St Williams Weather Records (CA006137399)

Record envelope, standing records and threshold days for St Williams (CA006137399), Ontario, Canada, with 35 years of record.

Key Facts for St Williams

St Williams (CA006137399) is a weather station in Ontario, Canada at 42.70 latitude and -80.45 longitude, 213 m (699 ft) above sea level.
The station reports from 1954 to 1988, 35 years of record.
1,464 records set at St Williams still stand.
Records are tracked for tmax, tmin, prcp, snow: an element needs 30 years of data to be eligible.

About the Station

Location: Ontario, Canada, 42.70 latitude, -80.45 longitude.
Elevation: 213 m (699 ft).
Period of record: 1954 to 1988, 35 years.
Eligible elements: tmax, tmin, prcp, snow.

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 St Williams. 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 St Williams, with 2026 drawn through them
Month	Highest record high	Lowest record low	2026 highest maximum	2026 lowest minimum
Jan	13.3 C (55.9 F)	-29.4 C (-20.9 F)	n/a	n/a
Feb	14.4 C (57.9 F)	-28.9 C (-20.0 F)	n/a	n/a
Mar	23.3 C (73.9 F)	-22.2 C (-8.0 F)	n/a	n/a
Apr	28.3 C (82.9 F)	-15.0 C (5.0 F)	n/a	n/a
May	33.3 C (91.9 F)	-7.5 C (18.5 F)	n/a	n/a
Jun	35.0 C (95.0 F)	-1.1 C (30.0 F)	n/a	n/a
Jul	35.0 C (95.0 F)	3.9 C (39.0 F)	n/a	n/a
Aug	34.4 C (93.9 F)	0.0 C (32.0 F)	n/a	n/a
Sep	32.2 C (90.0 F)	-3.3 C (26.1 F)	n/a	n/a
Oct	28.9 C (84.0 F)	-8.9 C (16.0 F)	n/a	n/a
Nov	23.9 C (75.0 F)	-18.9 C (-2.0 F)	n/a	n/a
Dec	19.0 C (66.2 F)	-26.0 C (-14.8 F)	n/a	n/a

Which Years Hold Standing Records

1,464 standing records

1,464 records at St Williams still stand. 1967 holds the most, with 67.

Standing records at St Williams by the year they were set
Year set	Standing records
1954	41
1955	64
1956	50
1957	61
1958	33
1959	65
1960	44
1961	48
1962	55
1963	54
1964	65
1965	65
1966	56
1967	67
1968	38
1969	37
1970	46
1971	43
1972	43
1973	52
1974	45
1975	40
1976	53
1977	65
1978	28
1979	62
1980	33
1981	33
1982	36
1983	42

Wettest Day of Each Month

Sep: 110.4 mm (4.3 in)

The wettest day on record for each calendar month at St Williams. The most was 110.4 mm (4.3 in) on 25 September 1977.

Record daily precipitation for each month at St Williams
Month	Record daily precipitation (mm)	Date
Jan	37.8 mm (1.5 in)	22 January 1957
Feb	41.9 mm (1.6 in)	5 February 1960
Mar	61.0 mm (2.4 in)	1 March 1972
Apr	73.6 mm (2.9 in)	22 April 1977
May	50.3 mm (2.0 in)	24 May 1971
Jun	87.1 mm (3.4 in)	25 June 1968
Jul	88.0 mm (3.5 in)	21 July 1980
Aug	76.7 mm (3.0 in)	1 August 1964
Sep	110.4 mm (4.3 in)	25 September 1977
Oct	74.2 mm (2.9 in)	15 October 1954
Nov	51.6 mm (2.0 in)	3 November 1970
Dec	65.3 mm (2.6 in)	9 December 1966

Period of Record Coverage

1954 to 1983

30 years of record at St Williams, 1954 to 1983. 4 years have data for under 90 percent of days and are left out of rankings: 1954, 1957, 1982, 1983.

Days with data per year at St Williams
Year	Days with data	Share of year	Complete
1954	251	69%	No
1955	336	92%	Yes
1956	365	100%	Yes
1957	324	89%	No
1958	365	100%	Yes
1959	365	100%	Yes
1960	366	100%	Yes
1961	365	100%	Yes
1962	363	99%	Yes
1963	334	92%	Yes
1964	366	100%	Yes
1965	365	100%	Yes
1966	364	100%	Yes
1967	365	100%	Yes
1968	366	100%	Yes
1969	365	100%	Yes
1970	365	100%	Yes
1971	365	100%	Yes
1972	366	100%	Yes
1973	364	100%	Yes
1974	365	100%	Yes
1975	358	98%	Yes
1976	359	98%	Yes
1977	356	98%	Yes
1978	350	96%	Yes
1979	349	96%	Yes
1980	355	97%	Yes
1981	354	97%	Yes
1982	328	90%	No
1983	309	85%	No

Latest Records

No records were set at this station in the latest data.

Climate Trend

22 complete years, 1956 to 1981

One stripe for each of 22 complete years at St Williams, 1956 to 1981. Blue stripes are years cooler than the station's own mean of 7.9 C (46.3 F); red stripes are warmer. The coolest year was 1976, at 7.1 C (44.8 F), and the warmest was 1973, at 8.9 C (48.1 F). The strongest colour marks a difference of 1.0 C (1.8 F).

Annual mean temperature at St Williams as warming stripes, 1956 to 1981
Year	Annual mean temperature	Difference from the station mean
1956	7.8 C	-0.10 C
1958	7.4 C	-0.53 C
1959	8.8 C	+0.84 C
1960	7.9 C	-0.08 C
1961	8.3 C	+0.38 C
1962	7.8 C	-0.12 C
1964	8.2 C	+0.29 C
1965	7.8 C	-0.16 C
1966	7.7 C	-0.29 C
1967	7.7 C	-0.25 C
1968	8.1 C	+0.13 C
1969	8.1 C	+0.14 C
1970	8.1 C	+0.18 C
1971	8.2 C	+0.23 C
1972	7.2 C	-0.79 C
1973	8.9 C	+0.99 C
1974	7.6 C	-0.36 C
1975	8.5 C	+0.59 C
1976	7.1 C	-0.83 C
1977	7.9 C	-0.01 C
1980	7.4 C	-0.50 C
1981	8.2 C	+0.30 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

1954 to 1983

Yearly extremes at St Williams: 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)	1971	32.9 C (91.2 F)	30
Coldest night (TNn)	-29.4 C (-20.9 F)	1976	-25.0 C (-13.0 F)	30
Wettest day (Rx1day)	110.4 mm (4.3 in)	1977	54.0 mm (2.1 in)	30
Wettest five days (Rx5day)	148.4 mm (5.8 in)	1966	90.9 mm (3.6 in)	30
Longest dry spell (CDD)	30 days	1969	17 days	30

Hottest day (TXx)

The hottest day of the year at St Williams, 1954 to 1983. The record is 35.0 C (95.0 F) in 1971, marked on the chart; the median year is 32.9 C (91.2 F).

Hottest day (TXx) at St Williams by year
Year	Hottest day (TXx)
1954	32.2 C (90.0 F)
1955	33.3 C (91.9 F)
1956	33.3 C (91.9 F)
1957	32.2 C (90.0 F)
1958	30.0 C (86.0 F)
1959	33.3 C (91.9 F)
1960	31.1 C (88.0 F)
1961	31.7 C (89.1 F)
1962	33.3 C (91.9 F)
1963	33.3 C (91.9 F)
1964	33.9 C (93.0 F)
1965	32.2 C (90.0 F)
1966	34.4 C (93.9 F)
1967	31.7 C (89.1 F)
1968	32.8 C (91.0 F)
1969	32.8 C (91.0 F)
1970	34.4 C (93.9 F)
1971	35.0 C (95.0 F)
1972	31.7 C (89.1 F)
1973	34.4 C (93.9 F)
1974	31.7 C (89.1 F)
1975	33.9 C (93.0 F)
1976	30.0 C (86.0 F)
1977	33.5 C (92.3 F)
1978	33.0 C (91.4 F)
1979	31.0 C (87.8 F)
1980	30.0 C (86.0 F)
1981	35.0 C (95.0 F)
1982	31.5 C (88.7 F)
1983	35.0 C (95.0 F)

Coldest night (TNn)

The coldest night of the year at St Williams, 1954 to 1983. The record is -29.4 C (-20.9 F) in 1976, marked on the chart; the median year is -25.0 C (-13.0 F).

Coldest night (TNn) at St Williams by year
Year	Coldest night (TNn)
1954	-19.4 C (-2.9 F)
1955	-28.9 C (-20.0 F)
1956	-19.4 C (-2.9 F)
1957	-24.4 C (-11.9 F)
1958	-23.9 C (-11.0 F)
1959	-21.7 C (-7.1 F)
1960	-22.2 C (-8.0 F)
1961	-26.1 C (-15.0 F)
1962	-25.0 C (-13.0 F)
1963	-25.0 C (-13.0 F)
1964	-18.3 C (-0.9 F)
1965	-25.6 C (-14.1 F)
1966	-25.0 C (-13.0 F)
1967	-25.0 C (-13.0 F)
1968	-21.7 C (-7.1 F)
1969	-20.6 C (-5.1 F)
1970	-27.2 C (-17.0 F)
1971	-23.3 C (-9.9 F)
1972	-25.0 C (-13.0 F)
1973	-25.0 C (-13.0 F)
1974	-23.9 C (-11.0 F)
1975	-21.7 C (-7.1 F)
1976	-29.4 C (-20.9 F)
1977	-26.1 C (-15.0 F)
1978	-21.5 C (-6.7 F)
1979	-26.0 C (-14.8 F)
1980	-26.0 C (-14.8 F)
1981	-25.5 C (-13.9 F)
1982	-25.5 C (-13.9 F)
1983	-22.0 C (-7.6 F)

Wettest day (Rx1day)

The wettest day of the year at St Williams, 1954 to 1983. The record is 110.4 mm (4.3 in) in 1977, marked on the chart; the median year is 54.0 mm (2.1 in).

Wettest day (Rx1day) at St Williams by year
Year	Wettest day (Rx1day)
1954	74.2 mm (2.9 in)
1955	67.1 mm (2.6 in)
1956	37.3 mm (1.5 in)
1957	66.8 mm (2.6 in)
1958	43.2 mm (1.7 in)
1959	58.4 mm (2.3 in)
1960	41.9 mm (1.6 in)
1961	38.1 mm (1.5 in)
1962	47.0 mm (1.9 in)
1963	75.7 mm (3.0 in)
1964	76.7 mm (3.0 in)
1965	54.9 mm (2.2 in)
1966	73.4 mm (2.9 in)
1967	53.1 mm (2.1 in)
1968	87.1 mm (3.4 in)
1969	42.7 mm (1.7 in)
1970	51.6 mm (2.0 in)
1971	50.3 mm (2.0 in)
1972	61.0 mm (2.4 in)
1973	47.8 mm (1.9 in)
1974	38.1 mm (1.5 in)
1975	60.7 mm (2.4 in)
1976	41.7 mm (1.6 in)
1977	110.4 mm (4.3 in)
1978	46.0 mm (1.8 in)
1979	44.4 mm (1.7 in)
1980	88.0 mm (3.5 in)
1981	50.0 mm (2.0 in)
1982	58.5 mm (2.3 in)
1983	60.0 mm (2.4 in)

Wettest five days (Rx5day)

The wettest five days of the year at St Williams, 1954 to 1983. The record is 148.4 mm (5.8 in) in 1966, marked on the chart; the median year is 90.9 mm (3.6 in).

Wettest five days (Rx5day) at St Williams by year
Year	Wettest five days (Rx5day)
1954	115.6 mm (4.6 in)
1955	111.0 mm (4.4 in)
1956	83.3 mm (3.3 in)
1957	97.2 mm (3.8 in)
1958	80.1 mm (3.2 in)
1959	92.5 mm (3.6 in)
1960	62.8 mm (2.5 in)
1961	72.3 mm (2.8 in)
1962	51.1 mm (2.0 in)
1963	90.5 mm (3.6 in)
1964	122.2 mm (4.8 in)
1965	94.8 mm (3.7 in)
1966	148.4 mm (5.8 in)
1967	91.2 mm (3.6 in)
1968	102.9 mm (4.1 in)
1969	78.4 mm (3.1 in)
1970	76.2 mm (3.0 in)
1971	50.8 mm (2.0 in)
1972	72.9 mm (2.9 in)
1973	121.7 mm (4.8 in)
1974	86.6 mm (3.4 in)
1975	87.9 mm (3.5 in)
1976	124.5 mm (4.9 in)
1977	146.0 mm (5.7 in)
1978	90.6 mm (3.6 in)
1979	60.0 mm (2.4 in)
1980	109.2 mm (4.3 in)
1981	74.1 mm (2.9 in)
1982	94.3 mm (3.7 in)
1983	117.9 mm (4.6 in)

Longest dry spell (CDD)

The longest dry spell of the year at St Williams, 1954 to 1983. The record is 30 days in 1969, marked on the chart; the median year is 17 days.

Longest dry spell (CDD) at St Williams by year
Year	Longest dry spell (CDD)
1954	13 days
1955	17 days
1956	14 days
1957	22 days
1958	19 days
1959	16 days
1960	18 days
1961	17 days
1962	24 days
1963	26 days
1964	20 days
1965	18 days
1966	19 days
1967	12 days
1968	17 days
1969	30 days
1970	22 days
1971	13 days
1972	14 days
1973	15 days
1974	14 days
1975	13 days
1976	19 days
1977	19 days
1978	23 days
1979	10 days
1980	15 days
1981	10 days
1982	14 days
1983	20 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

22 years with a frost

Across 22 years with a frost, the median last spring frost at St Williams falls on 18 May and the median first autumn frost on 2 October, which leaves a median of 138 days between them.

Frost dates and growing season at St Williams
Measure	Median, all years	Earliest period	Recent period (1956 to 1981)	Recent against earliest	Fitted trend
Last spring frost	18 May	n/a	18 May	n/a	n/a
First autumn frost	2 October	n/a	2 October	n/a	n/a
Growing days	138 days	n/a	138 days	n/a	n/a

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.

Download the Data

Data for St Williams standing records by year: CSV or JSON. Field meanings are on the data page.
Data for St Williams 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 2026-10-14 (14 October 2026). Records are computed by this site and are not official.

Data as of 2026-10-14. Last revised 14 October 2026 (2026-10-14).