Thunder Bay Wpcp Weather Records (CA00604HBFA)

Record envelope, standing records and threshold days for Thunder Bay Wpcp (CA00604HBFA), Ontario, Canada, with 30 years of record.

Key Facts for Thunder Bay Wpcp

Thunder Bay Wpcp (CA00604HBFA) is a weather station in Ontario, Canada at 48.40 latitude and -89.23 longitude, 184 m (604 ft) above sea level.
The station reports from 1960 to 1989, 30 years of record.
1,464 records set at Thunder Bay Wpcp still stand.
Records are tracked for no element yet: an element needs 30 years of data to be eligible.

About the Station

Location: Ontario, Canada, 48.40 latitude, -89.23 longitude.
Elevation: 184 m (604 ft).
Period of record: 1960 to 1989, 30 years.
Eligible elements: none yet.

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 Thunder Bay Wpcp. 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 Thunder Bay Wpcp, with 2026 drawn through them
Month	Highest record high	Lowest record low	2026 highest maximum	2026 lowest minimum
Jan	7.8 C (46.0 F)	-38.5 C (-37.3 F)	n/a	n/a
Feb	12.8 C (55.0 F)	-38.0 C (-36.4 F)	n/a	n/a
Mar	17.2 C (63.0 F)	-31.7 C (-25.1 F)	n/a	n/a
Apr	28.3 C (82.9 F)	-19.0 C (-2.2 F)	n/a	n/a
May	34.0 C (93.2 F)	-10.6 C (12.9 F)	n/a	n/a
Jun	33.3 C (91.9 F)	-1.7 C (28.9 F)	n/a	n/a
Jul	33.9 C (93.0 F)	1.1 C (34.0 F)	n/a	n/a
Aug	37.0 C (98.6 F)	0.6 C (33.1 F)	n/a	n/a
Sep	30.6 C (87.1 F)	-7.5 C (18.5 F)	n/a	n/a
Oct	25.0 C (77.0 F)	-13.0 C (8.6 F)	n/a	n/a
Nov	21.7 C (71.1 F)	-27.2 C (-17.0 F)	n/a	n/a
Dec	11.5 C (52.7 F)	-34.0 C (-29.2 F)	n/a	n/a

Which Years Hold Standing Records

1,464 standing records

1,464 records at Thunder Bay Wpcp still stand. 1964 holds the most, with 96.

Standing records at Thunder Bay Wpcp by the year they were set
Year set	Standing records
1960	12
1961	57
1962	72
1963	89
1964	96
1965	78
1966	67
1967	77
1968	67
1969	60
1970	59
1971	48
1972	52
1973	55
1974	50
1975	52
1976	69
1977	55
1978	40
1979	56
1980	66
1981	74
1982	48
1983	65

Wettest Day of Each Month

Sep: 125.5 mm (4.9 in)

The wettest day on record for each calendar month at Thunder Bay Wpcp. The most was 125.5 mm (4.9 in) on 8 September 1977.

Record daily precipitation for each month at Thunder Bay Wpcp
Month	Record daily precipitation (mm)	Date
Jan	49.5 mm (1.9 in)	10 January 1975
Feb	27.9 mm (1.1 in)	13 February 1962
Mar	31.0 mm (1.2 in)	12 March 1977
Apr	43.9 mm (1.7 in)	21 April 1964
May	55.4 mm (2.2 in)	23 May 1971
Jun	41.4 mm (1.6 in)	9 June 1963
Jul	71.4 mm (2.8 in)	7 July 1962
Aug	58.2 mm (2.3 in)	19 August 1973
Sep	125.5 mm (4.9 in)	8 September 1977
Oct	44.5 mm (1.8 in)	27 October 1970
Nov	45.0 mm (1.8 in)	20 November 1973
Dec	35.6 mm (1.4 in)	8 December 1977

Period of Record Coverage

1960 to 1983

24 years of record at Thunder Bay Wpcp, 1960 to 1983. 1 years have data for under 90 percent of days and are left out of rankings: 1960.

Days with data per year at Thunder Bay Wpcp
Year	Days with data	Share of year	Complete
1960	92	25%	No
1961	365	100%	Yes
1962	363	99%	Yes
1963	363	99%	Yes
1964	366	100%	Yes
1965	364	100%	Yes
1966	365	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	365	100%	Yes
1974	365	100%	Yes
1975	365	100%	Yes
1976	366	100%	Yes
1977	365	100%	Yes
1978	365	100%	Yes
1979	365	100%	Yes
1980	366	100%	Yes
1981	365	100%	Yes
1982	363	99%	Yes
1983	357	98%	Yes

Latest Records

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

Climate Trend

23 complete years, 1961 to 1983

One stripe for each of 23 complete years at Thunder Bay Wpcp, 1961 to 1983. Blue stripes are years cooler than the station's own mean of 2.6 C (36.6 F); red stripes are warmer. The coolest year was 1972, at 1.1 C (34.0 F), and the warmest was 1981, at 3.8 C (38.9 F). The strongest colour marks a difference of 1.5 C (2.7 F).

Annual mean temperature at Thunder Bay Wpcp as warming stripes, 1961 to 1983
Year	Annual mean temperature	Difference from the station mean
1961	3.2 C	+0.69 C
1962	2.3 C	-0.22 C
1963	2.3 C	-0.25 C
1964	2.6 C	+0.06 C
1965	1.9 C	-0.63 C
1966	2.3 C	-0.23 C
1967	2.0 C	-0.60 C
1968	3.0 C	+0.42 C
1969	3.0 C	+0.48 C
1970	2.7 C	+0.15 C
1971	2.9 C	+0.38 C
1972	1.1 C	-1.43 C
1973	3.6 C	+1.03 C
1974	2.1 C	-0.48 C
1975	3.1 C	+0.58 C
1976	2.3 C	-0.23 C
1977	3.4 C	+0.86 C
1978	2.1 C	-0.49 C
1979	1.6 C	-0.95 C
1980	2.6 C	+0.02 C
1981	3.8 C	+1.26 C
1982	1.7 C	-0.90 C
1983	3.1 C	+0.59 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

1960 to 1983

Yearly extremes at Thunder Bay Wpcp: the record and the median year
Measure	Record	Year of the record	Median year	Years with a value
Hottest day (TXx)	37.0 C (98.6 F)	1983	32.0 C (89.5 F)	24
Coldest night (TNn)	-38.5 C (-37.3 F)	1982	-34.5 C (-30.1 F)	24
Wettest day (Rx1day)	125.5 mm (4.9 in)	1977	41.8 mm (1.6 in)	24
Wettest five days (Rx5day)	133.9 mm (5.3 in)	1977	67.4 mm (2.7 in)	24
Longest dry spell (CDD)	30 days	1968	19 days	24

Hottest day (TXx)

The hottest day of the year at Thunder Bay Wpcp, 1960 to 1983. The record is 37.0 C (98.6 F) in 1983, marked on the chart; the median year is 32.0 C (89.5 F).

Hottest day (TXx) at Thunder Bay Wpcp by year
Year	Hottest day (TXx)
1960	22.8 C (73.0 F)
1961	30.0 C (86.0 F)
1962	29.4 C (84.9 F)
1963	31.7 C (89.1 F)
1964	32.2 C (90.0 F)
1965	32.8 C (91.0 F)
1966	33.9 C (93.0 F)
1967	27.8 C (82.0 F)
1968	31.1 C (88.0 F)
1969	32.2 C (90.0 F)
1970	33.3 C (91.9 F)
1971	31.1 C (88.0 F)
1972	31.1 C (88.0 F)
1973	30.0 C (86.0 F)
1974	33.3 C (91.9 F)
1975	32.2 C (90.0 F)
1976	31.1 C (88.0 F)
1977	33.3 C (91.9 F)
1978	29.5 C (85.1 F)
1979	32.5 C (90.5 F)
1980	34.0 C (93.2 F)
1981	32.5 C (90.5 F)
1982	28.5 C (83.3 F)
1983	37.0 C (98.6 F)

Coldest night (TNn)

The coldest night of the year at Thunder Bay Wpcp, 1960 to 1983. The record is -38.5 C (-37.3 F) in 1982, marked on the chart; the median year is -34.5 C (-30.1 F).

Coldest night (TNn) at Thunder Bay Wpcp by year
Year	Coldest night (TNn)
1960	-28.9 C (-20.0 F)
1961	-33.9 C (-29.0 F)
1962	-35.6 C (-32.1 F)
1963	-37.2 C (-35.0 F)
1964	-31.7 C (-25.1 F)
1965	-35.0 C (-31.0 F)
1966	-35.6 C (-32.1 F)
1967	-37.2 C (-35.0 F)
1968	-35.6 C (-32.1 F)
1969	-27.2 C (-17.0 F)
1970	-36.1 C (-33.0 F)
1971	-32.8 C (-27.0 F)
1972	-36.7 C (-34.1 F)
1973	-31.1 C (-24.0 F)
1974	-35.0 C (-31.0 F)
1975	-33.9 C (-29.0 F)
1976	-32.2 C (-26.0 F)
1977	-33.9 C (-29.0 F)
1978	-32.2 C (-26.0 F)
1979	-38.0 C (-36.4 F)
1980	-31.0 C (-23.8 F)
1981	-36.0 C (-32.8 F)
1982	-38.5 C (-37.3 F)
1983	-34.0 C (-29.2 F)

Wettest day (Rx1day)

The wettest day of the year at Thunder Bay Wpcp, 1960 to 1983. The record is 125.5 mm (4.9 in) in 1977, marked on the chart; the median year is 41.8 mm (1.6 in).

Wettest day (Rx1day) at Thunder Bay Wpcp by year
Year	Wettest day (Rx1day)
1960	25.9 mm (1.0 in)
1961	73.2 mm (2.9 in)
1962	71.4 mm (2.8 in)
1963	41.4 mm (1.6 in)
1964	43.9 mm (1.7 in)
1965	42.2 mm (1.7 in)
1966	29.0 mm (1.1 in)
1967	27.4 mm (1.1 in)
1968	49.8 mm (2.0 in)
1969	23.1 mm (0.9 in)
1970	44.5 mm (1.8 in)
1971	55.4 mm (2.2 in)
1972	32.3 mm (1.3 in)
1973	58.2 mm (2.3 in)
1974	33.5 mm (1.3 in)
1975	49.5 mm (1.9 in)
1976	36.6 mm (1.4 in)
1977	125.5 mm (4.9 in)
1978	26.5 mm (1.0 in)
1979	38.0 mm (1.5 in)
1980	54.0 mm (2.1 in)
1981	39.2 mm (1.5 in)
1982	67.3 mm (2.6 in)
1983	40.6 mm (1.6 in)

Wettest five days (Rx5day)

The wettest five days of the year at Thunder Bay Wpcp, 1960 to 1983. The record is 133.9 mm (5.3 in) in 1977, marked on the chart; the median year is 67.4 mm (2.7 in).

Wettest five days (Rx5day) at Thunder Bay Wpcp by year
Year	Wettest five days (Rx5day)
1960	32.8 mm (1.3 in)
1961	110.3 mm (4.3 in)
1962	80.8 mm (3.2 in)
1963	62.5 mm (2.5 in)
1964	89.1 mm (3.5 in)
1965	63.5 mm (2.5 in)
1966	51.3 mm (2.0 in)
1967	45.0 mm (1.8 in)
1968	96.8 mm (3.8 in)
1969	48.3 mm (1.9 in)
1970	82.6 mm (3.3 in)
1971	125.0 mm (4.9 in)
1972	48.2 mm (1.9 in)
1973	73.4 mm (2.9 in)
1974	49.5 mm (1.9 in)
1975	56.9 mm (2.2 in)
1976	64.8 mm (2.6 in)
1977	133.9 mm (5.3 in)
1978	62.2 mm (2.4 in)
1979	84.8 mm (3.3 in)
1980	74.6 mm (2.9 in)
1981	70.1 mm (2.8 in)
1982	107.4 mm (4.2 in)
1983	58.7 mm (2.3 in)

Longest dry spell (CDD)

The longest dry spell of the year at Thunder Bay Wpcp, 1960 to 1983. The record is 30 days in 1968, marked on the chart; the median year is 19 days.

Longest dry spell (CDD) at Thunder Bay Wpcp by year
Year	Longest dry spell (CDD)
1960	14 days
1961	27 days
1962	17 days
1963	22 days
1964	15 days
1965	24 days
1966	15 days
1967	19 days
1968	30 days
1969	23 days
1970	20 days
1971	20 days
1972	18 days
1973	21 days
1974	13 days
1975	19 days
1976	18 days
1977	20 days
1978	24 days
1979	19 days
1980	14 days
1981	17 days
1982	17 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

23 years with a frost

Across 23 years with a frost, the median last spring frost at Thunder Bay Wpcp falls on 26 May and the median first autumn frost on 16 September, which leaves a median of 110 days between them.

Frost dates and growing season at Thunder Bay Wpcp
Measure	Median, all years	Earliest period	Recent period (1961 to 1983)	Recent against earliest	Fitted trend
Last spring frost	26 May	n/a	26 May	n/a	n/a
First autumn frost	16 September	n/a	16 September	n/a	n/a
Growing days	110 days	n/a	110 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 Thunder Bay Wpcp standing records by year: CSV or JSON. Field meanings are on the data page.
Data for Thunder Bay Wpcp 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).