Ariel Dam Weather Records (USC00450242)

Record envelope, standing records and threshold days for Ariel Dam (USC00450242), Washington, United States, with 42 years of record.

Key Facts for Ariel Dam

Ariel Dam (USC00450242) is a weather station in Washington, United States at 45.95 latitude and -122.55 longitude, 68 m (224 ft) above sea level.
The station reports from 1930 to 1971, 42 years of record.
1,188 records set at Ariel Dam still stand.
Records are tracked for prcp: an element needs 30 years of data to be eligible.
Ariel Dam set a daily record precipitation of 43.9 mm (1.7 in) on 19 October 1971.

About the Station

Location: Washington, United States, 45.95 latitude, -122.55 longitude.
Elevation: 68 m (224 ft).
Period of record: 1930 to 1971, 42 years.
Eligible elements: 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 Ariel Dam. 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 Ariel Dam, with 2026 drawn through them
Month	Highest record high	Lowest record low	2026 highest maximum	2026 lowest minimum
Jan	17.8 C (64.0 F)	-11.1 C (12.0 F)	n/a	n/a
Feb	n/a	n/a	n/a	n/a
Mar	n/a	n/a	n/a	n/a
Apr	26.7 C (80.1 F)	2.2 C (36.0 F)	n/a	n/a
May	28.3 C (82.9 F)	1.1 C (34.0 F)	n/a	n/a
Jun	34.4 C (93.9 F)	1.7 C (35.1 F)	n/a	n/a
Jul	36.1 C (97.0 F)	3.9 C (39.0 F)	n/a	n/a
Aug	37.8 C (100.0 F)	5.6 C (42.1 F)	n/a	n/a
Sep	35.6 C (96.1 F)	1.7 C (35.1 F)	n/a	n/a
Oct	27.8 C (82.0 F)	-1.1 C (30.0 F)	n/a	n/a
Nov	18.3 C (64.9 F)	-4.4 C (24.1 F)	n/a	n/a
Dec	16.1 C (61.0 F)	-3.9 C (25.0 F)	n/a	n/a

Which Years Hold Standing Records

1,188 standing records

1,188 records at Ariel Dam still stand. 1930 holds the most, with 367.

Wettest Day of Each Month

Nov: 111.8 mm (4.4 in)

The wettest day on record for each calendar month at Ariel Dam. The most was 111.8 mm (4.4 in) on 20 November 1962.

Record daily precipitation for each month at Ariel Dam
Month	Record daily precipitation (mm)	Date
Jan	83.6 mm (3.3 in)	22 January 1954
Feb	99.1 mm (3.9 in)	10 February 1949
Mar	76.2 mm (3.0 in)	9 March 1966
Apr	47.8 mm (1.9 in)	27 April 1962
May	49.5 mm (1.9 in)	15 May 1959
Jun	54.6 mm (2.1 in)	2 June 1968
Jul	47.5 mm (1.9 in)	3 July 1966
Aug	75.7 mm (3.0 in)	3 August 1956
Sep	56.4 mm (2.2 in)	4 September 1945
Oct	64.0 mm (2.5 in)	11 October 1959
Nov	111.8 mm (4.4 in)	20 November 1962
Dec	88.9 mm (3.5 in)	22 December 1933

Period of Record Coverage

1930 to 1971

8 years of record at Ariel Dam, 1930 to 1971. 8 years have data for under 90 percent of days and are left out of rankings: 1930, 1935, 1936, 1937, 1938, 1965, 1966, 1971.

Latest Records

Latest records at Ariel Dam
Date	Station	Record	Value	Beat old record by	Old record stood	Significance
19 October 1971	Ariel Dam, US	daily rain	43.9 mm (1.7 in)	20.3 mm (0.8 in)	12 years	24 of 100 (Routine)
29 September 1971	Ariel Dam, US	daily rain	34.0 mm (1.3 in)	13.9 mm (0.5 in)	8 years	19 of 100 (Routine)
1 September 1971	Ariel Dam, US	daily rain	28.7 mm (1.1 in)	12.7 mm (0.5 in)	32 years	25 of 100 (Routine)
1 August 1971	Ariel Dam, US	daily rain	2.0 mm (0.08 in)	0.2 mm (0.01 in)	6 years	6 of 100 (Routine)
25 June 1971	Ariel Dam, US	daily rain	41.1 mm (1.6 in)	11.9 mm (0.5 in)	24 years	24 of 100 (Routine)
9 April 1971	Ariel Dam, US	daily rain	36.1 mm (1.4 in)	19.8 mm (0.8 in)	16 years	35 of 100 (Notable)
12 March 1971	Ariel Dam, US	daily rain	44.5 mm (1.8 in)	15.8 mm (0.6 in)	24 years	27 of 100 (Routine)
3 March 1971	Ariel Dam, US	daily rain	23.9 mm (0.9 in)	1.0 mm (0.04 in)	20 years	11 of 100 (Routine)
28 February 1971	Ariel Dam, US	daily rain	22.4 mm (0.9 in)	0.6 mm (0.02 in)	31 years	13 of 100 (Routine)
26 January 1971	Ariel Dam, US	daily rain	45.2 mm (1.8 in)	14.2 mm (0.6 in)	39 years	26 of 100 (Routine)
25 January 1971	Ariel Dam, US	daily rain	63.5 mm (2.5 in)	5.6 mm (0.22 in)	7 years	10 of 100 (Routine)
23 January 1971	Ariel Dam, US	daily rain	49.5 mm (1.9 in)	3.8 mm (0.15 in)	17 years	12 of 100 (Routine)
19 January 1971	Ariel Dam, US	daily rain	42.7 mm (1.7 in)	0.5 mm (0.02 in)	36 years	15 of 100 (Routine)
15 January 1971	Ariel Dam, US	daily rain (Tie)	41.1 mm (1.6 in)	tie	15 years	2 of 100 (Routine)
9 January 1971	Ariel Dam, US	daily rain	66.0 mm (2.6 in)	16.7 mm (0.7 in)	12 years	20 of 100 (Routine)
31 December 1970	Ariel Dam, US	daily rain	37.3 mm (1.5 in)	3.5 mm (0.14 in)	16 years	10 of 100 (Routine)
16 December 1970	Ariel Dam, US	daily rain	41.9 mm (1.6 in)	1.8 mm (0.07 in)	13 years	9 of 100 (Routine)
6 September 1970	Ariel Dam, US	daily rain (Tie)	19.1 mm (0.8 in)	tie	32 years	3 of 100 (Routine)
3 September 1970	Ariel Dam, US	daily rain	21.8 mm (0.9 in)	13.9 mm (0.5 in)	5 years	18 of 100 (Routine)
25 July 1970	Ariel Dam, US	daily rain	5.1 mm (0.20 in)	1.8 mm (0.07 in)	7 years	8 of 100 (Routine)

Extremes by Year

1930 to 1971

Yearly extremes at Ariel Dam: the record and the median year
Measure	Record	Year of the record	Median year	Years with a value
Hottest day (TXx)	37.8 C (100.0 F)	1930	31.7 C (89.0 F)	8
Coldest night (TNn)	-11.1 C (12.0 F)	1937	-3.6 C (25.5 F)	8
Wettest day (Rx1day)	111.8 mm (4.4 in)	1962	61.0 mm (2.4 in)	41
Wettest five days (Rx5day)	269.1 mm (10.6 in)	1933	146.0 mm (5.7 in)	41
Longest dry spell (CDD)	70 days	1967	29 days	41

Hottest day (TXx)

The hottest day of the year at Ariel Dam, 1930 to 1971. The record is 37.8 C (100.0 F) in 1930, marked on the chart; the median year is 31.7 C (89.0 F).

Hottest day (TXx) at Ariel Dam by year
Year	Hottest day (TXx)
1930	37.8 C (100.0 F)
1932	n/a
1933	n/a
1934	n/a
1935	13.3 C (55.9 F)
1936	30.0 C (86.0 F)
1937	5.6 C (42.1 F)
1938	35.6 C (96.1 F)
1939	n/a
1940	n/a
1941	n/a
1942	n/a
1943	n/a
1944	n/a
1945	n/a
1946	n/a
1947	n/a
1948	n/a
1949	n/a
1950	n/a
1951	n/a
1952	n/a
1953	n/a
1954	n/a
1955	n/a
1956	n/a
1957	n/a
1958	n/a
1959	n/a
1960	n/a
1961	n/a
1962	n/a
1963	n/a
1964	n/a
1965	33.3 C (91.9 F)
1966	33.3 C (91.9 F)
1967	n/a
1968	n/a
1969	n/a
1970	n/a
1971	27.8 C (82.0 F)

Coldest night (TNn)

The coldest night of the year at Ariel Dam, 1930 to 1971. The record is -11.1 C (12.0 F) in 1937, marked on the chart; the median year is -3.6 C (25.5 F).

Coldest night (TNn) at Ariel Dam by year
Year	Coldest night (TNn)
1930	0.0 C (32.0 F)
1932	n/a
1933	n/a
1934	n/a
1935	-4.4 C (24.1 F)
1936	-3.3 C (26.1 F)
1937	-11.1 C (12.0 F)
1938	-4.4 C (24.1 F)
1939	n/a
1940	n/a
1941	n/a
1942	n/a
1943	n/a
1944	n/a
1945	n/a
1946	n/a
1947	n/a
1948	n/a
1949	n/a
1950	n/a
1951	n/a
1952	n/a
1953	n/a
1954	n/a
1955	n/a
1956	n/a
1957	n/a
1958	n/a
1959	n/a
1960	n/a
1961	n/a
1962	n/a
1963	n/a
1964	n/a
1965	-3.9 C (25.0 F)
1966	2.8 C (37.0 F)
1967	n/a
1968	n/a
1969	n/a
1970	n/a
1971	-1.1 C (30.0 F)

Wettest day (Rx1day)

The wettest day of the year at Ariel Dam, 1930 to 1971. The record is 111.8 mm (4.4 in) in 1962, marked on the chart; the median year is 61.0 mm (2.4 in).

Wettest day (Rx1day) at Ariel Dam by year
Year	Wettest day (Rx1day)
1930	34.3 mm (1.4 in)
1932	54.4 mm (2.1 in)
1933	88.9 mm (3.5 in)
1934	68.8 mm (2.7 in)
1935	42.2 mm (1.7 in)
1936	85.9 mm (3.4 in)
1937	53.8 mm (2.1 in)
1938	52.3 mm (2.1 in)
1939	46.5 mm (1.8 in)
1940	58.9 mm (2.3 in)
1941	64.0 mm (2.5 in)
1942	50.3 mm (2.0 in)
1943	77.7 mm (3.1 in)
1944	33.5 mm (1.3 in)
1945	66.8 mm (2.6 in)
1946	81.5 mm (3.2 in)
1947	50.3 mm (2.0 in)
1948	61.0 mm (2.4 in)
1949	99.1 mm (3.9 in)
1950	78.7 mm (3.1 in)
1951	51.3 mm (2.0 in)
1952	49.5 mm (1.9 in)
1953	52.1 mm (2.1 in)
1954	83.6 mm (3.3 in)
1955	58.9 mm (2.3 in)
1956	75.7 mm (3.0 in)
1957	49.0 mm (1.9 in)
1958	50.8 mm (2.0 in)
1959	65.5 mm (2.6 in)
1960	62.0 mm (2.4 in)
1961	102.1 mm (4.0 in)
1962	111.8 mm (4.4 in)
1963	58.7 mm (2.3 in)
1964	61.0 mm (2.4 in)
1965	74.9 mm (2.9 in)
1966	76.2 mm (3.0 in)
1967	66.3 mm (2.6 in)
1968	54.9 mm (2.2 in)
1969	47.2 mm (1.9 in)
1970	61.5 mm (2.4 in)
1971	66.0 mm (2.6 in)

Wettest five days (Rx5day)

The wettest five days of the year at Ariel Dam, 1930 to 1971. The record is 269.1 mm (10.6 in) in 1933, marked on the chart; the median year is 146.0 mm (5.7 in).

Wettest five days (Rx5day) at Ariel Dam by year
Year	Wettest five days (Rx5day)
1930	105.7 mm (4.2 in)
1932	149.6 mm (5.9 in)
1933	269.1 mm (10.6 in)
1934	181.5 mm (7.1 in)
1935	91.2 mm (3.6 in)
1936	139.7 mm (5.5 in)
1937	184.7 mm (7.3 in)
1938	107.2 mm (4.2 in)
1939	135.1 mm (5.3 in)
1940	151.7 mm (6.0 in)
1941	181.6 mm (7.1 in)
1942	129.4 mm (5.1 in)
1943	140.5 mm (5.5 in)
1944	84.6 mm (3.3 in)
1945	119.1 mm (4.7 in)
1946	265.4 mm (10.4 in)
1947	138.1 mm (5.4 in)
1948	131.8 mm (5.2 in)
1949	155.4 mm (6.1 in)
1950	151.6 mm (6.0 in)
1951	132.9 mm (5.2 in)
1952	118.1 mm (4.6 in)
1953	135.6 mm (5.3 in)
1954	143.0 mm (5.6 in)
1955	166.4 mm (6.6 in)
1956	149.7 mm (5.9 in)
1957	146.0 mm (5.7 in)
1958	161.1 mm (6.3 in)
1959	168.3 mm (6.6 in)
1960	191.1 mm (7.5 in)
1961	148.4 mm (5.8 in)
1962	167.6 mm (6.6 in)
1963	126.5 mm (5.0 in)
1964	159.3 mm (6.3 in)
1965	220.6 mm (8.7 in)
1966	146.0 mm (5.7 in)
1967	140.3 mm (5.5 in)
1968	146.3 mm (5.8 in)
1969	130.3 mm (5.1 in)
1970	138.7 mm (5.5 in)
1971	188.9 mm (7.4 in)

Longest dry spell (CDD)

The longest dry spell of the year at Ariel Dam, 1930 to 1971. The record is 70 days in 1967, marked on the chart; the median year is 29 days.

Longest dry spell (CDD) at Ariel Dam by year
Year	Longest dry spell (CDD)
1930	2 days
1932	30 days
1933	12 days
1934	20 days
1935	19 days
1936	43 days
1937	45 days
1938	20 days
1939	35 days
1940	41 days
1941	38 days
1942	29 days
1943	26 days
1944	24 days
1945	42 days
1946	15 days
1947	25 days
1948	16 days
1949	20 days
1950	31 days
1951	52 days
1952	38 days
1953	30 days
1954	29 days
1955	44 days
1956	25 days
1957	46 days
1958	32 days
1959	29 days
1960	55 days
1961	39 days
1962	27 days
1963	17 days
1964	13 days
1965	29 days
1966	40 days
1967	70 days
1968	24 days
1969	28 days
1970	37 days
1971	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.

Rainfall Return Levels

32 years, 1932 to 1970

A day with at least 61.7 mm (2.4 in) of rain is expected about once in 2 years. A day with at least 127.5 mm (5.0 in) of rain is expected about once in 100 years.

Rainfall return levels at Ariel Dam: the daily rain expected about once in a given number of years
Expected about once in	A day with at least	Note
2 years	61.7 mm (2.4 in)
5 years	77.6 mm (3.1 in)
10 years	88.8 mm (3.5 in)
25 years	103.7 mm (4.1 in)
50 years	115.4 mm (4.5 in)	Longer than the 32 years of record
100 years	127.5 mm (5.0 in)	Longer than the 32 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, 32 years of values from 1932 to 1970.

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: 111.8 mm (4.4 in) in 1962; 102.1 mm (4.0 in) in 1961; 99.1 mm (3.9 in) in 1949.

Download the Data

Data for Ariel Dam standing records by year: CSV or JSON. Field meanings are on the data page.
Data for Ariel Dam 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).