Ciudad Serdan (Smn) Weather Records (MXN00021026)

Record envelope, standing records and threshold days for Ciudad Serdan (Smn) (MXN00021026), Mexico, with 69 years of record.

Key Facts for Ciudad Serdan (Smn)

Ciudad Serdan (Smn) (MXN00021026) is a weather station in Mexico at 18.98 latitude and -97.43 longitude, 2,561 m (8,402 ft) above sea level.
The station reports from 1941 to 2009, 69 years of record.
1,464 records set at Ciudad Serdan (Smn) still stand.
Records are tracked for tmax, tmin, prcp: an element needs 30 years of data to be eligible.
Ciudad Serdan (Smn) tied a daily record high minimum temperature of 6.7 C (44.1 F) on 27 December 2009.

About the Station

Location: Mexico, 18.98 latitude, -97.43 longitude.
Elevation: 2,561 m (8,402 ft).
Period of record: 1941 to 2009, 69 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 Ciudad Serdan (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 Ciudad Serdan (Smn), with 2026 drawn through them
Month	Highest record high	Lowest record low	2026 highest maximum	2026 lowest minimum
Jan	33.9 C (93.0 F)	-9.4 C (15.1 F)	n/a	n/a
Feb	33.9 C (93.0 F)	-9.4 C (15.1 F)	n/a	n/a
Mar	35.6 C (96.1 F)	-3.3 C (26.1 F)	n/a	n/a
Apr	35.6 C (96.1 F)	-1.1 C (30.0 F)	n/a	n/a
May	36.7 C (98.1 F)	-4.4 C (24.1 F)	n/a	n/a
Jun	32.8 C (91.0 F)	1.7 C (35.1 F)	n/a	n/a
Jul	35.6 C (96.1 F)	1.7 C (35.1 F)	n/a	n/a
Aug	32.8 C (91.0 F)	0.6 C (33.1 F)	n/a	n/a
Sep	31.7 C (89.1 F)	-2.2 C (28.0 F)	n/a	n/a
Oct	32.8 C (91.0 F)	-8.3 C (17.1 F)	n/a	n/a
Nov	32.8 C (91.0 F)	-8.3 C (17.1 F)	n/a	n/a
Dec	30.6 C (87.1 F)	-8.3 C (17.1 F)	n/a	n/a

Which Years Hold Standing Records

1,464 standing records

1,464 records at Ciudad Serdan (Smn) still stand. 1998 holds the most, with 119.

Standing records at Ciudad Serdan (Smn) by the year they were set
Year set	Standing records
1941	31
1942	10
1945	14
1946	19
1947	36
1948	17
1949	17
1950	24
1951	30
1952	43
1953	16
1954	8
1956	25
1957	25
1958	16
1959	9
1960	11
1961	56
1962	6
1963	10
1964	15
1965	20
1966	18
1967	12
1968	17
1969	13
1970	19
1971	16
1972	10
1973	19
1974	36
1975	17
1976	28
1977	7
1978	44
1979	29
1980	37
1981	18
1982	20
1983	31
1984	22
1985	28
1986	29
1987	27
1988	12
1989	9
1992	11
1998	119
1999	115
2000	88
2001	59
2002	47
2007	20
2008	8
2009	21

All-Time Record Progression

4 new records

4 all-time records were set at Ciudad Serdan (Smn) between 8 March 1992 and 2 January 2008. Each dot is a new record.

When Ciudad Serdan (Smn) set new all-time records
Date	Kind	Detail
1992-03-08	Record high minimum temperature	Record high minimum temperature 16.1 C (61.0 F)
1999-04-05	Record high maximum temperature	Record high maximum temperature 35.6 C (96.1 F)
2001-05-20	Record high maximum temperature	Record high maximum temperature 36.7 C (98.1 F)
2008-01-02	Record low maximum temperature	Record low maximum temperature 7.8 C (46.0 F)

Wettest Day of Each Month

Jun: 220.0 mm (8.7 in)

The wettest day on record for each calendar month at Ciudad Serdan (Smn). The most was 220.0 mm (8.7 in) on 7 June 1941.

Record daily precipitation for each month at Ciudad Serdan (Smn)
Month	Record daily precipitation (mm)	Date
Jan	24.9 mm (1.0 in)	11 January 1984
Feb	20.8 mm (0.8 in)	26 February 1982
Mar	125.0 mm (4.9 in)	21 March 1941
Apr	179.8 mm (7.1 in)	22 April 1941
May	111.8 mm (4.4 in)	25 May 1941
Jun	220.0 mm (8.7 in)	7 June 1941
Jul	119.9 mm (4.7 in)	2 July 1941
Aug	55.9 mm (2.2 in)	3 August 1965
Sep	89.9 mm (3.5 in)	6 September 1969
Oct	66.8 mm (2.6 in)	5 October 1999
Nov	19.3 mm (0.8 in)	15 November 1947
Dec	17.8 mm (0.7 in)	12 December 1955

Period of Record Coverage

1941 to 2009

56 years of record at Ciudad Serdan (Smn), 1941 to 2009. 9 years have data for under 90 percent of days and are left out of rankings: 1941, 1942, 1945, 1954, 1967, 1990, 1992, 1998 and others.

Days with data per year at Ciudad Serdan (Smn)
Year	Days with data	Share of year	Complete
1941	173	47%	No
1942	62	17%	No
1945	214	59%	No
1946	365	100%	Yes
1947	365	100%	Yes
1948	366	100%	Yes
1949	365	100%	Yes
1950	365	100%	Yes
1951	365	100%	Yes
1952	366	100%	Yes
1953	365	100%	Yes
1954	306	84%	No
1956	363	99%	Yes
1957	365	100%	Yes
1958	365	100%	Yes
1959	365	100%	Yes
1960	366	100%	Yes
1961	355	97%	Yes
1962	358	98%	Yes
1963	357	98%	Yes
1964	330	90%	Yes
1965	358	98%	Yes
1966	356	98%	Yes
1967	298	82%	No
1968	360	98%	Yes
1969	363	99%	Yes
1970	364	100%	Yes
1971	365	100%	Yes
1972	335	92%	Yes
1973	333	91%	Yes
1974	365	100%	Yes
1975	365	100%	Yes
1976	366	100%	Yes
1977	364	100%	Yes
1978	365	100%	Yes
1979	365	100%	Yes
1980	366	100%	Yes
1981	365	100%	Yes
1982	365	100%	Yes
1983	365	100%	Yes
1984	330	90%	Yes
1985	358	98%	Yes
1986	358	98%	Yes
1987	362	99%	Yes
1988	335	92%	Yes
1989	335	92%	Yes
1990	31	8%	No
1992	31	8%	No
1998	166	45%	No
1999	302	83%	No
2000	366	100%	Yes
2001	365	100%	Yes
2002	365	100%	Yes
2007	363	99%	Yes
2008	366	100%	Yes
2009	361	99%	Yes

Latest Records

Latest records at Ciudad Serdan (Smn)
Date	Station	Record	Value	Beat old record by	Old record stood	Significance
27 December 2009	Ciudad Serdan (Smn), MX	daily high min (Tie)	6.7 C (44.1 F)	tie	39 years	4 of 100 (Routine)
20 December 2009	Ciudad Serdan (Smn), MX	daily high min (Tie)	6.7 C (44.1 F)	tie	22 years	3 of 100 (Routine)
19 December 2009	Ciudad Serdan (Smn), MX	daily high min (Tie)	5.6 C (42.1 F)	tie	40 years	4 of 100 (Routine)
17 December 2009	Ciudad Serdan (Smn), MX	daily high min	7.8 C (46.0 F)	2.2 C (4.0 F)	64 years	32 of 100 (Routine)
17 December 2009	Ciudad Serdan (Smn), MX	daily rain	4.8 mm (0.19 in)	4.0 mm (0.16 in)	42 years	20 of 100 (Routine)
16 December 2009	Ciudad Serdan (Smn), MX	daily high max (Tie)	28.9 C (84.0 F)	tie	8 years	2 of 100 (Routine)
13 December 2009	Ciudad Serdan (Smn), MX	daily high min (Tie)	6.7 C (44.1 F)	tie	62 years	6 of 100 (Routine)
11 December 2009	Ciudad Serdan (Smn), MX	daily high min (Tie)	5.6 C (42.1 F)	tie	32 years	3 of 100 (Routine)
10 December 2009	Ciudad Serdan (Smn), MX	monthly high min (Tie)	8.9 C (48.0 F)	tie	31 years	6 of 100 (Routine)
9 December 2009	Ciudad Serdan (Smn), MX	daily high max (Tie)	27.8 C (82.0 F)	tie	8 years	2 of 100 (Routine)
8 December 2009	Ciudad Serdan (Smn), MX	daily high min (Tie)	5.6 C (42.1 F)	tie	36 years	4 of 100 (Routine)
3 December 2009	Ciudad Serdan (Smn), MX	daily high min (Tie)	7.8 C (46.0 F)	tie	31 years	3 of 100 (Routine)
3 December 2009	Ciudad Serdan (Smn), MX	daily high max (Tie)	30.0 C (86.0 F)	tie	7 years	2 of 100 (Routine)
2 December 2009	Ciudad Serdan (Smn), MX	daily high min (Tie)	6.7 C (44.1 F)	tie	39 years	4 of 100 (Routine)
1 December 2009	Ciudad Serdan (Smn), MX	monthly high min (Tie)	8.9 C (48.0 F)	tie	30 years	6 of 100 (Routine)
25 November 2009	Ciudad Serdan (Smn), MX	daily low max (Tie)	15.6 C (60.1 F)	tie	35 years	4 of 100 (Routine)
8 November 2009	Ciudad Serdan (Smn), MX	daily high min (Tie)	8.9 C (48.0 F)	tie	38 years	4 of 100 (Routine)
1 November 2009	Ciudad Serdan (Smn), MX	daily high min (Tie)	8.9 C (48.0 F)	tie	40 years	4 of 100 (Routine)
30 October 2009	Ciudad Serdan (Smn), MX	daily high min	10.0 C (50.0 F)	1.1 C (2.0 F)	38 years	21 of 100 (Routine)
29 October 2009	Ciudad Serdan (Smn), MX	daily high min (Tie)	10.0 C (50.0 F)	tie	11 years	2 of 100 (Routine)

Climate Trend

41 complete years, 1946 to 2009

One stripe for each of 41 complete years at Ciudad Serdan (Smn), 1946 to 2009. Blue stripes are years cooler than the station's own mean of 13.6 C (56.4 F); red stripes are warmer. The coolest year was 1950, at 12.1 C (53.7 F), and the warmest was 2001, at 16.6 C (61.8 F). The strongest colour marks a difference of 3.1 C (5.6 F).

Annual mean temperature at Ciudad Serdan (Smn) as warming stripes, 1946 to 2009
Year	Annual mean temperature	Difference from the station mean
1946	13.5 C	-0.03 C
1947	13.2 C	-0.38 C
1948	12.7 C	-0.82 C
1949	12.5 C	-1.02 C
1950	12.1 C	-1.48 C
1951	13.0 C	-0.56 C
1952	12.7 C	-0.87 C
1953	13.9 C	+0.33 C
1956	13.1 C	-0.46 C
1957	13.6 C	+0.01 C
1958	13.0 C	-0.57 C
1959	13.2 C	-0.35 C
1960	13.2 C	-0.37 C
1961	13.6 C	+0.07 C
1962	12.7 C	-0.88 C
1963	12.9 C	-0.65 C
1965	12.9 C	-0.70 C
1966	12.6 C	-0.97 C
1968	13.1 C	-0.47 C
1969	14.3 C	+0.69 C
1970	13.7 C	+0.15 C
1971	14.3 C	+0.77 C
1974	13.6 C	+0.03 C
1975	12.8 C	-0.73 C
1976	12.7 C	-0.82 C
1977	13.6 C	+0.08 C
1978	13.6 C	+0.04 C
1979	13.0 C	-0.53 C
1980	14.2 C	+0.59 C
1981	12.9 C	-0.66 C
1982	12.8 C	-0.76 C
1983	14.2 C	+0.60 C
1985	12.9 C	-0.63 C
1986	13.0 C	-0.55 C
1987	13.1 C	-0.43 C
2000	16.5 C	+2.94 C
2001	16.6 C	+3.02 C
2002	16.2 C	+2.61 C
2007	14.7 C	+1.13 C
2008	14.5 C	+0.92 C
2009	15.5 C	+1.91 C

The annual mean temperature here has risen by 0.4 C (0.3 to 0.5) per decade over 1946 to 2009. In Fahrenheit: 0.7 F (0.5 to 1.0) per decade. The slope is a straight line fitted to 41 complete years; the brackets give its 95 percent interval.

Fitted temperature trends per decade at Ciudad Serdan (Smn)
Measure	Per decade (C)	Per decade (F)	Period	Complete years	Reading
Annual mean temperature	0.4 C (0.3 to 0.5) per decade	0.7 F (0.5 to 1.0) per decade	1946 to 2009	41	Rise
Mean daily maximum	0.31 C (0.02 to 0.60) per decade	0.56 F (0.04 to 1.09) per decade	1946 to 2009	41	Rise
Mean daily minimum	0.5 C (0.3 to 0.6) per decade	0.9 F (0.6 to 1.1) per decade	1946 to 2009	41	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 2009

Yearly extremes at Ciudad Serdan (Smn): the record and the median year
Measure	Record	Year of the record	Median year	Years with a value
Hottest day (TXx)	36.7 C (98.1 F)	2001	30.0 C (86.0 F)	56
Coldest night (TNn)	-9.4 C (15.1 F)	1956	-2.7 C (27.1 F)	56
Wettest day (Rx1day)	220.0 mm (8.7 in)	1941	41.9 mm (1.6 in)	57
Wettest five days (Rx5day)	437.9 mm (17.2 in)	1941	80.6 mm (3.2 in)	57
Longest dry spell (CDD)	96 days	1949	61 days	57

Hottest day (TXx)

The hottest day of the year at Ciudad Serdan (Smn), 1941 to 2009. The record is 36.7 C (98.1 F) in 2001, marked on the chart; the median year is 30.0 C (86.0 F).

Hottest day (TXx) at Ciudad Serdan (Smn) by year
Year	Hottest day (TXx)
1941	33.9 C (93.0 F)
1942	28.9 C (84.0 F)
1945	27.8 C (82.0 F)
1946	27.8 C (82.0 F)
1947	26.7 C (80.1 F)
1948	30.0 C (86.0 F)
1949	27.8 C (82.0 F)
1950	27.8 C (82.0 F)
1951	27.8 C (82.0 F)
1952	30.0 C (86.0 F)
1953	33.9 C (93.0 F)
1954	32.8 C (91.0 F)
1955	n/a
1956	33.9 C (93.0 F)
1957	32.8 C (91.0 F)
1958	31.7 C (89.1 F)
1959	31.7 C (89.1 F)
1960	30.6 C (87.1 F)
1961	33.9 C (93.0 F)
1962	28.9 C (84.0 F)
1963	30.0 C (86.0 F)
1964	33.9 C (93.0 F)
1965	30.0 C (86.0 F)
1966	30.6 C (87.1 F)
1967	30.0 C (86.0 F)
1968	30.0 C (86.0 F)
1969	30.6 C (87.1 F)
1970	31.7 C (89.1 F)
1971	31.7 C (89.1 F)
1972	31.7 C (89.1 F)
1973	33.9 C (93.0 F)
1974	35.0 C (95.0 F)
1975	30.0 C (86.0 F)
1976	28.9 C (84.0 F)
1977	28.9 C (84.0 F)
1978	30.0 C (86.0 F)
1979	28.9 C (84.0 F)
1980	31.7 C (89.1 F)
1981	28.9 C (84.0 F)
1982	30.0 C (86.0 F)
1983	31.7 C (89.1 F)
1984	31.7 C (89.1 F)
1985	26.7 C (80.1 F)
1986	26.7 C (80.1 F)
1987	28.9 C (84.0 F)
1988	30.0 C (86.0 F)
1989	28.9 C (84.0 F)
1990	20.6 C (69.1 F)
1992	23.9 C (75.0 F)
1998	32.8 C (91.0 F)
1999	35.6 C (96.1 F)
2000	35.0 C (95.0 F)
2001	36.7 C (98.1 F)
2002	35.6 C (96.1 F)
2007	30.0 C (86.0 F)
2008	30.6 C (87.1 F)
2009	35.6 C (96.1 F)

Coldest night (TNn)

The coldest night of the year at Ciudad Serdan (Smn), 1941 to 2009. The record is -9.4 C (15.1 F) in 1956, marked on the chart; the median year is -2.7 C (27.1 F).

Coldest night (TNn) at Ciudad Serdan (Smn) by year
Year	Coldest night (TNn)
1941	2.2 C (36.0 F)
1942	3.9 C (39.0 F)
1945	-4.4 C (24.1 F)
1946	-3.3 C (26.1 F)
1947	-1.1 C (30.0 F)
1948	-2.2 C (28.0 F)
1949	-5.0 C (23.0 F)
1950	-5.0 C (23.0 F)
1951	-2.2 C (28.0 F)
1952	-4.4 C (24.1 F)
1953	-4.4 C (24.1 F)
1954	-2.2 C (28.0 F)
1955	n/a
1956	-9.4 C (15.1 F)
1957	-8.3 C (17.1 F)
1958	-5.0 C (23.0 F)
1959	-1.1 C (30.0 F)
1960	-6.1 C (21.0 F)
1961	-6.1 C (21.0 F)
1962	-4.4 C (24.1 F)
1963	-5.0 C (23.0 F)
1964	-4.4 C (24.1 F)
1965	0.0 C (32.0 F)
1966	0.0 C (32.0 F)
1967	0.0 C (32.0 F)
1968	0.0 C (32.0 F)
1969	0.0 C (32.0 F)
1970	-4.4 C (24.1 F)
1971	-2.2 C (28.0 F)
1972	0.0 C (32.0 F)
1973	0.0 C (32.0 F)
1974	-4.4 C (24.1 F)
1975	-5.0 C (23.0 F)
1976	-5.0 C (23.0 F)
1977	0.0 C (32.0 F)
1978	-2.2 C (28.0 F)
1979	0.0 C (32.0 F)
1980	0.0 C (32.0 F)
1981	-5.0 C (23.0 F)
1982	-4.4 C (24.1 F)
1983	-4.4 C (24.1 F)
1984	0.0 C (32.0 F)
1985	-2.2 C (28.0 F)
1986	0.0 C (32.0 F)
1987	0.0 C (32.0 F)
1988	0.0 C (32.0 F)
1989	-3.3 C (26.1 F)
1990	0.0 C (32.0 F)
1992	5.6 C (42.1 F)
1998	-7.2 C (19.0 F)
1999	-9.4 C (15.1 F)
2000	-4.4 C (24.1 F)
2001	-2.2 C (28.0 F)
2002	-5.0 C (23.0 F)
2007	-2.2 C (28.0 F)
2008	-5.0 C (23.0 F)
2009	-4.4 C (24.1 F)

Wettest day (Rx1day)

The wettest day of the year at Ciudad Serdan (Smn), 1941 to 2009. The record is 220.0 mm (8.7 in) in 1941, marked on the chart; the median year is 41.9 mm (1.6 in).

Wettest day (Rx1day) at Ciudad Serdan (Smn) by year
Year	Wettest day (Rx1day)
1941	220.0 mm (8.7 in)
1942	84.8 mm (3.3 in)
1945	37.3 mm (1.5 in)
1946	33.8 mm (1.3 in)
1947	42.9 mm (1.7 in)
1948	23.9 mm (0.9 in)
1949	47.0 mm (1.9 in)
1950	46.0 mm (1.8 in)
1951	46.0 mm (1.8 in)
1952	55.9 mm (2.2 in)
1953	43.9 mm (1.7 in)
1954	62.0 mm (2.4 in)
1955	74.9 mm (2.9 in)
1956	39.9 mm (1.6 in)
1957	36.8 mm (1.4 in)
1958	31.8 mm (1.3 in)
1959	47.8 mm (1.9 in)
1960	26.9 mm (1.1 in)
1961	42.9 mm (1.7 in)
1962	35.8 mm (1.4 in)
1963	54.9 mm (2.2 in)
1964	24.9 mm (1.0 in)
1965	55.9 mm (2.2 in)
1966	46.0 mm (1.8 in)
1967	41.9 mm (1.6 in)
1968	47.8 mm (1.9 in)
1969	89.9 mm (3.5 in)
1970	38.9 mm (1.5 in)
1971	35.8 mm (1.4 in)
1972	63.8 mm (2.5 in)
1973	17.8 mm (0.7 in)
1974	35.8 mm (1.4 in)
1975	31.8 mm (1.3 in)
1976	51.8 mm (2.0 in)
1977	23.9 mm (0.9 in)
1978	17.8 mm (0.7 in)
1979	23.9 mm (0.9 in)
1980	35.8 mm (1.4 in)
1981	46.0 mm (1.8 in)
1982	41.9 mm (1.6 in)
1983	63.8 mm (2.5 in)
1984	39.9 mm (1.6 in)
1985	39.9 mm (1.6 in)
1986	37.8 mm (1.5 in)
1987	24.9 mm (1.0 in)
1988	59.9 mm (2.4 in)
1989	42.9 mm (1.7 in)
1990	2.8 mm (0.11 in)
1992	29.0 mm (1.1 in)
1998	34.8 mm (1.4 in)
1999	66.8 mm (2.6 in)
2000	54.9 mm (2.2 in)
2001	36.8 mm (1.4 in)
2002	27.9 mm (1.1 in)
2007	54.9 mm (2.2 in)
2008	29.0 mm (1.1 in)
2009	42.9 mm (1.7 in)

Wettest five days (Rx5day)

The wettest five days of the year at Ciudad Serdan (Smn), 1941 to 2009. The record is 437.9 mm (17.2 in) in 1941, marked on the chart; the median year is 80.6 mm (3.2 in).

Wettest five days (Rx5day) at Ciudad Serdan (Smn) by year
Year	Wettest five days (Rx5day)
1941	437.9 mm (17.2 in)
1942	130.5 mm (5.1 in)
1945	67.1 mm (2.6 in)
1946	63.8 mm (2.5 in)
1947	68.8 mm (2.7 in)
1948	67.3 mm (2.6 in)
1949	111.5 mm (4.4 in)
1950	56.9 mm (2.2 in)
1951	79.2 mm (3.1 in)
1952	126.3 mm (5.0 in)
1953	76.5 mm (3.0 in)
1954	68.9 mm (2.7 in)
1955	113.2 mm (4.5 in)
1956	81.3 mm (3.2 in)
1957	72.1 mm (2.8 in)
1958	60.2 mm (2.4 in)
1959	84.1 mm (3.3 in)
1960	79.3 mm (3.1 in)
1961	80.3 mm (3.2 in)
1962	58.4 mm (2.3 in)
1963	93.5 mm (3.7 in)
1964	55.4 mm (2.2 in)
1965	111.4 mm (4.4 in)
1966	125.5 mm (4.9 in)
1967	142.4 mm (5.6 in)
1968	116.1 mm (4.6 in)
1969	143.1 mm (5.6 in)
1970	126.3 mm (5.0 in)
1971	64.8 mm (2.6 in)
1972	96.3 mm (3.8 in)
1973	59.5 mm (2.3 in)
1974	120.2 mm (4.7 in)
1975	93.3 mm (3.7 in)
1976	82.0 mm (3.2 in)
1977	46.6 mm (1.8 in)
1978	61.2 mm (2.4 in)
1979	76.5 mm (3.0 in)
1980	118.4 mm (4.7 in)
1981	157.6 mm (6.2 in)
1982	139.3 mm (5.5 in)
1983	128.3 mm (5.1 in)
1984	97.2 mm (3.8 in)
1985	80.6 mm (3.2 in)
1986	81.3 mm (3.2 in)
1987	56.2 mm (2.2 in)
1988	119.6 mm (4.7 in)
1989	75.4 mm (3.0 in)
1990	2.8 mm (0.11 in)
1992	51.4 mm (2.0 in)
1998	80.5 mm (3.2 in)
1999	109.7 mm (4.3 in)
2000	79.1 mm (3.1 in)
2001	63.0 mm (2.5 in)
2002	66.8 mm (2.6 in)
2007	82.8 mm (3.3 in)
2008	65.0 mm (2.6 in)
2009	100.6 mm (4.0 in)

Longest dry spell (CDD)

The longest dry spell of the year at Ciudad Serdan (Smn), 1941 to 2009. The record is 96 days in 1949, marked on the chart; the median year is 61 days.

Longest dry spell (CDD) at Ciudad Serdan (Smn) by year
Year	Longest dry spell (CDD)
1941	47 days
1942	25 days
1945	35 days
1946	40 days
1947	31 days
1948	56 days
1949	96 days
1950	77 days
1951	62 days
1952	60 days
1953	69 days
1954	64 days
1955	80 days
1956	77 days
1957	48 days
1958	61 days
1959	57 days
1960	65 days
1961	37 days
1962	65 days
1963	94 days
1964	42 days
1965	33 days
1966	65 days
1967	61 days
1968	28 days
1969	62 days
1970	92 days
1971	83 days
1972	35 days
1973	57 days
1974	68 days
1975	75 days
1976	45 days
1977	65 days
1978	54 days
1979	61 days
1980	34 days
1981	70 days
1982	48 days
1983	72 days
1984	62 days
1985	80 days
1986	46 days
1987	92 days
1988	37 days
1989	89 days
1990	19 days
1992	10 days
1998	31 days
1999	59 days
2000	70 days
2001	73 days
2002	39 days
2007	37 days
2008	89 days
2009	52 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

40 years with a frost

Across 40 years with a frost, the median last spring frost at Ciudad Serdan (Smn) falls on 25 February and the median first autumn frost on 31 October, which leaves a median of 248 days between them.

Fitted over all years, the growing season changes by +1.3 days per decade at this station.

Frost dates and growing season at Ciudad Serdan (Smn)
Measure	Median, all years	Earliest period	Recent period (1958 to 2008)	Recent against earliest	Fitted trend
Last spring frost	25 February	n/a	26 February	n/a	-0.3 days per decade
First autumn frost	31 October	n/a	3 November	n/a	+0.9 days per decade
Growing days	248 days	n/a	263 days	n/a	+1.3 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

49 years, 1946 to 2009

A day with at least 40.8 mm (1.6 in) of rain is expected about once in 2 years. A day with at least 83.0 mm (3.3 in) of rain is expected about once in 100 years.

Rainfall return levels at Ciudad Serdan (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	40.8 mm (1.6 in)
5 years	53.8 mm (2.1 in)
10 years	61.6 mm (2.4 in)
25 years	70.8 mm (2.8 in)
50 years	77.1 mm (3.0 in)	Longer than the 49 years of record
100 years	83.0 mm (3.3 in)	Longer than the 49 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, 49 years of values from 1946 to 2009.

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: 89.9 mm (3.5 in) in 1969; 74.9 mm (2.9 in) in 1955; 63.8 mm (2.5 in) in 1972.

Station Changes

No change in the annual mean temperature of this station was found against its neighbours.

Download the Data

Data for Ciudad Serdan (Smn) standing records by year: CSV or JSON. Field meanings are on the data page.
Data for Ciudad Serdan (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 2026-10-15 (15 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).