San Miguel El Alto Weather Records (MXN00014131)

Record envelope, standing records and threshold days for San Miguel El Alto (MXN00014131), Mexico, with 61 years of record.

Key Facts for San Miguel El Alto

San Miguel El Alto (MXN00014131) is a weather station in Mexico at 21.02 latitude and -102.40 longitude, 1,850 m (6,069 ft) above sea level.
The station reports from 1939 to 1999, 61 years of record.
1,464 records set at San Miguel El Alto still stand.
Records are tracked for tmax, tmin, prcp: an element needs 30 years of data to be eligible.
San Miguel El Alto tied a daily record low minimum temperature of -5.0 C (23.0 F) on 22 December 1999.

About the Station

Location: Mexico, 21.02 latitude, -102.40 longitude.
Elevation: 1,850 m (6,069 ft).
Period of record: 1939 to 1999, 61 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 Miguel El Alto. 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 Miguel El Alto, 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)	-9.4 C (15.1 F)	n/a	n/a
Feb	41.1 C (106.0 F)	-7.8 C (18.0 F)	n/a	n/a
Mar	41.1 C (106.0 F)	-5.0 C (23.0 F)	n/a	n/a
Apr	42.8 C (109.0 F)	-1.1 C (30.0 F)	n/a	n/a
May	41.7 C (107.1 F)	1.1 C (34.0 F)	n/a	n/a
Jun	40.0 C (104.0 F)	5.0 C (41.0 F)	n/a	n/a
Jul	35.6 C (96.1 F)	8.3 C (46.9 F)	n/a	n/a
Aug	35.6 C (96.1 F)	5.6 C (42.1 F)	n/a	n/a
Sep	35.6 C (96.1 F)	1.7 C (35.1 F)	n/a	n/a
Oct	35.6 C (96.1 F)	-4.4 C (24.1 F)	n/a	n/a
Nov	35.6 C (96.1 F)	-7.2 C (19.0 F)	n/a	n/a
Dec	39.4 C (102.9 F)	-13.3 C (8.1 F)	n/a	n/a

Which Years Hold Standing Records

1,464 standing records

1,464 records at San Miguel El Alto still stand. 1939 holds the most, with 189.

Standing records at San Miguel El Alto by the year they were set
Year set	Standing records
1939	189
1940	37
1941	22
1942	73
1943	183
1944	22
1945	10
1946	14
1947	14
1948	10
1949	16
1950	22
1951	23
1952	49
1953	29
1954	10
1955	17
1956	13
1957	38
1958	31
1959	27
1960	4
1961	26
1962	13
1963	11
1964	16
1965	11
1966	5
1967	11
1968	15
1969	23
1970	15
1971	8
1972	12
1973	12
1974	15
1975	6
1976	18
1977	4
1978	7
1979	25
1980	16
1981	10
1982	10
1983	12
1984	8
1985	19
1986	19
1987	23
1988	15
1989	17
1990	13
1991	15
1992	4
1993	15
1994	5
1995	11
1996	9
1997	97
1998	14
1999	26

All-Time Record Progression

1 new records

1 all-time records were set at San Miguel El Alto between 14 December 1997 and 14 December 1997. Each dot is a new record.

Wettest Day of Each Month

Jul: 104.9 mm (4.1 in)

The wettest day on record for each calendar month at San Miguel El Alto. The most was 104.9 mm (4.1 in) on 2 July 1944.

Record daily precipitation for each month at San Miguel El Alto
Month	Record daily precipitation (mm)	Date
Jan	33.3 mm (1.3 in)	6 January 1964
Feb	33.3 mm (1.3 in)	17 February 1968
Mar	29.0 mm (1.1 in)	26 March 1953
Apr	31.8 mm (1.3 in)	17 April 1968
May	54.9 mm (2.2 in)	27 May 1972
Jun	88.4 mm (3.5 in)	23 June 1993
Jul	104.9 mm (4.1 in)	2 July 1944
Aug	62.0 mm (2.4 in)	5 August 1988
Sep	71.9 mm (2.8 in)	12 September 1982
Oct	61.5 mm (2.4 in)	1 October 1978
Nov	36.3 mm (1.4 in)	26 November 1982
Dec	25.4 mm (1.0 in)	12 December 1963

Period of Record Coverage

1939 to 1999

60 years of record at San Miguel El Alto, 1939 to 1999. 12 years have data for under 90 percent of days and are left out of rankings: 1939, 1941, 1956, 1960, 1961, 1962, 1966, 1967 and others.

Days with data per year at San Miguel El Alto
Year	Days with data	Share of year	Complete
1939	209	57%	No
1941	179	49%	No
1942	347	95%	Yes
1943	334	92%	Yes
1944	336	92%	Yes
1945	345	95%	Yes
1946	338	93%	Yes
1947	341	93%	Yes
1948	351	96%	Yes
1949	354	97%	Yes
1950	364	100%	Yes
1951	362	99%	Yes
1952	364	99%	Yes
1953	359	98%	Yes
1954	365	100%	Yes
1955	359	98%	Yes
1956	315	86%	No
1957	360	99%	Yes
1958	353	97%	Yes
1959	354	97%	Yes
1960	90	25%	No
1961	325	89%	No
1962	271	74%	No
1963	359	98%	Yes
1964	332	91%	Yes
1965	334	92%	Yes
1966	207	57%	No
1967	181	50%	No
1968	332	91%	Yes
1969	298	82%	No
1970	351	96%	Yes
1971	362	99%	Yes
1972	355	97%	Yes
1973	297	81%	No
1974	360	99%	Yes
1975	362	99%	Yes
1976	361	99%	Yes
1977	363	99%	Yes
1978	365	100%	Yes
1979	364	100%	Yes
1980	360	98%	Yes
1981	356	98%	Yes
1982	357	98%	Yes
1983	356	98%	Yes
1984	357	98%	Yes
1985	359	98%	Yes
1986	357	98%	Yes
1987	359	98%	Yes
1988	363	99%	Yes
1989	363	99%	Yes
1990	359	98%	Yes
1991	265	73%	No
1992	122	33%	No
1993	359	98%	Yes
1994	362	99%	Yes
1995	361	99%	Yes
1996	360	98%	Yes
1997	360	99%	Yes
1998	350	96%	Yes
1999	331	91%	Yes

Latest Records

Latest records at San Miguel El Alto
Date	Station	Record	Value	Beat old record by	Old record stood	Significance
22 December 1999	San Miguel El Alto, MX	daily low min (Tie)	-5.0 C (23.0 F)	tie	26 years	3 of 100 (Routine)
16 December 1999	San Miguel El Alto, MX	daily low min (Tie)	-3.3 C (26.1 F)	tie	29 years	3 of 100 (Routine)
13 December 1999	San Miguel El Alto, MX	daily low min	-4.4 C (24.1 F)	1.1 C (2.0 F)	45 years	22 of 100 (Routine)
7 December 1999	San Miguel El Alto, MX	daily low min	-5.0 C (23.0 F)	1.7 C (3.1 F)	12 years	13 of 100 (Routine)
4 December 1999	San Miguel El Alto, MX	daily low min	-4.4 C (24.1 F)	1.1 C (2.0 F)	12 years	12 of 100 (Routine)
2 December 1999	San Miguel El Alto, MX	daily low min (Tie)	-3.3 C (26.1 F)	tie	48 years	5 of 100 (Routine)
21 November 1999	San Miguel El Alto, MX	daily low min	-2.2 C (28.0 F)	0.5 C (0.9 F)	29 years	15 of 100 (Routine)
20 November 1999	San Miguel El Alto, MX	daily low min	-3.3 C (26.1 F)	1.1 C (2.0 F)	49 years	22 of 100 (Routine)
18 November 1999	San Miguel El Alto, MX	daily low min (Tie)	-2.2 C (28.0 F)	tie	49 years	5 of 100 (Routine)
3 November 1999	San Miguel El Alto, MX	daily low min	-3.3 C (26.1 F)	3.3 C (5.9 F)	10 years	17 of 100 (Routine)
2 November 1999	San Miguel El Alto, MX	daily low min	-4.4 C (24.1 F)	4.4 C (7.9 F)	10 years	20 of 100 (Routine)
31 October 1999	San Miguel El Alto, MX	daily low min (Tie)	-1.1 C (30.0 F)	tie	12 years	2 of 100 (Routine)
29 October 1999	San Miguel El Alto, MX	daily low min	-3.3 C (26.1 F)	3.9 C (7.0 F)	48 years	30 of 100 (Routine)
28 October 1999	San Miguel El Alto, MX	monthly low min (Tie)	-4.4 C (24.1 F)	tie	0 years	4 of 100 (Routine)
27 October 1999	San Miguel El Alto, MX	daily low min	-3.3 C (26.1 F)	3.3 C (5.9 F)	48 years	29 of 100 (Routine)
26 October 1999	San Miguel El Alto, MX	daily low min	-2.2 C (28.0 F)	3.3 C (5.9 F)	48 years	29 of 100 (Routine)
25 October 1999	San Miguel El Alto, MX	monthly low min	-4.4 C (24.1 F)	1.1 C (2.0 F)	0 years	19 of 100 (Routine)
24 October 1999	San Miguel El Alto, MX	monthly low min	-3.3 C (26.1 F)	1.6 C (2.9 F)	48 years	34 of 100 (Routine)
23 October 1999	San Miguel El Alto, MX	daily low min	-1.1 C (30.0 F)	1.7 C (3.1 F)	54 years	26 of 100 (Routine)
17 October 1999	San Miguel El Alto, MX	daily high max (Tie)	28.9 C (84.0 F)	tie	57 years	5 of 100 (Routine)

Climate Trend

44 complete years, 1942 to 1998

One stripe for each of 44 complete years at San Miguel El Alto, 1942 to 1998. Blue stripes are years cooler than the station's own mean of 17.5 C (63.5 F); red stripes are warmer. The coolest year was 1958, at 16.2 C (61.2 F), and the warmest was 1997, at 20.4 C (68.6 F). The strongest colour marks a difference of 2.9 C (5.2 F).

Annual mean temperature at San Miguel El Alto as warming stripes, 1942 to 1998
Year	Annual mean temperature	Difference from the station mean
1942	19.6 C	+2.12 C
1943	19.2 C	+1.71 C
1944	16.7 C	-0.84 C
1945	17.5 C	+0.00 C
1946	17.4 C	-0.11 C
1947	17.3 C	-0.17 C
1948	17.6 C	+0.10 C
1949	17.1 C	-0.37 C
1950	16.7 C	-0.83 C
1951	17.0 C	-0.48 C
1952	18.2 C	+0.73 C
1953	17.7 C	+0.23 C
1954	18.0 C	+0.50 C
1955	17.4 C	-0.10 C
1957	17.7 C	+0.18 C
1958	16.2 C	-1.30 C
1959	16.6 C	-0.92 C
1963	16.8 C	-0.66 C
1970	16.8 C	-0.69 C
1971	17.0 C	-0.51 C
1972	17.5 C	+0.00 C
1974	16.7 C	-0.79 C
1975	17.0 C	-0.54 C
1976	17.3 C	-0.24 C
1977	17.6 C	+0.14 C
1978	17.5 C	-0.02 C
1979	17.3 C	-0.22 C
1980	17.4 C	-0.09 C
1981	17.1 C	-0.36 C
1982	17.7 C	+0.24 C
1983	16.8 C	-0.75 C
1984	17.0 C	-0.47 C
1985	17.2 C	-0.26 C
1986	16.9 C	-0.61 C
1987	16.9 C	-0.65 C
1988	17.0 C	-0.52 C
1989	17.3 C	-0.18 C
1990	17.5 C	-0.05 C
1993	17.0 C	-0.50 C
1994	18.7 C	+1.17 C
1995	18.7 C	+1.17 C
1996	19.0 C	+1.53 C
1997	20.4 C	+2.86 C
1998	17.9 C	+0.40 C

The fitted trend in annual mean temperature here over 1942 to 1998 is 0.05 C (-0.10 to 0.19) per decade. The interval includes zero, so the trend is not clearly different from zero. In Fahrenheit: 0.1 F (-0.2 to 0.3) per decade. The slope is a straight line fitted to 44 complete years; the brackets give its 95 percent interval.

Fitted temperature trends per decade at San Miguel El Alto
Measure	Per decade (C)	Per decade (F)	Period	Complete years	Reading
Annual mean temperature	0.05 C (-0.10 to 0.19) per decade	0.1 F (-0.2 to 0.3) per decade	1942 to 1998	44	Not clearly different from zero
Mean daily maximum	0.22 C (-0.03 to 0.47) per decade	0.4 F (-0.1 to 0.8) per decade	1942 to 1998	44	Not clearly different from zero
Mean daily minimum	-0.12 C (-0.24 to 0.00) per decade	-0.22 F (-0.44 to -0.01) per decade	1942 to 1998	44	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

1939 to 1999

Yearly extremes at San Miguel El Alto: the record and the median year
Measure	Record	Year of the record	Median year	Years with a value
Hottest day (TXx)	42.8 C (109.0 F)	1943	34.2 C (93.5 F)	60
Coldest night (TNn)	-13.3 C (8.1 F)	1997	-4.4 C (24.1 F)	61
Wettest day (Rx1day)	104.9 mm (4.1 in)	1944	48.8 mm (1.9 in)	61
Wettest five days (Rx5day)	236.5 mm (9.3 in)	1976	92.8 mm (3.7 in)	61
Longest dry spell (CDD)	157 days	1998	83 days	61

Hottest day (TXx)

The hottest day of the year at San Miguel El Alto, 1939 to 1999. The record is 42.8 C (109.0 F) in 1943, marked on the chart; the median year is 34.2 C (93.5 F).

Hottest day (TXx) at San Miguel El Alto by year
Year	Hottest day (TXx)
1939	36.7 C (98.1 F)
1940	n/a
1941	38.9 C (102.0 F)
1942	39.4 C (102.9 F)
1943	42.8 C (109.0 F)
1944	32.8 C (91.0 F)
1945	33.9 C (93.0 F)
1946	33.9 C (93.0 F)
1947	32.8 C (91.0 F)
1948	33.3 C (91.9 F)
1949	33.9 C (93.0 F)
1950	35.6 C (96.1 F)
1951	33.3 C (91.9 F)
1952	34.4 C (93.9 F)
1953	35.6 C (96.1 F)
1954	35.0 C (95.0 F)
1955	37.2 C (99.0 F)
1956	32.8 C (91.0 F)
1957	33.9 C (93.0 F)
1958	30.0 C (86.0 F)
1959	30.6 C (87.1 F)
1960	26.7 C (80.1 F)
1961	35.6 C (96.1 F)
1962	35.6 C (96.1 F)
1963	32.8 C (91.0 F)
1964	36.7 C (98.1 F)
1965	33.9 C (93.0 F)
1966	31.7 C (89.1 F)
1967	31.7 C (89.1 F)
1968	33.9 C (93.0 F)
1969	33.3 C (91.9 F)
1970	33.9 C (93.0 F)
1971	31.7 C (89.1 F)
1972	35.6 C (96.1 F)
1973	32.8 C (91.0 F)
1974	31.7 C (89.1 F)
1975	33.9 C (93.0 F)
1976	33.3 C (91.9 F)
1977	33.9 C (93.0 F)
1978	35.0 C (95.0 F)
1979	32.8 C (91.0 F)
1980	33.9 C (93.0 F)
1981	34.4 C (93.9 F)
1982	35.0 C (95.0 F)
1983	35.6 C (96.1 F)
1984	32.8 C (91.0 F)
1985	36.7 C (98.1 F)
1986	35.0 C (95.0 F)
1987	32.8 C (91.0 F)
1988	35.0 C (95.0 F)
1989	35.6 C (96.1 F)
1990	36.7 C (98.1 F)
1991	35.0 C (95.0 F)
1992	28.9 C (84.0 F)
1993	36.7 C (98.1 F)
1994	35.6 C (96.1 F)
1995	36.7 C (98.1 F)
1996	35.0 C (95.0 F)
1997	37.8 C (100.0 F)
1998	36.7 C (98.1 F)
1999	37.8 C (100.0 F)

Coldest night (TNn)

The coldest night of the year at San Miguel El Alto, 1939 to 1999. The record is -13.3 C (8.1 F) in 1997, marked on the chart; the median year is -4.4 C (24.1 F).

Coldest night (TNn) at San Miguel El Alto by year
Year	Coldest night (TNn)
1939	10.0 C (50.0 F)
1940	16.7 C (62.1 F)
1941	3.9 C (39.0 F)
1942	-1.1 C (30.0 F)
1943	-6.1 C (21.0 F)
1944	-6.1 C (21.0 F)
1945	-6.7 C (19.9 F)
1946	-4.4 C (24.1 F)
1947	-2.2 C (28.0 F)
1948	-1.1 C (30.0 F)
1949	-6.1 C (21.0 F)
1950	-6.1 C (21.0 F)
1951	-7.8 C (18.0 F)
1952	-3.3 C (26.1 F)
1953	-5.6 C (21.9 F)
1954	-2.2 C (28.0 F)
1955	-7.8 C (18.0 F)
1956	-5.0 C (23.0 F)
1957	-4.4 C (24.1 F)
1958	-4.4 C (24.1 F)
1959	0.0 C (32.0 F)
1960	-2.2 C (28.0 F)
1961	-2.2 C (28.0 F)
1962	-3.3 C (26.1 F)
1963	-4.4 C (24.1 F)
1964	-3.3 C (26.1 F)
1965	-3.3 C (26.1 F)
1966	-7.2 C (19.0 F)
1967	-9.4 C (15.1 F)
1968	-4.4 C (24.1 F)
1969	-3.3 C (26.1 F)
1970	-5.0 C (23.0 F)
1971	-3.3 C (26.1 F)
1972	-5.0 C (23.0 F)
1973	-6.1 C (21.0 F)
1974	-3.3 C (26.1 F)
1975	-6.1 C (21.0 F)
1976	-6.1 C (21.0 F)
1977	0.6 C (33.1 F)
1978	-2.2 C (28.0 F)
1979	-7.2 C (19.0 F)
1980	-5.0 C (23.0 F)
1981	-5.0 C (23.0 F)
1982	-3.3 C (26.1 F)
1983	-5.6 C (21.9 F)
1984	-2.2 C (28.0 F)
1985	-7.2 C (19.0 F)
1986	-5.6 C (21.9 F)
1987	-6.1 C (21.0 F)
1988	-7.2 C (19.0 F)
1989	-6.1 C (21.0 F)
1990	-5.0 C (23.0 F)
1991	-5.0 C (23.0 F)
1992	-1.1 C (30.0 F)
1993	-3.9 C (25.0 F)
1994	-2.2 C (28.0 F)
1995	-4.4 C (24.1 F)
1996	-3.3 C (26.1 F)
1997	-13.3 C (8.1 F)
1998	-7.2 C (19.0 F)
1999	-6.1 C (21.0 F)

Wettest day (Rx1day)

The wettest day of the year at San Miguel El Alto, 1939 to 1999. The record is 104.9 mm (4.1 in) in 1944, marked on the chart; the median year is 48.8 mm (1.9 in).

Wettest day (Rx1day) at San Miguel El Alto by year
Year	Wettest day (Rx1day)
1939	9.9 mm (0.39 in)
1940	2.8 mm (0.11 in)
1941	40.6 mm (1.6 in)
1942	71.9 mm (2.8 in)
1943	30.5 mm (1.2 in)
1944	104.9 mm (4.1 in)
1945	54.9 mm (2.2 in)
1946	50.8 mm (2.0 in)
1947	57.9 mm (2.3 in)
1948	52.8 mm (2.1 in)
1949	48.3 mm (1.9 in)
1950	50.8 mm (2.0 in)
1951	49.3 mm (1.9 in)
1952	47.0 mm (1.9 in)
1953	35.8 mm (1.4 in)
1954	50.3 mm (2.0 in)
1955	50.8 mm (2.0 in)
1956	44.5 mm (1.8 in)
1957	40.9 mm (1.6 in)
1958	30.0 mm (1.2 in)
1959	59.9 mm (2.4 in)
1960	0.0 mm (0.00 in)
1961	36.8 mm (1.4 in)
1962	47.2 mm (1.9 in)
1963	45.7 mm (1.8 in)
1964	46.0 mm (1.8 in)
1965	72.6 mm (2.9 in)
1966	43.9 mm (1.7 in)
1967	56.9 mm (2.2 in)
1968	43.2 mm (1.7 in)
1969	39.9 mm (1.6 in)
1970	59.9 mm (2.4 in)
1971	56.4 mm (2.2 in)
1972	59.9 mm (2.4 in)
1973	47.8 mm (1.9 in)
1974	25.4 mm (1.0 in)
1975	33.8 mm (1.3 in)
1976	74.9 mm (2.9 in)
1977	34.3 mm (1.4 in)
1978	61.5 mm (2.4 in)
1979	67.6 mm (2.7 in)
1980	48.8 mm (1.9 in)
1981	51.6 mm (2.0 in)
1982	71.9 mm (2.8 in)
1983	49.8 mm (2.0 in)
1984	38.9 mm (1.5 in)
1985	38.4 mm (1.5 in)
1986	61.0 mm (2.4 in)
1987	43.9 mm (1.7 in)
1988	64.8 mm (2.6 in)
1989	63.8 mm (2.5 in)
1990	48.8 mm (1.9 in)
1991	63.8 mm (2.5 in)
1992	15.0 mm (0.6 in)
1993	88.4 mm (3.5 in)
1994	38.9 mm (1.5 in)
1995	56.9 mm (2.2 in)
1996	55.9 mm (2.2 in)
1997	36.8 mm (1.4 in)
1998	52.8 mm (2.1 in)
1999	35.8 mm (1.4 in)

Wettest five days (Rx5day)

The wettest five days of the year at San Miguel El Alto, 1939 to 1999. The record is 236.5 mm (9.3 in) in 1976, marked on the chart; the median year is 92.8 mm (3.7 in).

Wettest five days (Rx5day) at San Miguel El Alto by year
Year	Wettest five days (Rx5day)
1939	28.0 mm (1.1 in)
1940	3.6 mm (0.14 in)
1941	90.4 mm (3.6 in)
1942	140.7 mm (5.5 in)
1943	77.7 mm (3.1 in)
1944	141.0 mm (5.6 in)
1945	83.0 mm (3.3 in)
1946	97.5 mm (3.8 in)
1947	122.0 mm (4.8 in)
1948	80.4 mm (3.2 in)
1949	103.7 mm (4.1 in)
1950	120.5 mm (4.7 in)
1951	113.2 mm (4.5 in)
1952	112.8 mm (4.4 in)
1953	85.4 mm (3.4 in)
1954	126.0 mm (5.0 in)
1955	99.1 mm (3.9 in)
1956	117.2 mm (4.6 in)
1957	70.1 mm (2.8 in)
1958	61.2 mm (2.4 in)
1959	107.1 mm (4.2 in)
1960	0.0 mm (0.00 in)
1961	71.9 mm (2.8 in)
1962	82.8 mm (3.3 in)
1963	90.0 mm (3.5 in)
1964	70.9 mm (2.8 in)
1965	204.7 mm (8.1 in)
1966	60.2 mm (2.4 in)
1967	133.1 mm (5.2 in)
1968	92.8 mm (3.7 in)
1969	79.4 mm (3.1 in)
1970	121.4 mm (4.8 in)
1971	88.6 mm (3.5 in)
1972	113.0 mm (4.4 in)
1973	126.9 mm (5.0 in)
1974	53.2 mm (2.1 in)
1975	77.4 mm (3.0 in)
1976	236.5 mm (9.3 in)
1977	98.8 mm (3.9 in)
1978	95.6 mm (3.8 in)
1979	124.2 mm (4.9 in)
1980	80.2 mm (3.2 in)
1981	87.4 mm (3.4 in)
1982	99.1 mm (3.9 in)
1983	101.7 mm (4.0 in)
1984	81.7 mm (3.2 in)
1985	81.8 mm (3.2 in)
1986	117.1 mm (4.6 in)
1987	68.8 mm (2.7 in)
1988	128.0 mm (5.0 in)
1989	120.2 mm (4.7 in)
1990	97.5 mm (3.8 in)
1991	124.4 mm (4.9 in)
1992	41.6 mm (1.6 in)
1993	173.2 mm (6.8 in)
1994	63.9 mm (2.5 in)
1995	87.4 mm (3.4 in)
1996	81.6 mm (3.2 in)
1997	91.4 mm (3.6 in)
1998	85.0 mm (3.3 in)
1999	106.4 mm (4.2 in)

Longest dry spell (CDD)

The longest dry spell of the year at San Miguel El Alto, 1939 to 1999. The record is 157 days in 1998, marked on the chart; the median year is 83 days.

Longest dry spell (CDD) at San Miguel El Alto by year
Year	Longest dry spell (CDD)
1939	55 days
1940	20 days
1941	32 days
1942	99 days
1943	150 days
1944	83 days
1945	79 days
1946	54 days
1947	103 days
1948	52 days
1949	69 days
1950	144 days
1951	75 days
1952	54 days
1953	84 days
1954	79 days
1955	119 days
1956	73 days
1957	70 days
1958	85 days
1959	94 days
1960	91 days
1961	107 days
1962	54 days
1963	58 days
1964	44 days
1965	66 days
1966	28 days
1967	47 days
1968	50 days
1969	90 days
1970	104 days
1971	132 days
1972	76 days
1973	130 days
1974	66 days
1975	117 days
1976	92 days
1977	99 days
1978	92 days
1979	104 days
1980	55 days
1981	51 days
1982	54 days
1983	126 days
1984	92 days
1985	64 days
1986	104 days
1987	79 days
1988	65 days
1989	128 days
1990	75 days
1991	152 days
1992	29 days
1993	101 days
1994	87 days
1995	103 days
1996	113 days
1997	79 days
1998	157 days
1999	87 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

35 years with a frost

Across 35 years with a frost, the median last spring frost at San Miguel El Alto falls on 25 February and the median first autumn frost on 13 November, which leaves a median of 273 days between them.

Fitted over all years, the growing season changes by -0.3 days per decade at this station.

Frost dates and growing season at San Miguel El Alto
Measure	Median, all years	Earliest period	Recent period (1947 to 1998)	Recent against earliest	Fitted trend
Last spring frost	25 February	n/a	23 February	n/a	+1.1 days per decade
First autumn frost	13 November	n/a	14 November	n/a	+0.7 days per decade
Growing days	273 days	n/a	267 days	n/a	-0.3 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

50 years, 1942 to 1999

A day with at least 49.9 mm (2.0 in) of rain is expected about once in 2 years. A day with at least 96.3 mm (3.8 in) of rain is expected about once in 100 years.

Rainfall return levels at San Miguel El Alto: the daily rain expected about once in a given number of years
Expected about once in	A day with at least	Note
2 years	49.9 mm (2.0 in)
5 years	63.3 mm (2.5 in)
10 years	71.8 mm (2.8 in)
25 years	82.0 mm (3.2 in)
50 years	89.3 mm (3.5 in)
100 years	96.3 mm (3.8 in)	Longer than the 50 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, 50 years of values from 1942 to 1999.

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: 104.9 mm (4.1 in) in 1944; 88.4 mm (3.5 in) in 1993; 74.9 mm (2.9 in) in 1976.

Download the Data

Data for San Miguel El Alto standing records by year: CSV or JSON. Field meanings are on the data page.
Data for San Miguel El Alto 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). Records are computed by this site and are not official.

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