Gravenhurst Weather Records (CA006113000)

Record envelope, standing records and threshold days for Gravenhurst (CA006113000), Ontario, Canada, with 80 years of record.

Key Facts for Gravenhurst

Gravenhurst (CA006113000) is a weather station in Ontario, Canada at 44.92 latitude and -79.37 longitude, 248 m (814 ft) above sea level.
The station reports from 1870 to 1949, 80 years of record.
1,464 records set at Gravenhurst still stand.
Records are tracked for tmax, tmin, prcp, snow: an element needs 30 years of data to be eligible.
Gravenhurst set a daily record precipitation of 61.7 mm (2.4 in) on 9 July 1949.

About the Station

Location: Ontario, Canada, 44.92 latitude, -79.37 longitude.
Elevation: 248 m (814 ft).
Period of record: 1870 to 1949, 80 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 Gravenhurst. 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 Gravenhurst, with 2026 drawn through them
Month	Highest record high	Lowest record low	2026 highest maximum	2026 lowest minimum
Jan	10.6 C (51.1 F)	-44.4 C (-47.9 F)	n/a	n/a
Feb	11.1 C (52.0 F)	-41.7 C (-43.1 F)	n/a	n/a
Mar	21.1 C (70.0 F)	-33.3 C (-27.9 F)	n/a	n/a
Apr	29.4 C (84.9 F)	-21.7 C (-7.1 F)	n/a	n/a
May	35.0 C (95.0 F)	-6.7 C (19.9 F)	n/a	n/a
Jun	34.4 C (93.9 F)	-3.3 C (26.1 F)	n/a	n/a
Jul	36.7 C (98.1 F)	0.6 C (33.1 F)	n/a	n/a
Aug	35.6 C (96.1 F)	-0.6 C (30.9 F)	n/a	n/a
Sep	34.4 C (93.9 F)	-6.1 C (21.0 F)	n/a	n/a
Oct	28.9 C (84.0 F)	-10.6 C (12.9 F)	n/a	n/a
Nov	20.0 C (68.0 F)	-28.3 C (-18.9 F)	n/a	n/a
Dec	13.3 C (55.9 F)	-38.9 C (-38.0 F)	n/a	n/a

Which Years Hold Standing Records

1,464 standing records

1,464 records at Gravenhurst still stand. 1879 holds the most, with 49.

Standing records at Gravenhurst by the year they were set
Year set	Standing records
1875	36
1876	47
1877	39
1878	32
1879	49
1880	39
1881	36
1882	25
1883	33
1884	42
1885	43
1886	34
1887	29
1888	35
1889	25
1890	39
1891	37
1892	23
1893	19
1894	43
1895	37
1896	39
1897	24
1898	31
1899	38
1900	42
1901	18
1902	29
1903	29
1904	28
1905	18
1906	37
1907	25
1908	18
1909	23
1910	24
1911	26
1912	42
1913	38
1914	37
1915	24
1916	13
1918	26
1919	33
1920	40
1921	20

All-Time Record Progression

8 new records

8 all-time records were set at Gravenhurst between 23 February 1907 and 1 February 1949. Each dot is a new record.

When Gravenhurst set new all-time records
Date	Kind	Detail
1907-02-23	Record low minimum temperature	Record low minimum temperature -41.7 C (-43.1 F)
1908-01-30	Record low minimum temperature	Record low minimum temperature -44.4 C (-47.9 F)
1910-02-12	Record daily snowfall	Record daily snowfall 38.1 cm (15.0 in)
1911-07-09	Record high maximum temperature	Record high maximum temperature 36.7 C (98.1 F)
1912-01-11	Record low maximum temperature	Record low maximum temperature -27.8 C (-18.0 F)
1914-01-13	Record low maximum temperature	Record low maximum temperature -28.3 C (-18.9 F)
1914-06-09	Record high minimum temperature	Record high minimum temperature 24.4 C (75.9 F)
1949-02-01	Record daily snowfall	Record daily snowfall 52.1 cm (20.5 in)

Wettest Day of Each Month

Sep: 118.4 mm (4.7 in)

The wettest day on record for each calendar month at Gravenhurst. The most was 118.4 mm (4.7 in) on 13 September 1878.

Record daily precipitation for each month at Gravenhurst
Month	Record daily precipitation (mm)	Date
Jan	36.6 mm (1.4 in)	1 January 1891
Feb	52.1 mm (2.1 in)	1 February 1949
Mar	32.8 mm (1.3 in)	21 March 1886
Apr	29.7 mm (1.2 in)	19 April 1909
May	67.3 mm (2.6 in)	30 May 1908
Jun	73.2 mm (2.9 in)	22 June 1907
Jul	66.0 mm (2.6 in)	5 July 1899
Aug	71.4 mm (2.8 in)	8 August 1892
Sep	118.4 mm (4.7 in)	13 September 1878
Oct	49.5 mm (1.9 in)	14 October 1893
Nov	46.5 mm (1.8 in)	9 November 1870
Dec	38.6 mm (1.5 in)	4 December 1887

Period of Record Coverage

1875 to 1921

46 years of record at Gravenhurst, 1875 to 1921. 3 years have data for under 90 percent of days and are left out of rankings: 1875, 1916, 1921.

Days with data per year at Gravenhurst
Year	Days with data	Share of year	Complete
1875	144	39%	No
1876	366	100%	Yes
1877	365	100%	Yes
1878	362	99%	Yes
1879	363	99%	Yes
1880	364	99%	Yes
1881	364	100%	Yes
1882	364	100%	Yes
1883	364	100%	Yes
1884	365	100%	Yes
1885	364	100%	Yes
1886	365	100%	Yes
1887	363	99%	Yes
1888	360	98%	Yes
1889	363	99%	Yes
1890	363	99%	Yes
1891	365	100%	Yes
1892	366	100%	Yes
1893	365	100%	Yes
1894	365	100%	Yes
1895	365	100%	Yes
1896	366	100%	Yes
1897	365	100%	Yes
1898	365	100%	Yes
1899	365	100%	Yes
1900	365	100%	Yes
1901	365	100%	Yes
1902	365	100%	Yes
1903	365	100%	Yes
1904	366	100%	Yes
1905	365	100%	Yes
1906	365	100%	Yes
1907	365	100%	Yes
1908	366	100%	Yes
1909	365	100%	Yes
1910	365	100%	Yes
1911	365	100%	Yes
1912	366	100%	Yes
1913	365	100%	Yes
1914	364	100%	Yes
1915	334	92%	Yes
1916	120	33%	No
1918	334	92%	Yes
1919	364	100%	Yes
1920	366	100%	Yes
1921	158	43%	No

Latest Records

Latest records at Gravenhurst
Date	Station	Record	Value	Beat old record by	Old record stood	Significance
9 July 1949	Gravenhurst, CA	daily rain	61.7 mm (2.4 in)	37.6 mm (1.5 in)	44 years	58 of 100 (Notable)
18 April 1949	Gravenhurst, CA	daily rain (Tie)	9.7 mm (0.38 in)	tie	48 years	5 of 100 (Routine)
15 April 1949	Gravenhurst, CA	daily rain	18.5 mm (0.7 in)	8.3 mm (0.33 in)	36 years	20 of 100 (Routine)
15 April 1949	Gravenhurst, CA	daily snowfall (Tie)	5.1 cm (2.0 in)	tie	55 years	6 of 100 (Routine)
13 February 1949	Gravenhurst, CA	daily snowfall	9.7 cm (3.8 in)	4.6 cm (1.8 in)	52 years	32 of 100 (Routine)
2 February 1949	Gravenhurst, CA	daily snowfall	12.7 cm (5.0 in)	2.5 cm (1.0 in)	66 years	33 of 100 (Routine)
2 February 1949	Gravenhurst, CA	daily rain	12.7 mm (0.5 in)	2.5 mm (0.10 in)	66 years	20 of 100 (Routine)
1 February 1949	Gravenhurst, CA	all-time snowfall	52.1 cm (20.5 in)	14.0 cm (5.5 in)	38 years	68 of 100 (Major)
1 February 1949	Gravenhurst, CA	monthly rain	52.1 mm (2.1 in)	1.3 mm (0.05 in)	61 years	38 of 100 (Notable)
11 August 1948	Gravenhurst, CA	daily rain	48.8 mm (1.9 in)	18.6 mm (0.7 in)	55 years	40 of 100 (Notable)
29 June 1921	Gravenhurst, CA	monthly high max (Tie)	34.4 C (93.9 F)	tie	33 years	5 of 100 (Routine)
28 June 1921	Gravenhurst, CA	daily high min	20.0 C (68.0 F)	0.6 C (1.1 F)	20 years	11 of 100 (Routine)
23 June 1921	Gravenhurst, CA	daily high min (Tie)	17.8 C (64.0 F)	tie	36 years	3 of 100 (Routine)
17 June 1921	Gravenhurst, CA	daily rain	14.5 mm (0.6 in)	6.6 mm (0.26 in)	28 years	19 of 100 (Routine)
10 June 1921	Gravenhurst, CA	daily rain	23.1 mm (0.9 in)	2.8 mm (0.11 in)	37 years	18 of 100 (Routine)
10 June 1921	Gravenhurst, CA	daily high max	31.7 C (89.1 F)	0.6 C (1.1 F)	25 years	12 of 100 (Routine)
29 May 1921	Gravenhurst, CA	daily high min	17.8 C (64.0 F)	2.8 C (5.0 F)	12 years	12 of 100 (Routine)
20 May 1921	Gravenhurst, CA	monthly high max	35.0 C (95.0 F)	2.8 C (5.0 F)	1 year	18 of 100 (Routine)
20 May 1921	Gravenhurst, CA	monthly high min (Tie)	18.3 C (64.9 F)	tie	25 years	5 of 100 (Routine)
27 April 1921	Gravenhurst, CA	monthly high min (Tie)	12.8 C (55.0 F)	tie	43 years	6 of 100 (Routine)

Climate Trend

41 complete years, 1876 to 1920

One stripe for each of 41 complete years at Gravenhurst, 1876 to 1920. Blue stripes are years cooler than the station's own mean of 5.2 C (41.4 F); red stripes are warmer. The coolest year was 1885, at 3.4 C (38.1 F), and the warmest was 1878, at 6.8 C (44.2 F). The strongest colour marks a difference of 1.9 C (3.4 F).

Annual mean temperature at Gravenhurst as warming stripes, 1876 to 1920
Year	Annual mean temperature	Difference from the station mean
1876	4.4 C	-0.82 C
1877	5.8 C	+0.63 C
1878	6.8 C	+1.56 C
1879	4.5 C	-0.74 C
1880	5.6 C	+0.38 C
1881	6.0 C	+0.75 C
1882	5.5 C	+0.31 C
1883	3.7 C	-1.48 C
1884	5.1 C	-0.11 C
1885	3.4 C	-1.81 C
1886	4.9 C	-0.35 C
1887	5.2 C	+0.04 C
1888	4.2 C	-1.01 C
1889	5.9 C	+0.67 C
1890	5.7 C	+0.47 C
1891	6.3 C	+1.09 C
1892	5.2 C	+0.03 C
1893	4.5 C	-0.75 C
1894	6.4 C	+1.21 C
1895	5.2 C	+0.04 C
1896	5.4 C	+0.19 C
1897	5.7 C	+0.51 C
1898	6.8 C	+1.55 C
1899	5.3 C	+0.07 C
1900	6.0 C	+0.82 C
1901	5.7 C	+0.52 C
1902	5.7 C	+0.48 C
1903	5.6 C	+0.42 C
1904	3.4 C	-1.76 C
1905	4.6 C	-0.60 C
1906	5.6 C	+0.39 C
1907	4.0 C	-1.21 C
1908	5.1 C	-0.12 C
1909	4.7 C	-0.50 C
1910	4.8 C	-0.41 C
1911	5.3 C	+0.05 C
1912	3.6 C	-1.64 C
1913	5.8 C	+0.55 C
1914	4.5 C	-0.73 C
1919	6.3 C	+1.09 C
1920	5.3 C	+0.09 C

The fitted trend in annual mean temperature here over 1876 to 1920 is -0.04 C (-0.26 to 0.19) per decade. The interval includes zero, so the trend is not clearly different from zero. In Fahrenheit: -0.1 F (-0.5 to 0.3) 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 Gravenhurst
Measure	Per decade (C)	Per decade (F)	Period	Complete years	Reading
Annual mean temperature	-0.04 C (-0.26 to 0.19) per decade	-0.1 F (-0.5 to 0.3) per decade	1876 to 1920	41	Not clearly different from zero
Mean daily maximum	0.1 C (-0.1 to 0.3) per decade	0.2 F (-0.2 to 0.6) per decade	1876 to 1920	41	Not clearly different from zero
Mean daily minimum	-0.2 C (-0.4 to 0.1) per decade	-0.3 F (-0.8 to 0.2) per decade	1876 to 1920	41	Not clearly different from zero

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

1870 to 1949

Yearly extremes at Gravenhurst: 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)	1911	33.3 C (91.9 F)	46
Coldest night (TNn)	-44.4 C (-47.9 F)	1908	-35.0 C (-31.0 F)	46
Wettest day (Rx1day)	118.4 mm (4.7 in)	1878	46.7 mm (1.8 in)	53
Wettest five days (Rx5day)	175.3 mm (6.9 in)	1878	69.7 mm (2.7 in)	53
Longest dry spell (CDD)	35 days	1881	16 days	53

Hottest day (TXx)

The hottest day of the year at Gravenhurst, 1870 to 1949. The record is 36.7 C (98.1 F) in 1911, marked on the chart; the median year is 33.3 C (91.9 F).

Hottest day (TXx) at Gravenhurst by year
Year	Hottest day (TXx)
1870	n/a
1871	n/a
1872	n/a
1873	n/a
1874	n/a
1875	31.1 C (88.0 F)
1876	33.3 C (91.9 F)
1877	32.8 C (91.0 F)
1878	33.9 C (93.0 F)
1879	31.7 C (89.1 F)
1880	31.7 C (89.1 F)
1881	35.0 C (95.0 F)
1882	32.8 C (91.0 F)
1883	30.6 C (87.1 F)
1884	33.3 C (91.9 F)
1885	30.6 C (87.1 F)
1886	32.8 C (91.0 F)
1887	33.9 C (93.0 F)
1888	34.4 C (93.9 F)
1889	32.8 C (91.0 F)
1890	33.3 C (91.9 F)
1891	33.9 C (93.0 F)
1892	35.0 C (95.0 F)
1893	32.2 C (90.0 F)
1894	34.4 C (93.9 F)
1895	33.3 C (91.9 F)
1896	32.2 C (90.0 F)
1897	36.1 C (97.0 F)
1898	34.4 C (93.9 F)
1899	35.0 C (95.0 F)
1900	33.3 C (91.9 F)
1901	35.0 C (95.0 F)
1902	29.4 C (84.9 F)
1903	33.3 C (91.9 F)
1904	31.1 C (88.0 F)
1905	30.6 C (87.1 F)
1906	32.2 C (90.0 F)
1907	31.7 C (89.1 F)
1908	32.8 C (91.0 F)
1909	30.6 C (87.1 F)
1910	31.7 C (89.1 F)
1911	36.7 C (98.1 F)
1912	33.3 C (91.9 F)
1913	33.9 C (93.0 F)
1914	35.0 C (95.0 F)
1915	30.6 C (87.1 F)
1916	20.6 C (69.1 F)
1918	35.6 C (96.1 F)
1919	34.4 C (93.9 F)
1920	32.2 C (90.0 F)
1921	35.0 C (95.0 F)
1948	n/a
1949	n/a

Coldest night (TNn)

The coldest night of the year at Gravenhurst, 1870 to 1949. The record is -44.4 C (-47.9 F) in 1908, marked on the chart; the median year is -35.0 C (-31.0 F).

Coldest night (TNn) at Gravenhurst by year
Year	Coldest night (TNn)
1870	n/a
1871	n/a
1872	n/a
1873	n/a
1874	n/a
1875	-35.6 C (-32.1 F)
1876	-32.8 C (-27.0 F)
1877	-32.8 C (-27.0 F)
1878	-28.9 C (-20.0 F)
1879	-34.4 C (-29.9 F)
1880	-26.1 C (-15.0 F)
1881	-35.0 C (-31.0 F)
1882	-35.6 C (-32.1 F)
1883	-34.4 C (-29.9 F)
1884	-38.9 C (-38.0 F)
1885	-35.6 C (-32.1 F)
1886	-37.8 C (-36.0 F)
1887	-35.0 C (-31.0 F)
1888	-33.9 C (-29.0 F)
1889	-34.4 C (-29.9 F)
1890	-28.3 C (-18.9 F)
1891	-30.6 C (-23.1 F)
1892	-34.4 C (-29.9 F)
1893	-34.4 C (-29.9 F)
1894	-35.6 C (-32.1 F)
1895	-35.6 C (-32.1 F)
1896	-37.8 C (-36.0 F)
1897	-33.3 C (-27.9 F)
1898	-35.0 C (-31.0 F)
1899	-38.9 C (-38.0 F)
1900	-38.3 C (-36.9 F)
1901	-33.3 C (-27.9 F)
1902	-28.3 C (-18.9 F)
1903	-31.1 C (-24.0 F)
1904	-36.7 C (-34.1 F)
1905	-36.1 C (-33.0 F)
1906	-35.6 C (-32.1 F)
1907	-41.7 C (-43.1 F)
1908	-44.4 C (-47.9 F)
1909	-30.0 C (-22.0 F)
1910	-36.1 C (-33.0 F)
1911	-32.8 C (-27.0 F)
1912	-44.4 C (-47.9 F)
1913	-38.3 C (-36.9 F)
1914	-41.1 C (-42.0 F)
1915	-36.7 C (-34.1 F)
1916	-35.0 C (-31.0 F)
1918	-36.7 C (-34.1 F)
1919	-34.4 C (-29.9 F)
1920	-36.7 C (-34.1 F)
1921	-34.4 C (-29.9 F)
1948	n/a
1949	n/a

Wettest day (Rx1day)

The wettest day of the year at Gravenhurst, 1870 to 1949. The record is 118.4 mm (4.7 in) in 1878, marked on the chart; the median year is 46.7 mm (1.8 in).

Wettest day (Rx1day) at Gravenhurst by year
Year	Wettest day (Rx1day)
1870	46.5 mm (1.8 in)
1871	34.8 mm (1.4 in)
1872	42.9 mm (1.7 in)
1873	48.3 mm (1.9 in)
1874	34.5 mm (1.4 in)
1875	68.3 mm (2.7 in)
1876	33.8 mm (1.3 in)
1877	39.1 mm (1.5 in)
1878	118.4 mm (4.7 in)
1879	43.2 mm (1.7 in)
1880	52.3 mm (2.1 in)
1881	48.5 mm (1.9 in)
1882	53.3 mm (2.1 in)
1883	49.5 mm (1.9 in)
1884	45.7 mm (1.8 in)
1885	53.1 mm (2.1 in)
1886	34.0 mm (1.3 in)
1887	50.8 mm (2.0 in)
1888	46.2 mm (1.8 in)
1889	38.1 mm (1.5 in)
1890	31.8 mm (1.3 in)
1891	40.1 mm (1.6 in)
1892	71.4 mm (2.8 in)
1893	49.5 mm (1.9 in)
1894	40.9 mm (1.6 in)
1895	54.9 mm (2.2 in)
1896	53.1 mm (2.1 in)
1897	50.8 mm (2.0 in)
1898	41.1 mm (1.6 in)
1899	66.0 mm (2.6 in)
1900	31.2 mm (1.2 in)
1901	53.8 mm (2.1 in)
1902	31.8 mm (1.3 in)
1903	27.7 mm (1.1 in)
1904	30.0 mm (1.2 in)
1905	42.9 mm (1.7 in)
1906	55.9 mm (2.2 in)
1907	73.2 mm (2.9 in)
1908	67.3 mm (2.6 in)
1909	36.3 mm (1.4 in)
1910	48.3 mm (1.9 in)
1911	54.4 mm (2.1 in)
1912	30.2 mm (1.2 in)
1913	38.1 mm (1.5 in)
1914	26.9 mm (1.1 in)
1915	50.3 mm (2.0 in)
1916	25.9 mm (1.0 in)
1918	46.7 mm (1.8 in)
1919	46.7 mm (1.8 in)
1920	69.9 mm (2.8 in)
1921	23.1 mm (0.9 in)
1948	48.8 mm (1.9 in)
1949	61.7 mm (2.4 in)

Wettest five days (Rx5day)

The wettest five days of the year at Gravenhurst, 1870 to 1949. The record is 175.3 mm (6.9 in) in 1878, marked on the chart; the median year is 69.7 mm (2.7 in).

Wettest five days (Rx5day) at Gravenhurst by year
Year	Wettest five days (Rx5day)
1870	53.3 mm (2.1 in)
1871	48.3 mm (1.9 in)
1872	51.0 mm (2.0 in)
1873	66.8 mm (2.6 in)
1874	72.6 mm (2.9 in)
1875	71.3 mm (2.8 in)
1876	72.4 mm (2.9 in)
1877	65.1 mm (2.6 in)
1878	175.3 mm (6.9 in)
1879	56.9 mm (2.2 in)
1880	76.2 mm (3.0 in)
1881	84.0 mm (3.3 in)
1882	57.1 mm (2.2 in)
1883	70.8 mm (2.8 in)
1884	64.1 mm (2.5 in)
1885	53.6 mm (2.1 in)
1886	64.2 mm (2.5 in)
1887	96.6 mm (3.8 in)
1888	66.8 mm (2.6 in)
1889	79.7 mm (3.1 in)
1890	42.0 mm (1.7 in)
1891	62.0 mm (2.4 in)
1892	131.5 mm (5.2 in)
1893	59.2 mm (2.3 in)
1894	77.5 mm (3.1 in)
1895	57.9 mm (2.3 in)
1896	116.3 mm (4.6 in)
1897	84.3 mm (3.3 in)
1898	56.6 mm (2.2 in)
1899	88.1 mm (3.5 in)
1900	69.7 mm (2.7 in)
1901	74.1 mm (2.9 in)
1902	60.2 mm (2.4 in)
1903	73.9 mm (2.9 in)
1904	46.5 mm (1.8 in)
1905	71.9 mm (2.8 in)
1906	91.9 mm (3.6 in)
1907	108.2 mm (4.3 in)
1908	86.6 mm (3.4 in)
1909	77.2 mm (3.0 in)
1910	57.5 mm (2.3 in)
1911	59.2 mm (2.3 in)
1912	49.8 mm (2.0 in)
1913	58.9 mm (2.3 in)
1914	53.8 mm (2.1 in)
1915	108.4 mm (4.3 in)
1916	50.3 mm (2.0 in)
1918	70.1 mm (2.8 in)
1919	82.6 mm (3.3 in)
1920	70.9 mm (2.8 in)
1921	30.5 mm (1.2 in)
1948	58.2 mm (2.3 in)
1949	81.0 mm (3.2 in)

Longest dry spell (CDD)

The longest dry spell of the year at Gravenhurst, 1870 to 1949. The record is 35 days in 1881, marked on the chart; the median year is 16 days.

Longest dry spell (CDD) at Gravenhurst by year
Year	Longest dry spell (CDD)
1870	12 days
1871	20 days
1872	18 days
1873	13 days
1874	24 days
1875	14 days
1876	14 days
1877	16 days
1878	13 days
1879	20 days
1880	15 days
1881	35 days
1882	12 days
1883	11 days
1884	21 days
1885	14 days
1886	18 days
1887	26 days
1888	33 days
1889	26 days
1890	14 days
1891	26 days
1892	15 days
1893	11 days
1894	12 days
1895	13 days
1896	12 days
1897	14 days
1898	15 days
1899	13 days
1900	15 days
1901	17 days
1902	15 days
1903	20 days
1904	23 days
1905	14 days
1906	16 days
1907	16 days
1908	29 days
1909	16 days
1910	25 days
1911	16 days
1912	17 days
1913	13 days
1914	17 days
1915	19 days
1916	13 days
1918	17 days
1919	17 days
1920	21 days
1921	14 days
1948	14 days
1949	24 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

41 years with a frost

Across 41 years with a frost, the median last spring frost at Gravenhurst falls on 21 May and the median first autumn frost on 28 September, which leaves a median of 128 days between them.

Fitted over all years, the growing season changes by -1.1 days per decade at this station.

Frost dates and growing season at Gravenhurst
Measure	Median, all years	Earliest period	Recent period (1887 to 1920)	Recent against earliest	Fitted trend
Last spring frost	21 May	n/a	20 May	n/a	-1.1 days per decade
First autumn frost	28 September	n/a	26 September	n/a	-2.2 days per decade
Growing days	128 days	n/a	129 days	n/a	-1.1 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

46 years, 1871 to 1920

A day with at least 45.5 mm (1.8 in) of rain is expected about once in 2 years. A day with at least 98.5 mm (3.9 in) of rain is expected about once in 100 years.

Rainfall return levels at Gravenhurst: the daily rain expected about once in a given number of years
Expected about once in	A day with at least	Note
2 years	45.5 mm (1.8 in)
5 years	58.8 mm (2.3 in)
10 years	67.9 mm (2.7 in)
25 years	79.9 mm (3.1 in)
50 years	89.1 mm (3.5 in)	Longer than the 46 years of record
100 years	98.5 mm (3.9 in)	Longer than the 46 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, 46 years of values from 1871 to 1920.

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: 118.4 mm (4.7 in) in 1878; 73.2 mm (2.9 in) in 1907; 71.4 mm (2.8 in) in 1892.

Station Changes

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

Download the Data

Data for Gravenhurst standing records by year: CSV or JSON. Field meanings are on the data page.
Data for Gravenhurst 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 2026-10-17. Last revised 17 October 2026 (2026-10-17).