San Juan del Rio (Smn) Weather Records (MXN00022015)

Record envelope, standing records and threshold days for San Juan del Rio (Smn) (MXN00022015), Mexico, with 59 years of record.

Key Facts for San Juan del Rio (Smn)

San Juan del Rio (Smn) (MXN00022015) is a weather station in Mexico at 20.38 latitude and -100.00 longitude, 1,914 m (6,279 ft) above sea level.
The station reports from 1922 to 1980, 59 years of record.
1,464 records set at San Juan del Rio (Smn) still stand.
Records are tracked for tmax, tmin, prcp: an element needs 30 years of data to be eligible.
San Juan del Rio (Smn) tied a daily record low minimum temperature of 0.0 C (32.0 F) on 29 December 1980.

About the Station

Location: Mexico, 20.38 latitude, -100.00 longitude.
Elevation: 1,914 m (6,279 ft).
Period of record: 1922 to 1980, 59 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 Juan del Rio (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 San Juan del Rio (Smn), with 2026 drawn through them
Month	Highest record high	Lowest record low	2026 highest maximum	2026 lowest minimum
Jan	31.7 C (89.1 F)	-4.4 C (24.1 F)	n/a	n/a
Feb	30.6 C (87.1 F)	-4.4 C (24.1 F)	n/a	n/a
Mar	35.0 C (95.0 F)	-2.2 C (28.0 F)	n/a	n/a
Apr	34.4 C (93.9 F)	0.0 C (32.0 F)	n/a	n/a
May	35.0 C (95.0 F)	3.9 C (39.0 F)	n/a	n/a
Jun	35.0 C (95.0 F)	5.0 C (41.0 F)	n/a	n/a
Jul	31.1 C (88.0 F)	4.4 C (39.9 F)	n/a	n/a
Aug	32.2 C (90.0 F)	3.9 C (39.0 F)	n/a	n/a
Sep	31.1 C (88.0 F)	1.1 C (34.0 F)	n/a	n/a
Oct	30.0 C (86.0 F)	-5.0 C (23.0 F)	n/a	n/a
Nov	30.0 C (86.0 F)	-3.3 C (26.1 F)	n/a	n/a
Dec	28.3 C (82.9 F)	-2.2 C (28.0 F)	n/a	n/a

Which Years Hold Standing Records

1,464 standing records

1,464 records at San Juan del Rio (Smn) still stand. 1936 holds the most, with 177.

Standing records at San Juan del Rio (Smn) by the year they were set
Year set	Standing records
1922	45
1923	36
1924	54
1925	59
1926	82
1927	94
1928	71
1929	38
1930	52
1931	28
1933	9
1936	177
1937	64
1938	72
1939	15
1941	1
1961	27
1962	17
1963	28
1964	16
1965	23
1966	42
1967	28
1968	27
1969	28
1970	25
1971	13
1972	17
1973	34
1974	34
1975	17
1976	37
1977	19
1978	23
1979	35
1980	77

Wettest Day of Each Month

Oct: 156.0 mm (6.1 in)

The wettest day on record for each calendar month at San Juan del Rio (Smn). The most was 156.0 mm (6.1 in) on 11 October 1927.

Record daily precipitation for each month at San Juan del Rio (Smn)
Month	Record daily precipitation (mm)	Date
Jan	24.1 mm (0.9 in)	27 January 1929
Feb	79.8 mm (3.1 in)	7 February 1937
Mar	57.4 mm (2.3 in)	20 March 1922
Apr	54.9 mm (2.2 in)	24 April 1927
May	49.8 mm (2.0 in)	11 May 1936
Jun	108.0 mm (4.3 in)	25 June 1927
Jul	86.4 mm (3.4 in)	23 July 1973
Aug	55.4 mm (2.2 in)	22 August 1927
Sep	149.9 mm (5.9 in)	9 September 1927
Oct	156.0 mm (6.1 in)	11 October 1927
Nov	31.8 mm (1.3 in)	17 November 1927
Dec	28.4 mm (1.1 in)	1 December 1967

Period of Record Coverage

1922 to 1980

36 years of record at San Juan del Rio (Smn), 1922 to 1980. 5 years have data for under 90 percent of days and are left out of rankings: 1931, 1933, 1936, 1939, 1941.

Days with data per year at San Juan del Rio (Smn)
Year	Days with data	Share of year	Complete
1922	362	99%	Yes
1923	365	100%	Yes
1924	351	96%	Yes
1925	364	100%	Yes
1926	365	100%	Yes
1927	365	100%	Yes
1928	338	92%	Yes
1929	365	100%	Yes
1930	364	100%	Yes
1931	313	86%	No
1933	31	8%	No
1936	327	89%	No
1937	334	92%	Yes
1938	363	99%	Yes
1939	89	24%	No
1941	30	8%	No
1961	365	100%	Yes
1962	365	100%	Yes
1963	365	100%	Yes
1964	365	100%	Yes
1965	362	99%	Yes
1966	363	99%	Yes
1967	365	100%	Yes
1968	363	99%	Yes
1969	362	99%	Yes
1970	365	100%	Yes
1971	365	100%	Yes
1972	335	92%	Yes
1973	365	100%	Yes
1974	365	100%	Yes
1975	334	92%	Yes
1976	365	100%	Yes
1977	365	100%	Yes
1978	363	99%	Yes
1979	365	100%	Yes
1980	366	100%	Yes

Latest Records

Latest records at San Juan del Rio (Smn)
Date	Station	Record	Value	Beat old record by	Old record stood	Significance
29 December 1980	San Juan del Rio (Smn), MX	daily low min (Tie)	0.0 C (32.0 F)	tie	42 years	4 of 100 (Routine)
19 December 1980	San Juan del Rio (Smn), MX	daily low min (Tie)	0.0 C (32.0 F)	tie	43 years	4 of 100 (Routine)
15 December 1980	San Juan del Rio (Smn), MX	daily high max (Tie)	25.0 C (77.0 F)	tie	6 years	1 of 100 (Routine)
9 December 1980	San Juan del Rio (Smn), MX	daily high max (Tie)	25.6 C (78.1 F)	tie	56 years	5 of 100 (Routine)
9 December 1980	San Juan del Rio (Smn), MX	daily high min (Tie)	10.0 C (50.0 F)	tie	53 years	5 of 100 (Routine)
8 December 1980	San Juan del Rio (Smn), MX	daily high max	27.2 C (81.0 F)	2.2 C (4.0 F)	56 years	27 of 100 (Routine)
5 December 1980	San Juan del Rio (Smn), MX	daily high max (Tie)	25.6 C (78.1 F)	tie	44 years	4 of 100 (Routine)
26 November 1980	San Juan del Rio (Smn), MX	daily high max (Tie)	26.1 C (79.0 F)	tie	15 years	2 of 100 (Routine)
25 November 1980	San Juan del Rio (Smn), MX	daily high max	26.1 C (79.0 F)	0.5 C (0.9 F)	54 years	22 of 100 (Routine)
23 November 1980	San Juan del Rio (Smn), MX	daily high min (Tie)	10.0 C (50.0 F)	tie	1 year	1 of 100 (Routine)
3 November 1980	San Juan del Rio (Smn), MX	daily high min (Tie)	12.8 C (55.0 F)	tie	54 years	5 of 100 (Routine)
2 November 1980	San Juan del Rio (Smn), MX	daily rain	17.3 mm (0.7 in)	17.3 mm (0.7 in)	58 years	20 of 100 (Routine)
31 October 1980	San Juan del Rio (Smn), MX	daily low max	16.7 C (62.1 F)	2.2 C (4.0 F)	58 years	29 of 100 (Routine)
29 October 1980	San Juan del Rio (Smn), MX	daily high min	13.3 C (55.9 F)	0.5 C (0.9 F)	1 year	6 of 100 (Routine)
28 October 1980	San Juan del Rio (Smn), MX	daily high min	12.8 C (55.0 F)	0.6 C (1.1 F)	55 years	22 of 100 (Routine)
25 October 1980	San Juan del Rio (Smn), MX	daily high min	12.8 C (55.0 F)	0.6 C (1.1 F)	55 years	22 of 100 (Routine)
22 October 1980	San Juan del Rio (Smn), MX	daily high min (Tie)	13.9 C (57.0 F)	tie	53 years	5 of 100 (Routine)
21 October 1980	San Juan del Rio (Smn), MX	daily high min (Tie)	13.3 C (55.9 F)	tie	50 years	5 of 100 (Routine)
20 October 1980	San Juan del Rio (Smn), MX	daily rain	26.2 mm (1.0 in)	13.8 mm (0.5 in)	50 years	29 of 100 (Routine)
18 October 1980	San Juan del Rio (Smn), MX	monthly high max (Tie)	30.0 C (86.0 F)	tie	41 years	6 of 100 (Routine)

Climate Trend

27 complete years, 1922 to 1980

One stripe for each of 27 complete years at San Juan del Rio (Smn), 1922 to 1980. Blue stripes are years cooler than the station's own mean of 16.5 C (61.7 F); red stripes are warmer. The coolest year was 1923, at 15.0 C (59.0 F), and the warmest was 1980, at 18.3 C (65.0 F). The strongest colour marks a difference of 1.9 C (3.4 F).

Annual mean temperature at San Juan del Rio (Smn) as warming stripes, 1922 to 1980
Year	Annual mean temperature	Difference from the station mean
1922	15.0 C	-1.46 C
1923	15.0 C	-1.48 C
1925	17.3 C	+0.77 C
1926	17.6 C	+1.09 C
1927	17.8 C	+1.31 C
1928	17.8 C	+1.35 C
1929	17.7 C	+1.22 C
1930	17.7 C	+1.21 C
1938	16.0 C	-0.48 C
1961	16.1 C	-0.43 C
1962	16.2 C	-0.27 C
1963	16.1 C	-0.40 C
1964	16.1 C	-0.36 C
1965	16.2 C	-0.33 C
1966	15.4 C	-1.06 C
1967	15.4 C	-1.07 C
1968	15.6 C	-0.94 C
1969	16.7 C	+0.21 C
1970	16.1 C	-0.37 C
1971	16.8 C	+0.27 C
1973	16.5 C	+0.05 C
1974	16.0 C	-0.49 C
1976	15.7 C	-0.76 C
1977	16.4 C	-0.06 C
1978	16.8 C	+0.28 C
1979	16.8 C	+0.33 C
1980	18.3 C	+1.83 C

This station does not have enough complete years (30 are needed) to fit a temperature trend.

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

1922 to 1980

Yearly extremes at San Juan del Rio (Smn): the record and the median year
Measure	Record	Year of the record	Median year	Years with a value
Hottest day (TXx)	35.0 C (95.0 F)	1927	32.0 C (89.5 F)	36
Coldest night (TNn)	-5.0 C (23.0 F)	1922	-2.2 C (28.0 F)	35
Wettest day (Rx1day)	156.0 mm (6.1 in)	1927	46.8 mm (1.8 in)	36
Wettest five days (Rx5day)	417.2 mm (16.4 in)	1927	86.9 mm (3.4 in)	36
Longest dry spell (CDD)	113 days	1924	59 days	36

Hottest day (TXx)

The hottest day of the year at San Juan del Rio (Smn), 1922 to 1980. The record is 35.0 C (95.0 F) in 1927, marked on the chart; the median year is 32.0 C (89.5 F).

Hottest day (TXx) at San Juan del Rio (Smn) by year
Year	Hottest day (TXx)
1922	30.0 C (86.0 F)
1923	28.9 C (84.0 F)
1924	29.4 C (84.9 F)
1925	31.1 C (88.0 F)
1926	30.6 C (87.1 F)
1927	35.0 C (95.0 F)
1928	32.8 C (91.0 F)
1929	32.8 C (91.0 F)
1930	32.8 C (91.0 F)
1931	31.7 C (89.1 F)
1933	28.3 C (82.9 F)
1936	32.8 C (91.0 F)
1937	31.7 C (89.1 F)
1938	30.6 C (87.1 F)
1939	30.0 C (86.0 F)
1941	30.6 C (87.1 F)
1961	32.8 C (91.0 F)
1962	32.8 C (91.0 F)
1963	30.6 C (87.1 F)
1964	32.8 C (91.0 F)
1965	31.7 C (89.1 F)
1966	30.6 C (87.1 F)
1967	32.2 C (90.0 F)
1968	29.4 C (84.9 F)
1969	32.2 C (90.0 F)
1970	32.2 C (90.0 F)
1971	32.2 C (90.0 F)
1972	31.7 C (89.1 F)
1973	33.3 C (91.9 F)
1974	35.0 C (95.0 F)
1975	35.0 C (95.0 F)
1976	31.7 C (89.1 F)
1977	31.7 C (89.1 F)
1978	33.9 C (93.0 F)
1979	32.8 C (91.0 F)
1980	35.0 C (95.0 F)

Coldest night (TNn)

The coldest night of the year at San Juan del Rio (Smn), 1922 to 1980. The record is -5.0 C (23.0 F) in 1922, marked on the chart; the median year is -2.2 C (28.0 F).

Coldest night (TNn) at San Juan del Rio (Smn) by year
Year	Coldest night (TNn)
1922	-5.0 C (23.0 F)
1923	-2.2 C (28.0 F)
1924	-2.2 C (28.0 F)
1925	-2.2 C (28.0 F)
1926	-2.2 C (28.0 F)
1927	-1.1 C (30.0 F)
1928	0.0 C (32.0 F)
1929	1.1 C (34.0 F)
1930	0.0 C (32.0 F)
1931	0.6 C (33.1 F)
1933	n/a
1936	0.0 C (32.0 F)
1937	0.0 C (32.0 F)
1938	0.0 C (32.0 F)
1939	0.0 C (32.0 F)
1941	8.9 C (48.0 F)
1961	-2.2 C (28.0 F)
1962	-3.3 C (26.1 F)
1963	-1.7 C (28.9 F)
1964	-2.2 C (28.0 F)
1965	-3.9 C (25.0 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	-3.3 C (26.1 F)
1971	0.0 C (32.0 F)
1972	0.0 C (32.0 F)
1973	-2.8 C (27.0 F)
1974	-1.7 C (28.9 F)
1975	-2.2 C (28.0 F)
1976	-4.4 C (24.1 F)
1977	-2.2 C (28.0 F)
1978	0.0 C (32.0 F)
1979	-4.4 C (24.1 F)
1980	-1.7 C (28.9 F)

Wettest day (Rx1day)

The wettest day of the year at San Juan del Rio (Smn), 1922 to 1980. The record is 156.0 mm (6.1 in) in 1927, marked on the chart; the median year is 46.8 mm (1.8 in).

Wettest day (Rx1day) at San Juan del Rio (Smn) by year
Year	Wettest day (Rx1day)
1922	57.4 mm (2.3 in)
1923	45.2 mm (1.8 in)
1924	58.7 mm (2.3 in)
1925	65.8 mm (2.6 in)
1926	50.5 mm (2.0 in)
1927	156.0 mm (6.1 in)
1928	41.1 mm (1.6 in)
1929	37.3 mm (1.5 in)
1930	43.7 mm (1.7 in)
1931	50.3 mm (2.0 in)
1933	0.5 mm (0.02 in)
1936	49.8 mm (2.0 in)
1937	79.8 mm (3.1 in)
1938	45.0 mm (1.8 in)
1939	1.8 mm (0.07 in)
1941	22.4 mm (0.9 in)
1961	39.1 mm (1.5 in)
1962	49.3 mm (1.9 in)
1963	56.6 mm (2.2 in)
1964	40.9 mm (1.6 in)
1965	33.0 mm (1.3 in)
1966	37.3 mm (1.5 in)
1967	35.8 mm (1.4 in)
1968	46.0 mm (1.8 in)
1969	73.4 mm (2.9 in)
1970	71.6 mm (2.8 in)
1971	47.8 mm (1.9 in)
1972	41.4 mm (1.6 in)
1973	86.4 mm (3.4 in)
1974	50.0 mm (2.0 in)
1975	50.8 mm (2.0 in)
1976	74.7 mm (2.9 in)
1977	44.2 mm (1.7 in)
1978	47.5 mm (1.9 in)
1979	36.8 mm (1.4 in)
1980	31.0 mm (1.2 in)

Wettest five days (Rx5day)

The wettest five days of the year at San Juan del Rio (Smn), 1922 to 1980. The record is 417.2 mm (16.4 in) in 1927, marked on the chart; the median year is 86.9 mm (3.4 in).

Wettest five days (Rx5day) at San Juan del Rio (Smn) by year
Year	Wettest five days (Rx5day)
1922	87.4 mm (3.4 in)
1923	72.7 mm (2.9 in)
1924	63.8 mm (2.5 in)
1925	93.8 mm (3.7 in)
1926	102.6 mm (4.0 in)
1927	417.2 mm (16.4 in)
1928	90.2 mm (3.6 in)
1929	69.9 mm (2.8 in)
1930	59.5 mm (2.3 in)
1931	83.6 mm (3.3 in)
1933	0.5 mm (0.02 in)
1936	107.0 mm (4.2 in)
1937	114.6 mm (4.5 in)
1938	71.5 mm (2.8 in)
1939	1.8 mm (0.07 in)
1941	29.3 mm (1.2 in)
1961	87.1 mm (3.4 in)
1962	89.5 mm (3.5 in)
1963	76.4 mm (3.0 in)
1964	104.7 mm (4.1 in)
1965	60.7 mm (2.4 in)
1966	86.6 mm (3.4 in)
1967	81.8 mm (3.2 in)
1968	114.4 mm (4.5 in)
1969	108.0 mm (4.3 in)
1970	128.3 mm (5.1 in)
1971	121.6 mm (4.8 in)
1972	58.0 mm (2.3 in)
1973	124.1 mm (4.9 in)
1974	52.6 mm (2.1 in)
1975	105.2 mm (4.1 in)
1976	147.3 mm (5.8 in)
1977	90.7 mm (3.6 in)
1978	58.2 mm (2.3 in)
1979	74.7 mm (2.9 in)
1980	58.7 mm (2.3 in)

Longest dry spell (CDD)

The longest dry spell of the year at San Juan del Rio (Smn), 1922 to 1980. The record is 113 days in 1924, marked on the chart; the median year is 59 days.

Longest dry spell (CDD) at San Juan del Rio (Smn) by year
Year	Longest dry spell (CDD)
1922	53 days
1923	32 days
1924	113 days
1925	24 days
1926	61 days
1927	44 days
1928	50 days
1929	92 days
1930	55 days
1931	69 days
1933	31 days
1936	40 days
1937	64 days
1938	65 days
1939	48 days
1941	5 days
1961	95 days
1962	101 days
1963	86 days
1964	64 days
1965	56 days
1966	56 days
1967	46 days
1968	40 days
1969	86 days
1970	76 days
1971	84 days
1972	52 days
1973	78 days
1974	68 days
1975	102 days
1976	38 days
1977	79 days
1978	40 days
1979	75 days
1980	56 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

33 years, 1922 to 1980

A day with at least 47.1 mm (1.9 in) of rain is expected about once in 2 years. A day with at least 150.6 mm (5.9 in) of rain is expected about once in 100 years.

Rainfall return levels at San Juan del Rio (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	47.1 mm (1.9 in)
5 years	62.5 mm (2.5 in)
10 years	76.4 mm (3.0 in)
25 years	99.7 mm (3.9 in)
50 years	122.3 mm (4.8 in)	Longer than the 33 years of record
100 years	150.6 mm (5.9 in)	Longer than the 33 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, 33 years of values from 1922 to 1980.

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: 156.0 mm (6.1 in) in 1927; 86.4 mm (3.4 in) in 1973; 79.8 mm (3.1 in) in 1937.

Download the Data

Data for San Juan del Rio (Smn) standing records by year: CSV or JSON. Field meanings are on the data page.
Data for San Juan del Rio (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 2026-10-13 (13 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).