3 mm (1.9 in)
1975	39.9 mm (1.6 in)
1976	69.9 mm (2.8 in)
1977	33.5 mm (1.3 in)
1978	52.3 mm (2.1 in)
1979	37.3 mm (1.5 in)
1980	30.0 mm (1.2 in)
1981	49.8 mm (2.0 in)
1982	56.4 mm (2.2 in)
1983	30.5 mm (1.2 in)
1984	37.8 mm (1.5 in)
1985	57.9 mm (2.3 in)
1986	52.8 mm (2.1 in)
1987	28.4 mm (1.1 in)
1988	46.0 mm (1.8 in)
1990	36.6 mm (1.4 in)
1991	57.9 mm (2.3 in)
1992	32.3 mm (1.3 in)
1993	26.4 mm (1.0 in)
1994	37.3 mm (1.5 in)
1995	31.5 mm (1.2 in)
1996	33.8 mm (1.3 in)
1997	39.4 mm (1.6 in)
1998	54.9 mm (2.2 in)

Wettest five days (Rx5day)

The wettest five days of the year at San Diego de la Union, 1902 to 1998. The record is 226.4 mm (8.9 in) in 1976, marked on the chart; the median year is 73.3 mm (2.9 in).

Wettest five days (Rx5day) at San Diego de la Union by year
Year	Wettest five days (Rx5day)
1902	73.9 mm (2.9 in)
1903	68.3 mm (2.7 in)
1904	81.0 mm (3.2 in)
1905	99.6 mm (3.9 in)
1906	78.1 mm (3.1 in)
1907	74.7 mm (2.9 in)
1908	42.7 mm (1.7 in)
1909	45.4 mm (1.8 in)
1910	109.8 mm (4.3 in)
1911	96.9 mm (3.8 in)
1912	49.8 mm (2.0 in)
1913	118.9 mm (4.7 in)
1914	8.9 mm (0.35 in)
1924	61.8 mm (2.4 in)
1925	80.2 mm (3.2 in)
1926	131.1 mm (5.2 in)
1927	41.2 mm (1.6 in)
1928	113.8 mm (4.5 in)
1929	0.0 mm (0.00 in)
1931	40.4 mm (1.6 in)
1932	37.1 mm (1.5 in)
1933	68.4 mm (2.7 in)
1934	99.6 mm (3.9 in)
1935	73.4 mm (2.9 in)
1936	48.4 mm (1.9 in)
1937	90.4 mm (3.6 in)
1938	35.9 mm (1.4 in)
1939	13.2 mm (0.5 in)
1940	10.7 mm (0.4 in)
1941	76.2 mm (3.0 in)
1942	56.2 mm (2.2 in)
1943	35.6 mm (1.4 in)
1944	45.0 mm (1.8 in)
1945	42.4 mm (1.7 in)
1946	34.7 mm (1.4 in)
1947	91.8 mm (3.6 in)
1948	81.1 mm (3.2 in)
1949	53.9 mm (2.1 in)
1950	101.4 mm (4.0 in)
1951	44.4 mm (1.7 in)
1952	66.0 mm (2.6 in)
1953	166.4 mm (6.6 in)
1954	47.7 mm (1.9 in)
1955	41.1 mm (1.6 in)
1956	55.4 mm (2.2 in)
1957	126.0 mm (5.0 in)
1958	130.4 mm (5.1 in)
1959	39.1 mm (1.5 in)
1960	83.6 mm (3.3 in)
1961	100.1 mm (3.9 in)
1962	44.5 mm (1.8 in)
1963	132.0 mm (5.2 in)
1964	65.1 mm (2.6 in)
1965	86.3 mm (3.4 in)
1966	82.6 mm (3.3 in)
1967	61.9 mm (2.4 in)
1968	121.9 mm (4.8 in)
1969	72.1 mm (2.8 in)
1970	98.1 mm (3.9 in)
1971	132.2 mm (5.2 in)
1972	52.6 mm (2.1 in)
1973	128.3 mm (5.1 in)
1974	52.7 mm (2.1 in)
1975	105.0 mm (4.1 in)
1976	226.4 mm (8.9 in)
1977	77.3 mm (3.0 in)
1978	74.5 mm (2.9 in)
1979	65.8 mm (2.6 in)
1980	60.5 mm (2.4 in)
1981	98.0 mm (3.9 in)
1982	84.6 mm (3.3 in)
1983	55.5 mm (2.2 in)
1984	80.2 mm (3.2 in)
1985	95.0 mm (3.7 in)
1986	103.1 mm (4.1 in)
1987	55.9 mm (2.2 in)
1988	105.6 mm (4.2 in)
1990	53.9 mm (2.1 in)
1991	90.4 mm (3.6 in)
1992	57.2 mm (2.3 in)
1993	55.7 mm (2.2 in)
1994	54.1 mm (2.1 in)
1995	73.1 mm (2.9 in)
1996	86.9 mm (3.4 in)
1997	69.9 mm (2.8 in)
1998	85.4 mm (3.4 in)

Longest dry spell (CDD)

The longest dry spell of the year at San Diego de la Union, 1902 to 1998. The record is 151 days in 1949, marked on the chart; the median year is 71 days.

Longest dry spell (CDD) at San Diego de la Union by year
Year	Longest dry spell (CDD)
1902	65 days
1903	83 days
1904	59 days
1905	43 days
1906	30 days
1907	58 days
1908	91 days
1909	121 days
1910	91 days
1911	60 days
1912	83 days
1913	32 days
1914	69 days
1924	55 days
1925	54 days
1926	68 days
1927	83 days
1928	57 days
1929	120 days
1931	32 days
1932	61 days
1933	103 days
1934	68 days
1935	47 days
1936	50 days
1937	79 days
1938	69 days
1939	78 days
1940	60 days
1941	60 days
1942	87 days
1943	144 days
1944	67 days
1945	85 days
1946	86 days
1947	112 days
1948	81 days
1949	151 days
1950	148 days
1951	117 days
1952	101 days
1953	87 days
1954	79 days
1955	120 days
1956	128 days
1957	95 days
1958	70 days
1959	64 days
1960	80 days
1961	119 days
1962	71 days
1963	78 days
1964	35 days
1965	45 days
1966	50 days
1967	46 days
1968	41 days
1969	91 days
1970	82 days
1971	75 days
1972	46 days
1973	62 days
1974	37 days
1975	97 days
1976	59 days
1977	80 days
1978	78 days
1979	70 days
1980	34 days
1981	36 days
1982	45 days
1983	73 days
1984	60 days
1985	48 days
1986	70 days
1987	74 days
1988	68 days
1990	38 days
1991	88 days
1992	36 days
1993	82 days
1994	83 days
1995	140 days
1996	128 days
1997	51 days
1998	101 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.

Frost Dates and Growing Season

45 years with a frost

Across 45 years with a frost, the median last spring frost at San Diego de la Union falls on 26 February and the median first autumn frost on 21 November, which leaves a median of 264 days between them.

Fitted over all years, the growing season changes by -0.8 days per decade at this station.

Frost dates and growing season at San Diego de la Union
Measure	Median, all years	Earliest period	Recent period (1956 to 1997)	Recent against earliest	Fitted trend
Last spring frost	26 February	n/a	27 February	n/a	-0.1 days per decade
First autumn frost	21 November	n/a	20 November	n/a	-0.9 days per decade
Growing days	264 days	n/a	262 days	n/a	-0.8 days per decade

A frost day is a day with a daily minimum at or below 0 C (32 F). The last spring frost and the first autumn frost are the last and first such days of the cold season, and growing days are the days between them. A negative trend for the last spring frost means it comes earlier.

Rainfall Return Levels

73 years, 1903 to 1997

A day with at least 38.2 mm (1.5 in) of rain is expected about once in 2 years. A day with at least 92.3 mm (3.6 in) of rain is expected about once in 100 years.

Rainfall return levels at San Diego de la Union: the daily rain expected about once in a given number of years
Expected about once in	A day with at least	Note
2 years	38.2 mm (1.5 in)
5 years	54.1 mm (2.1 in)
10 years	64.1 mm (2.5 in)
25 years	76.0 mm (3.0 in)
50 years	84.4 mm (3.3 in)
100 years	92.3 mm (3.6 in)	Longer than the 73 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, 73 years of values from 1903 to 1997.

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: 126.0 mm (5.0 in) in 1957; 75.2 mm (3.0 in) in 1910; 74.9 mm (2.9 in) in 1968.

Station Changes

1 suspected

One change was suspected in the annual mean temperature of San Diego de la Union, at 1982. Each is measured against neighbouring stations.

Relative to 5 neighbouring stations, the station's annual mean temperature from 1982 ran 0.6 C (1.1 F) higher than in the years before (possible change).

Suspected changes in the annual mean temperature at San Diego de la Union, against neighbouring stations
Year	Shift (C)	Shift (F)	Strength	Neighbours
1982	+0.6	+1.1	possible	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 Diego de la Union standing records by year: CSV or JSON. Field meanings are on the data page.
Data for San Diego de la Union 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 2025-12-31. Last revised 31 December 2025 (2025-12-31).