Zacualtipan (Smn) Weather Records (MXN00013042)

Record envelope, standing records and threshold days for Zacualtipan (Smn) (MXN00013042), Mexico, with 72 years of record.

Key Facts for Zacualtipan (Smn)

Zacualtipan (Smn) (MXN00013042) is a weather station in Mexico at 20.63 latitude and -98.65 longitude, 1,988 m (6,522 ft) above sea level.
The station reports from 1941 to 2012, 72 years of record.
1,464 records set at Zacualtipan (Smn) still stand.
Records are tracked for tmax, tmin, prcp: an element needs 30 years of data to be eligible.
Zacualtipan (Smn) set a daily record low minimum temperature of 0.0 C (32.0 F) on 6 October 2012.

About the Station

Location: Mexico, 20.63 latitude, -98.65 longitude.
Elevation: 1,988 m (6,522 ft).
Period of record: 1941 to 2012, 72 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 Zacualtipan (Smn). 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 Zacualtipan (Smn), with 2026 drawn through them
Month	Highest record high	Lowest record low	2026 highest maximum	2026 lowest minimum
Jan	30.6 C (87.1 F)	-10.0 C (14.0 F)	n/a	n/a
Feb	32.8 C (91.0 F)	-10.0 C (14.0 F)	n/a	n/a
Mar	36.7 C (98.1 F)	-10.0 C (14.0 F)	n/a	n/a
Apr	37.8 C (100.0 F)	-5.0 C (23.0 F)	n/a	n/a
May	37.2 C (99.0 F)	-2.2 C (28.0 F)	n/a	n/a
Jun	37.8 C (100.0 F)	-2.2 C (28.0 F)	n/a	n/a
Jul	33.9 C (93.0 F)	0.0 C (32.0 F)	n/a	n/a
Aug	30.6 C (87.1 F)	0.0 C (32.0 F)	n/a	n/a
Sep	31.7 C (89.1 F)	-5.0 C (23.0 F)	n/a	n/a
Oct	30.6 C (87.1 F)	-5.0 C (23.0 F)	n/a	n/a
Nov	31.7 C (89.1 F)	-8.3 C (17.1 F)	n/a	n/a
Dec	30.0 C (86.0 F)	-10.0 C (14.0 F)	n/a	n/a

Which Years Hold Standing Records

1,464 standing records

1,464 records at Zacualtipan (Smn) still stand. 1943 holds the most, with 135.

Standing records at Zacualtipan (Smn) by the year they were set
Year set	Standing records
1941	50
1942	123
1943	135
1944	35
1945	28
1946	35
1947	43
1948	23
1949	1
1950	2
1951	7
1952	5
1953	10
1954	4
1955	15
1956	2
1957	16
1958	9
1959	8
1960	9
1961	2
1962	3
1963	26
1964	51
1965	71
1966	57
1967	27
1968	52
1969	36
1970	32
1971	32
1972	16
1973	27
1974	32
1975	22
1976	37
1977	6
1978	8
1979	11
1980	14
1981	12
1982	5
1983	5
1984	7
1985	5
1986	5
1987	15
1988	5
1989	11
1990	9
1991	10
1992	12
1993	10
1994	13
1995	28
1996	11
1997	16
1998	16
1999	7
2000	6
2001	20
2002	25
2003	23
2004	7
2005	10
2006	7
2007	1
2008	6
2009	6
2010	10
2011	17
2012	2

All-Time Record Progression

1 new records

1 all-time records were set at Zacualtipan (Smn) between 13 December 1997 and 13 December 1997. Each dot is a new record.

Wettest Day of Each Month

Oct: 348.5 mm (13.7 in)

The wettest day on record for each calendar month at Zacualtipan (Smn). The most was 348.5 mm (13.7 in) on 7 October 1954.

Record daily precipitation for each month at Zacualtipan (Smn)
Month	Record daily precipitation (mm)	Date
Jan	63.8 mm (2.5 in)	3 January 1956
Feb	34.8 mm (1.4 in)	10 February 1946
Mar	59.9 mm (2.4 in)	30 March 1950
Apr	81.8 mm (3.2 in)	4 April 1950
May	85.3 mm (3.4 in)	28 May 1984
Jun	112.8 mm (4.4 in)	29 June 2011
Jul	126.5 mm (5.0 in)	10 July 1955
Aug	199.9 mm (7.9 in)	22 August 2007
Sep	279.9 mm (11.0 in)	20 September 1974
Oct	348.5 mm (13.7 in)	7 October 1954
Nov	71.4 mm (2.8 in)	9 November 1971
Dec	52.1 mm (2.1 in)	4 December 1981

Period of Record Coverage

1941 to 2012

72 years of record at Zacualtipan (Smn), 1941 to 2012. 4 years have data for under 90 percent of days and are left out of rankings: 1941, 1942, 1944, 2012.

Days with data per year at Zacualtipan (Smn)
Year	Days with data	Share of year	Complete
1941	75	21%	No
1942	271	74%	No
1943	359	98%	Yes
1944	328	90%	No
1945	365	100%	Yes
1946	365	100%	Yes
1947	363	99%	Yes
1948	365	100%	Yes
1949	335	92%	Yes
1950	365	100%	Yes
1951	365	100%	Yes
1952	354	97%	Yes
1953	365	100%	Yes
1954	334	92%	Yes
1955	365	100%	Yes
1956	360	98%	Yes
1957	365	100%	Yes
1958	365	100%	Yes
1959	365	100%	Yes
1960	366	100%	Yes
1961	365	100%	Yes
1962	365	100%	Yes
1963	365	100%	Yes
1964	366	100%	Yes
1965	365	100%	Yes
1966	365	100%	Yes
1967	365	100%	Yes
1968	366	100%	Yes
1969	347	95%	Yes
1970	365	100%	Yes
1971	364	100%	Yes
1972	366	100%	Yes
1973	364	100%	Yes
1974	364	100%	Yes
1975	365	100%	Yes
1976	366	100%	Yes
1977	363	99%	Yes
1978	363	99%	Yes
1979	357	98%	Yes
1980	365	100%	Yes
1981	363	99%	Yes
1982	365	100%	Yes
1983	364	100%	Yes
1984	365	100%	Yes
1985	363	99%	Yes
1986	364	100%	Yes
1987	331	91%	Yes
1988	366	100%	Yes
1989	333	91%	Yes
1990	363	99%	Yes
1991	358	98%	Yes
1992	361	99%	Yes
1993	361	99%	Yes
1994	333	91%	Yes
1995	363	99%	Yes
1996	365	100%	Yes
1997	362	99%	Yes
1998	363	99%	Yes
1999	362	99%	Yes
2000	365	100%	Yes
2001	365	100%	Yes
2002	362	99%	Yes
2003	333	91%	Yes
2004	334	91%	Yes
2005	364	100%	Yes
2006	364	100%	Yes
2007	364	100%	Yes
2008	365	100%	Yes
2009	364	100%	Yes
2010	365	100%	Yes
2011	334	92%	Yes
2012	153	42%	No

Latest Records

Latest records at Zacualtipan (Smn)
Date	Station	Record	Value	Beat old record by	Old record stood	Significance
6 October 2012	Zacualtipan (Smn), MX	daily low min	0.0 C (32.0 F)	0.6 C (1.1 F)	55 years	24 of 100 (Routine)
10 August 2012	Zacualtipan (Smn), MX	daily rain	74.9 mm (2.9 in)	39.1 mm (1.5 in)	47 years	45 of 100 (Notable)
10 August 2012	Zacualtipan (Smn), MX	daily low max	13.9 C (57.0 F)	1.1 C (2.0 F)	47 years	24 of 100 (Routine)
9 August 2012	Zacualtipan (Smn), MX	daily low max (Tie)	15.0 C (59.0 F)	tie	12 years	2 of 100 (Routine)
29 November 2011	Zacualtipan (Smn), MX	daily low min (Tie)	-5.0 C (23.0 F)	tie	37 years	4 of 100 (Routine)
26 November 2011	Zacualtipan (Smn), MX	daily rain	16.8 mm (0.7 in)	7.4 mm (0.29 in)	1 year	13 of 100 (Routine)
17 November 2011	Zacualtipan (Smn), MX	daily rain	31.0 mm (1.2 in)	3.1 mm (0.12 in)	52 years	24 of 100 (Routine)
14 August 2011	Zacualtipan (Smn), MX	daily high max	28.9 C (84.0 F)	1.1 C (2.0 F)	66 years	30 of 100 (Routine)
13 August 2011	Zacualtipan (Smn), MX	daily high max (Tie)	27.8 C (82.0 F)	tie	66 years	6 of 100 (Routine)
12 August 2011	Zacualtipan (Smn), MX	daily high max	27.8 C (82.0 F)	1.1 C (2.0 F)	65 years	29 of 100 (Routine)
11 August 2011	Zacualtipan (Smn), MX	daily high max	27.8 C (82.0 F)	1.1 C (2.0 F)	8 years	12 of 100 (Routine)
10 August 2011	Zacualtipan (Smn), MX	daily high max (Tie)	27.8 C (82.0 F)	tie	64 years	6 of 100 (Routine)
5 August 2011	Zacualtipan (Smn), MX	daily low max	13.9 C (57.0 F)	0.5 C (0.9 F)	32 years	17 of 100 (Routine)
4 August 2011	Zacualtipan (Smn), MX	daily low max	12.8 C (55.0 F)	2.2 C (4.0 F)	40 years	25 of 100 (Routine)
3 August 2011	Zacualtipan (Smn), MX	daily low max	15.0 C (59.0 F)	0.6 C (1.1 F)	41 years	20 of 100 (Routine)
2 August 2011	Zacualtipan (Smn), MX	monthly low max (Tie)	11.7 C (53.1 F)	tie	0 years	4 of 100 (Routine)
1 August 2011	Zacualtipan (Smn), MX	monthly low max (Tie)	11.7 C (53.1 F)	tie	0 years	4 of 100 (Routine)
31 July 2011	Zacualtipan (Smn), MX	daily low max	11.7 C (53.1 F)	3.9 C (7.0 F)	42 years	30 of 100 (Routine)
30 July 2011	Zacualtipan (Smn), MX	daily low max	15.0 C (59.0 F)	0.6 C (1.1 F)	42 years	20 of 100 (Routine)
20 July 2011	Zacualtipan (Smn), MX	daily low max (Tie)	15.0 C (59.0 F)	tie	46 years	5 of 100 (Routine)

Climate Trend

59 complete years, 1943 to 2010

One stripe for each of 59 complete years at Zacualtipan (Smn), 1943 to 2010. Blue stripes are years cooler than the station's own mean of 13.0 C (55.4 F); red stripes are warmer. The coolest year was 1966, at 8.9 C (48.1 F), and the warmest was 1943, at 17.9 C (64.1 F). The strongest colour marks a difference of 4.9 C (8.8 F).

Annual mean temperature at Zacualtipan (Smn) as warming stripes, 1943 to 2010
Year	Annual mean temperature	Difference from the station mean
1943	17.9 C	+4.88 C
1945	15.6 C	+2.64 C
1946	14.9 C	+1.97 C
1947	14.5 C	+1.49 C
1948	15.9 C	+2.91 C
1950	14.1 C	+1.11 C
1951	12.7 C	-0.26 C
1953	12.5 C	-0.48 C
1955	12.3 C	-0.72 C
1956	12.1 C	-0.86 C
1957	12.8 C	-0.16 C
1958	12.7 C	-0.29 C
1959	12.6 C	-0.35 C
1960	13.3 C	+0.36 C
1961	12.2 C	-0.81 C
1962	12.6 C	-0.37 C
1963	12.2 C	-0.79 C
1964	10.9 C	-2.05 C
1965	10.2 C	-2.76 C
1966	8.9 C	-4.03 C
1967	10.5 C	-2.51 C
1968	9.0 C	-4.02 C
1969	9.9 C	-3.10 C
1970	9.9 C	-3.12 C
1971	9.8 C	-3.18 C
1972	10.6 C	-2.33 C
1973	10.4 C	-2.56 C
1974	9.9 C	-3.04 C
1975	10.0 C	-3.00 C
1976	9.5 C	-3.47 C
1977	13.0 C	0.00 C
1978	13.6 C	+0.63 C
1979	13.4 C	+0.39 C
1980	13.2 C	+0.18 C
1981	13.2 C	+0.22 C
1982	13.3 C	+0.32 C
1983	13.4 C	+0.38 C
1984	13.4 C	+0.47 C
1985	13.6 C	+0.67 C
1986	13.5 C	+0.54 C
1988	13.6 C	+0.58 C
1990	13.3 C	+0.36 C
1991	14.0 C	+1.04 C
1992	13.1 C	+0.08 C
1993	13.5 C	+0.51 C
1995	16.3 C	+3.30 C
1996	14.9 C	+1.92 C
1997	14.7 C	+1.72 C
1998	15.3 C	+2.34 C
1999	14.5 C	+1.56 C
2000	14.6 C	+1.61 C
2001	15.2 C	+2.24 C
2002	15.8 C	+2.81 C
2005	14.2 C	+1.19 C
2006	14.4 C	+1.47 C
2007	14.1 C	+1.10 C
2008	13.7 C	+0.74 C
2009	13.7 C	+0.73 C
2010	12.9 C	-0.06 C

The fitted trend in annual mean temperature here over 1943 to 2010 is 0.22 C (-0.04 to 0.49) per decade. The interval includes zero, so the trend is not clearly different from zero. In Fahrenheit: 0.4 F (-0.1 to 0.9) per decade. The slope is a straight line fitted to 59 complete years; the brackets give its 95 percent interval.

Fitted temperature trends per decade at Zacualtipan (Smn)
Measure	Per decade (C)	Per decade (F)	Period	Complete years	Reading
Annual mean temperature	0.22 C (-0.04 to 0.49) per decade	0.4 F (-0.1 to 0.9) per decade	1943 to 2010	59	Not clearly different from zero
Mean daily maximum	-0.2 C (-0.5 to 0.1) per decade	-0.3 F (-0.9 to 0.2) per decade	1943 to 2010	59	Not clearly different from zero
Mean daily minimum	0.6 C (0.3 to 0.9) per decade	1.1 F (0.6 to 1.6) per decade	1943 to 2010	59	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

1941 to 2012

Yearly extremes at Zacualtipan (Smn): the record and the median year
Measure	Record	Year of the record	Median year	Years with a value
Hottest day (TXx)	37.8 C (100.0 F)	1944	31.7 C (89.1 F)	72
Coldest night (TNn)	-10.0 C (14.0 F)	1963	-4.4 C (24.1 F)	72
Wettest day (Rx1day)	348.5 mm (13.7 in)	1954	83.8 mm (3.3 in)	72
Wettest five days (Rx5day)	835.2 mm (32.9 in)	1954	190.8 mm (7.5 in)	72
Longest dry spell (CDD)	75 days	1948	26 days	72

Hottest day (TXx)

The hottest day of the year at Zacualtipan (Smn), 1941 to 2012. The record is 37.8 C (100.0 F) in 1944, marked on the chart; the median year is 31.7 C (89.1 F).

Hottest day (TXx) at Zacualtipan (Smn) by year
Year	Hottest day (TXx)
1941	27.8 C (82.0 F)
1942	36.7 C (98.1 F)
1943	35.0 C (95.0 F)
1944	37.8 C (100.0 F)
1945	35.0 C (95.0 F)
1946	32.8 C (91.0 F)
1947	31.7 C (89.1 F)
1948	35.0 C (95.0 F)
1949	30.6 C (87.1 F)
1950	33.9 C (93.0 F)
1951	35.0 C (95.0 F)
1952	30.6 C (87.1 F)
1953	35.0 C (95.0 F)
1954	32.2 C (90.0 F)
1955	37.2 C (99.0 F)
1956	30.0 C (86.0 F)
1957	35.0 C (95.0 F)
1958	35.6 C (96.1 F)
1959	30.0 C (86.0 F)
1960	35.6 C (96.1 F)
1961	35.0 C (95.0 F)
1962	31.7 C (89.1 F)
1963	37.8 C (100.0 F)
1964	35.0 C (95.0 F)
1965	30.0 C (86.0 F)
1966	27.8 C (82.0 F)
1967	30.0 C (86.0 F)
1968	26.7 C (80.1 F)
1969	30.6 C (87.1 F)
1970	30.6 C (87.1 F)
1971	31.7 C (89.1 F)
1972	30.0 C (86.0 F)
1973	35.0 C (95.0 F)
1974	31.7 C (89.1 F)
1975	30.0 C (86.0 F)
1976	28.9 C (84.0 F)
1977	31.7 C (89.1 F)
1978	31.1 C (88.0 F)
1979	30.6 C (87.1 F)
1980	30.0 C (86.0 F)
1981	31.1 C (88.0 F)
1982	30.0 C (86.0 F)
1983	32.8 C (91.0 F)
1984	35.6 C (96.1 F)
1985	30.0 C (86.0 F)
1986	32.8 C (91.0 F)
1987	30.0 C (86.0 F)
1988	30.0 C (86.0 F)
1989	30.6 C (87.1 F)
1990	30.0 C (86.0 F)
1991	31.7 C (89.1 F)
1992	27.8 C (82.0 F)
1993	30.0 C (86.0 F)
1994	33.3 C (91.9 F)
1995	35.0 C (95.0 F)
1996	35.0 C (95.0 F)
1997	31.7 C (89.1 F)
1998	36.7 C (98.1 F)
1999	32.8 C (91.0 F)
2000	32.8 C (91.0 F)
2001	33.9 C (93.0 F)
2002	35.0 C (95.0 F)
2003	36.7 C (98.1 F)
2004	32.8 C (91.0 F)
2005	35.0 C (95.0 F)
2006	32.8 C (91.0 F)
2007	31.7 C (89.1 F)
2008	32.8 C (91.0 F)
2009	31.7 C (89.1 F)
2010	33.9 C (93.0 F)
2011	31.7 C (89.1 F)
2012	28.9 C (84.0 F)

Coldest night (TNn)

The coldest night of the year at Zacualtipan (Smn), 1941 to 2012. The record is -10.0 C (14.0 F) in 1963, marked on the chart; the median year is -4.4 C (24.1 F).

Coldest night (TNn) at Zacualtipan (Smn) by year
Year	Coldest night (TNn)
1941	3.9 C (39.0 F)
1942	-1.1 C (30.0 F)
1943	0.6 C (33.1 F)
1944	0.6 C (33.1 F)
1945	0.6 C (33.1 F)
1946	0.6 C (33.1 F)
1947	-0.6 C (30.9 F)
1948	-8.3 C (17.1 F)
1949	0.0 C (32.0 F)
1950	-2.2 C (28.0 F)
1951	-3.3 C (26.1 F)
1952	0.0 C (32.0 F)
1953	-4.4 C (24.1 F)
1954	-5.0 C (23.0 F)
1955	-5.0 C (23.0 F)
1956	-6.1 C (21.0 F)
1957	-5.0 C (23.0 F)
1958	-5.0 C (23.0 F)
1959	0.0 C (32.0 F)
1960	0.0 C (32.0 F)
1961	-5.0 C (23.0 F)
1962	-6.1 C (21.0 F)
1963	-10.0 C (14.0 F)
1964	-10.0 C (14.0 F)
1965	-6.1 C (21.0 F)
1966	-10.0 C (14.0 F)
1967	-10.0 C (14.0 F)
1968	-10.0 C (14.0 F)
1969	-6.1 C (21.0 F)
1970	-8.3 C (17.1 F)
1971	-7.2 C (19.0 F)
1972	-6.1 C (21.0 F)
1973	-8.3 C (17.1 F)
1974	-7.2 C (19.0 F)
1975	-7.2 C (19.0 F)
1976	-10.0 C (14.0 F)
1977	-5.0 C (23.0 F)
1978	-2.2 C (28.0 F)
1979	-5.0 C (23.0 F)
1980	-2.8 C (27.0 F)
1981	-1.1 C (30.0 F)
1982	-2.2 C (28.0 F)
1983	-4.4 C (24.1 F)
1984	-1.7 C (28.9 F)
1985	-6.1 C (21.0 F)
1986	-3.3 C (26.1 F)
1987	-5.0 C (23.0 F)
1988	-6.1 C (21.0 F)
1989	-6.1 C (21.0 F)
1990	-4.4 C (24.1 F)
1991	-1.1 C (30.0 F)
1992	-1.1 C (30.0 F)
1993	-1.7 C (28.9 F)
1994	-3.3 C (26.1 F)
1995	-2.2 C (28.0 F)
1996	-3.9 C (25.0 F)
1997	-8.3 C (17.1 F)
1998	-2.2 C (28.0 F)
1999	-4.4 C (24.1 F)
2000	-4.4 C (24.1 F)
2001	-2.2 C (28.0 F)
2002	-4.4 C (24.1 F)
2003	-6.1 C (21.0 F)
2004	-6.1 C (21.0 F)
2005	-2.2 C (28.0 F)
2006	-3.3 C (26.1 F)
2007	-1.1 C (30.0 F)
2008	-2.2 C (28.0 F)
2009	-2.2 C (28.0 F)
2010	-5.0 C (23.0 F)
2011	-5.0 C (23.0 F)
2012	0.0 C (32.0 F)

Wettest day (Rx1day)

The wettest day of the year at Zacualtipan (Smn), 1941 to 2012. The record is 348.5 mm (13.7 in) in 1954, marked on the chart; the median year is 83.8 mm (3.3 in).

Wettest day (Rx1day) at Zacualtipan (Smn) by year
Year	Wettest day (Rx1day)
1941	37.8 mm (1.5 in)
1942	95.8 mm (3.8 in)
1943	62.0 mm (2.4 in)
1944	83.8 mm (3.3 in)
1945	31.8 mm (1.3 in)
1946	62.0 mm (2.4 in)
1947	62.0 mm (2.4 in)
1948	78.0 mm (3.1 in)
1949	136.9 mm (5.4 in)
1950	81.8 mm (3.2 in)
1951	95.8 mm (3.8 in)
1952	159.8 mm (6.3 in)
1953	84.3 mm (3.3 in)
1954	348.5 mm (13.7 in)
1955	220.0 mm (8.7 in)
1956	113.8 mm (4.5 in)
1957	55.9 mm (2.2 in)
1958	179.8 mm (7.1 in)
1959	94.0 mm (3.7 in)
1960	47.0 mm (1.9 in)
1961	86.9 mm (3.4 in)
1962	85.9 mm (3.4 in)
1963	78.0 mm (3.1 in)
1964	47.0 mm (1.9 in)
1965	64.8 mm (2.6 in)
1966	90.9 mm (3.6 in)
1967	83.8 mm (3.3 in)
1968	47.0 mm (1.9 in)
1969	167.9 mm (6.6 in)
1970	71.1 mm (2.8 in)
1971	71.4 mm (2.8 in)
1972	77.2 mm (3.0 in)
1973	80.8 mm (3.2 in)
1974	279.9 mm (11.0 in)
1975	148.3 mm (5.8 in)
1976	63.8 mm (2.5 in)
1977	54.4 mm (2.1 in)
1978	93.5 mm (3.7 in)
1979	81.3 mm (3.2 in)
1980	63.8 mm (2.5 in)
1981	140.0 mm (5.5 in)
1982	84.1 mm (3.3 in)
1983	54.4 mm (2.1 in)
1984	133.6 mm (5.3 in)
1985	63.5 mm (2.5 in)
1986	42.4 mm (1.7 in)
1987	37.3 mm (1.5 in)
1988	179.8 mm (7.1 in)
1989	45.5 mm (1.8 in)
1990	50.3 mm (2.0 in)
1991	79.8 mm (3.1 in)
1992	83.8 mm (3.3 in)
1993	149.6 mm (5.9 in)
1994	45.0 mm (1.8 in)
1995	132.1 mm (5.2 in)
1996	52.6 mm (2.1 in)
1997	55.9 mm (2.2 in)
1998	65.8 mm (2.6 in)
1999	176.8 mm (7.0 in)
2000	73.4 mm (2.9 in)
2001	119.9 mm (4.7 in)
2002	103.9 mm (4.1 in)
2003	111.3 mm (4.4 in)
2004	48.8 mm (1.9 in)
2005	154.9 mm (6.1 in)
2006	142.0 mm (5.6 in)
2007	199.9 mm (7.9 in)
2008	119.9 mm (4.7 in)
2009	162.8 mm (6.4 in)
2010	172.0 mm (6.8 in)
2011	112.8 mm (4.4 in)
2012	74.9 mm (2.9 in)

Wettest five days (Rx5day)

The wettest five days of the year at Zacualtipan (Smn), 1941 to 2012. The record is 835.2 mm (32.9 in) in 1954, marked on the chart; the median year is 190.8 mm (7.5 in).

Wettest five days (Rx5day) at Zacualtipan (Smn) by year
Year	Wettest five days (Rx5day)
1941	70.6 mm (2.8 in)
1942	310.5 mm (12.2 in)
1943	96.6 mm (3.8 in)
1944	184.2 mm (7.3 in)
1945	62.3 mm (2.5 in)
1946	126.0 mm (5.0 in)
1947	173.3 mm (6.8 in)
1948	181.4 mm (7.1 in)
1949	282.5 mm (11.1 in)
1950	175.5 mm (6.9 in)
1951	222.5 mm (8.8 in)
1952	555.5 mm (21.9 in)
1953	278.3 mm (11.0 in)
1954	835.2 mm (32.9 in)
1955	712.0 mm (28.0 in)
1956	360.2 mm (14.2 in)
1957	138.6 mm (5.5 in)
1958	486.4 mm (19.1 in)
1959	217.5 mm (8.6 in)
1960	131.1 mm (5.2 in)
1961	286.5 mm (11.3 in)
1962	169.2 mm (6.7 in)
1963	158.3 mm (6.2 in)
1964	87.6 mm (3.4 in)
1965	144.3 mm (5.7 in)
1966	217.5 mm (8.6 in)
1967	294.1 mm (11.6 in)
1968	113.1 mm (4.5 in)
1969	372.3 mm (14.7 in)
1970	149.1 mm (5.9 in)
1971	197.5 mm (7.8 in)
1972	204.8 mm (8.1 in)
1973	163.8 mm (6.4 in)
1974	601.3 mm (23.7 in)
1975	415.8 mm (16.4 in)
1976	180.1 mm (7.1 in)
1977	113.1 mm (4.5 in)
1978	213.1 mm (8.4 in)
1979	122.1 mm (4.8 in)
1980	186.8 mm (7.4 in)
1981	264.0 mm (10.4 in)
1982	189.0 mm (7.4 in)
1983	145.3 mm (5.7 in)
1984	426.5 mm (16.8 in)
1985	126.3 mm (5.0 in)
1986	92.9 mm (3.7 in)
1987	84.5 mm (3.3 in)
1988	375.0 mm (14.8 in)
1989	106.2 mm (4.2 in)
1990	83.5 mm (3.3 in)
1991	195.9 mm (7.7 in)
1992	147.7 mm (5.8 in)
1993	247.2 mm (9.7 in)
1994	71.7 mm (2.8 in)
1995	140.4 mm (5.5 in)
1996	153.5 mm (6.0 in)
1997	95.7 mm (3.8 in)
1998	208.3 mm (8.2 in)
1999	400.2 mm (15.8 in)
2000	192.5 mm (7.6 in)
2001	235.3 mm (9.3 in)
2002	224.6 mm (8.8 in)
2003	245.0 mm (9.6 in)
2004	151.5 mm (6.0 in)
2005	414.3 mm (16.3 in)
2006	150.9 mm (5.9 in)
2007	228.9 mm (9.0 in)
2008	264.9 mm (10.4 in)
2009	288.5 mm (11.4 in)
2010	235.3 mm (9.3 in)
2011	368.3 mm (14.5 in)
2012	116.8 mm (4.6 in)

Longest dry spell (CDD)

The longest dry spell of the year at Zacualtipan (Smn), 1941 to 2012. The record is 75 days in 1948, marked on the chart; the median year is 26 days.

Longest dry spell (CDD) at Zacualtipan (Smn) by year
Year	Longest dry spell (CDD)
1941	10 days
1942	21 days
1943	24 days
1944	34 days
1945	23 days
1946	22 days
1947	64 days
1948	75 days
1949	38 days
1950	22 days
1951	38 days
1952	23 days
1953	46 days
1954	19 days
1955	46 days
1956	30 days
1957	47 days
1958	44 days
1959	26 days
1960	31 days
1961	25 days
1962	34 days
1963	20 days
1964	15 days
1965	29 days
1966	17 days
1967	23 days
1968	23 days
1969	38 days
1970	29 days
1971	22 days
1972	19 days
1973	24 days
1974	15 days
1975	25 days
1976	20 days
1977	31 days
1978	34 days
1979	32 days
1980	23 days
1981	24 days
1982	30 days
1983	38 days
1984	30 days
1985	22 days
1986	26 days
1987	38 days
1988	39 days
1989	26 days
1990	30 days
1991	17 days
1992	26 days
1993	36 days
1994	14 days
1995	20 days
1996	24 days
1997	16 days
1998	38 days
1999	27 days
2000	26 days
2001	32 days
2002	33 days
2003	31 days
2004	17 days
2005	30 days
2006	32 days
2007	19 days
2008	23 days
2009	39 days
2010	28 days
2011	29 days
2012	10 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

50 years with a frost

Across 50 years with a frost, the median last spring frost at Zacualtipan (Smn) falls on 10 March and the median first autumn frost on 5 November, which leaves a median of 239 days between them.

Fitted over all years, the growing season changes by +5.3 days per decade at this station.

Frost dates and growing season at Zacualtipan (Smn)
Measure	Median, all years	Earliest period	Recent period (1973 to 2010)	Recent against earliest	Fitted trend
Last spring frost	10 March	n/a	10 March	n/a	-3.0 days per decade
First autumn frost	5 November	n/a	8 November	n/a	+2.3 days per decade
Growing days	239 days	n/a	247 days	n/a	+5.3 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

69 years, 1943 to 2011

A day with at least 86.7 mm (3.4 in) of rain is expected about once in 2 years. A day with at least 333.6 mm (13.1 in) of rain is expected about once in 100 years.

Rainfall return levels at Zacualtipan (Smn): the daily rain expected about once in a given number of years
Expected about once in	A day with at least	Note
2 years	86.7 mm (3.4 in)
5 years	133.9 mm (5.3 in)
10 years	171.6 mm (6.8 in)
25 years	228.0 mm (9.0 in)
50 years	277.3 mm (10.9 in)
100 years	333.6 mm (13.1 in)	Longer than the 69 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, 69 years of values from 1943 to 2011.

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: 348.5 mm (13.7 in) in 1954; 279.9 mm (11.0 in) in 1974; 220.0 mm (8.7 in) in 1955.

Station Changes

2 suspected

2 changes were suspected in the annual mean temperature of Zacualtipan (Smn), at 1977 and 1995. Each is measured against neighbouring stations.

Relative to 5 neighbouring stations, the station's annual mean temperature from 1977 ran 1.7 C (3.0 F) higher than in the years before (likely change).
Relative to 5 neighbouring stations, the station's annual mean temperature from 1995 ran 0.9 C (1.5 F) higher than in the years before (possible change).

Suspected changes in the annual mean temperature at Zacualtipan (Smn), against neighbouring stations
Year	Shift (C)	Shift (F)	Strength	Neighbours
1977	+1.7	+3.0	likely	5
1995	+0.9	+1.5	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 Zacualtipan (Smn) standing records by year: CSV or JSON. Field meanings are on the data page.
Data for Zacualtipan (Smn) 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).