Record envelope, standing records and threshold days for Washington Wwtp 4W (USC00319100), North Carolina, United States, with 134 years of record.
Key Facts for Washington Wwtp 4W
Washington Wwtp 4W (USC00319100) is a weather station in North Carolina, United States at 35.55 latitude and -77.07 longitude, 3 m (10 ft) above sea level.
The station reports from 1893 to 2026, 134 years of record.
1,464 records set at Washington Wwtp 4W still stand.
Records are tracked for prcp, snow, snwd: an element needs 30 years of data to be eligible.
Washington Wwtp 4W set a daily record precipitation of 66.8 mm (2.6 in) on 20 July 2026.
About the Station
Location: North Carolina, United States, 35.55 latitude, -77.07 longitude.
Elevation: 3 m (10 ft).
Period of record: 1893 to 2026, 134 years.
Eligible elements: prcp, snow, snwd.
Daily Record Envelope and 2026
25 days at or beyond a record
Record highRecord low2026 daily maximum2026 daily minimum
The band shows the record high and record low for each calendar day at Washington Wwtp 4W. The lines show the 2026 daily maximum and minimum. 25 days in 2026 matched or passed a record. Temperatures are in degrees Celsius.
Daily record high and record low at Washington Wwtp 4W, with 2026 drawn through them
Month
Highest record high
Lowest record low
2026 highest maximum
2026 lowest minimum
Jan
27.2 C (81.0 F)
-18.3 C (-0.9 F)
23.9 C (75.0 F)
-7.8 C (18.0 F)
Feb
28.9 C (84.0 F)
-15.6 C (3.9 F)
25.6 C (78.1 F)
-9.4 C (15.1 F)
Mar
35.0 C (95.0 F)
-7.2 C (19.0 F)
30.6 C (87.1 F)
-1.1 C (30.0 F)
Apr
32.8 C (91.0 F)
-1.7 C (28.9 F)
32.8 C (91.0 F)
2.2 C (36.0 F)
May
36.1 C (97.0 F)
2.2 C (36.0 F)
33.3 C (91.9 F)
7.2 C (45.0 F)
Jun
38.3 C (100.9 F)
8.3 C (46.9 F)
38.3 C (100.9 F)
10.6 C (51.1 F)
Jul
40.6 C (105.1 F)
13.9 C (57.0 F)
36.7 C (98.1 F)
19.4 C (66.9 F)
Aug
41.7 C (107.1 F)
10.6 C (51.1 F)
36.7 C (98.1 F)
20.6 C (69.1 F)
Sep
37.2 C (99.0 F)
5.6 C (42.1 F)
35.6 C (96.1 F)
12.8 C (55.0 F)
Oct
33.9 C (93.0 F)
-2.2 C (28.0 F)
31.7 C (89.1 F)
10.6 C (51.1 F)
Nov
29.4 C (84.9 F)
-7.8 C (18.0 F)
n/a
n/a
Dec
30.0 C (86.0 F)
-10.6 C (12.9 F)
n/a
n/a
Which Years Hold Standing Records
1,464 standing records
Year with most
1,464 records at Washington Wwtp 4W still stand. 1903 holds the most, with 70.
Standing records at Washington Wwtp 4W by the year they were set
Year set
Standing records
1893
43
1894
33
1900
63
1901
43
1902
63
1903
70
1904
65
1905
56
1906
54
1907
48
1968
3
2004
10
2005
43
2006
39
2007
42
2008
48
2009
45
2010
53
2011
45
2012
31
2013
43
2014
45
2015
52
2016
31
2017
52
2018
50
2019
39
2020
40
2021
31
2022
42
2023
45
2024
30
2025
28
2026
39
All-Time Record Progression
4 new records
4 all-time records were set at Washington Wwtp 4W between 2 March 1980 and 27 August 2011. Each dot is a new record.
When Washington Wwtp 4W set new all-time records
Date
Kind
Detail
1980-03-02
Record daily snowfall
Record daily snowfall 38.4 cm (15.1 in)
1980-03-03
Record snow depth
Record snow depth 40.6 cm (16.0 in)
2010-09-30
Record daily precipitation
Record daily precipitation 204.7 mm (8.1 in)
2011-08-27
Record daily precipitation
Record daily precipitation 289.6 mm (11.4 in)
Wettest Day of Each Month
Aug: 289.6 mm (11.4 in)
The wettest day on record for each calendar month at Washington Wwtp 4W. The most was 289.6 mm (11.4 in) on 27 August 2011.
Record daily precipitation for each month at Washington Wwtp 4W
Month
Record daily precipitation (mm)
Date
Jan
114.3 mm (4.5 in)
29 January 2014
Feb
110.2 mm (4.3 in)
27 February 1906
Mar
113.5 mm (4.5 in)
30 March 1991
Apr
82.8 mm (3.3 in)
16 April 2007
May
114.3 mm (4.5 in)
16 May 2014
Jun
169.4 mm (6.7 in)
30 June 1962
Jul
149.4 mm (5.9 in)
24 July 1985
Aug
289.6 mm (11.4 in)
27 August 2011
Sep
204.7 mm (8.1 in)
30 September 2010
Oct
203.2 mm (8.0 in)
8 October 2016
Nov
133.9 mm (5.3 in)
6 November 1977
Dec
52.6 mm (2.1 in)
17 December 2023
Period of Record Coverage
1893 to 2026
Complete yearUnder 90 percent of days
34 years of record at Washington Wwtp 4W, 1893 to 2026. 9 years have data for under 90 percent of days and are left out of rankings: 1893, 1894, 1900, 1901, 1902, 1907, 1968, 2004 and others.
Cooler than the station meanWarmer than the station mean
One stripe for each of 23 complete years at Washington Wwtp 4W, 1903 to 2025. Blue stripes are years cooler than the station's own mean of 17.0 C (62.5 F); red stripes are warmer. The coolest year was 1904, at 15.5 C (59.9 F), and the warmest was 2024, at 18.1 C (64.6 F). The strongest colour marks a difference of 1.5 C (2.7 F).
Annual mean temperature at Washington Wwtp 4W as warming stripes, 1903 to 2025
Year
Annual mean temperature
Difference from the station mean
1903
17.1 C
+0.16 C
1904
15.5 C
-1.45 C
1905
16.3 C
-0.63 C
1906
17.2 C
+0.27 C
2005
16.5 C
-0.44 C
2006
16.8 C
-0.19 C
2007
17.1 C
+0.11 C
2008
17.4 C
+0.38 C
2009
16.9 C
-0.05 C
2010
16.8 C
-0.15 C
2011
17.8 C
+0.85 C
2012
17.7 C
+0.74 C
2013
16.7 C
-0.31 C
2015
16.9 C
-0.10 C
2016
16.6 C
-0.34 C
2017
16.7 C
-0.26 C
2018
15.8 C
-1.16 C
2019
15.6 C
-1.39 C
2021
17.7 C
+0.68 C
2022
17.7 C
+0.70 C
2023
18.0 C
+1.00 C
2024
18.1 C
+1.13 C
2025
17.4 C
+0.40 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
1893 to 2026
Yearly extremes at Washington Wwtp 4W: the record and the median year
Measure
Record
Year of the record
Median year
Years with a value
Hottest day (TXx)
41.7 C (107.1 F)
1900
36.7 C (98.1 F)
34
Coldest night (TNn)
-18.3 C (-0.9 F)
2018
-8.9 C (16.0 F)
34
Wettest day (Rx1day)
289.6 mm (11.4 in)
2011
79.5 mm (3.1 in)
98
Wettest five days (Rx5day)
444.0 mm (17.5 in)
2010
126.0 mm (5.0 in)
97
Longest dry spell (CDD)
47 days
2001
19 days
98
Hottest day (TXx)
The hottest day of the year at Washington Wwtp 4W, 1893 to 2026. The record is 41.7 C (107.1 F) in 1900, marked on the chart; the median year is 36.7 C (98.1 F).
Hottest day (TXx) at Washington Wwtp 4W by year
Year
Hottest day (TXx)
1893
38.3 C (100.9 F)
1894
35.0 C (95.0 F)
1900
41.7 C (107.1 F)
1901
40.6 C (105.1 F)
1902
40.6 C (105.1 F)
1903
38.3 C (100.9 F)
1904
37.2 C (99.0 F)
1905
36.7 C (98.1 F)
1906
36.7 C (98.1 F)
1907
35.0 C (95.0 F)
1921
n/a
1922
n/a
1923
n/a
1924
n/a
1937
n/a
1938
n/a
1939
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
n/a
1966
n/a
1967
n/a
1968
36.7 C (98.1 F)
1969
n/a
1970
n/a
1971
n/a
1972
n/a
1973
n/a
1974
n/a
1975
n/a
1976
n/a
1977
n/a
1978
n/a
1979
n/a
1980
n/a
1981
n/a
1982
n/a
1983
n/a
1984
n/a
1985
n/a
1986
n/a
1987
n/a
1988
n/a
1989
n/a
1990
n/a
1991
n/a
1992
n/a
1993
n/a
1994
n/a
1995
n/a
1996
n/a
1997
n/a
1998
n/a
1999
n/a
2000
n/a
2001
n/a
2002
n/a
2003
n/a
2004
28.9 C (84.0 F)
2005
37.2 C (99.0 F)
2006
36.7 C (98.1 F)
2007
37.8 C (100.0 F)
2008
38.3 C (100.9 F)
2009
36.1 C (97.0 F)
2010
38.3 C (100.9 F)
2011
39.4 C (102.9 F)
2012
37.2 C (99.0 F)
2013
36.1 C (97.0 F)
2014
35.0 C (95.0 F)
2015
37.2 C (99.0 F)
2016
35.0 C (95.0 F)
2017
33.9 C (93.0 F)
2018
34.4 C (93.9 F)
2019
34.4 C (93.9 F)
2020
36.1 C (97.0 F)
2021
34.4 C (93.9 F)
2022
36.7 C (98.1 F)
2023
37.2 C (99.0 F)
2024
36.7 C (98.1 F)
2025
37.2 C (99.0 F)
2026
38.3 C (100.9 F)
Coldest night (TNn)
The coldest night of the year at Washington Wwtp 4W, 1893 to 2026. The record is -18.3 C (-0.9 F) in 2018, marked on the chart; the median year is -8.9 C (16.0 F).
Coldest night (TNn) at Washington Wwtp 4W by year
Year
Coldest night (TNn)
1893
-6.1 C (21.0 F)
1894
-5.0 C (23.0 F)
1900
-15.6 C (3.9 F)
1901
-10.6 C (12.9 F)
1902
-7.8 C (18.0 F)
1903
-8.3 C (17.1 F)
1904
-12.8 C (9.0 F)
1905
-11.1 C (12.0 F)
1906
-8.9 C (16.0 F)
1907
-8.9 C (16.0 F)
1921
n/a
1922
n/a
1923
n/a
1924
n/a
1937
n/a
1938
n/a
1939
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
n/a
1966
n/a
1967
n/a
1968
11.7 C (53.1 F)
1969
n/a
1970
n/a
1971
n/a
1972
n/a
1973
n/a
1974
n/a
1975
n/a
1976
n/a
1977
n/a
1978
n/a
1979
n/a
1980
n/a
1981
n/a
1982
n/a
1983
n/a
1984
n/a
1985
n/a
1986
n/a
1987
n/a
1988
n/a
1989
n/a
1990
n/a
1991
n/a
1992
n/a
1993
n/a
1994
n/a
1995
n/a
1996
n/a
1997
n/a
1998
n/a
1999
n/a
2000
n/a
2001
n/a
2002
n/a
2003
n/a
2004
-10.0 C (14.0 F)
2005
-9.4 C (15.1 F)
2006
-6.7 C (19.9 F)
2007
-8.3 C (17.1 F)
2008
-7.2 C (19.0 F)
2009
-8.9 C (16.0 F)
2010
-8.9 C (16.0 F)
2011
-7.8 C (18.0 F)
2012
-5.6 C (21.9 F)
2013
-6.7 C (19.9 F)
2014
-10.6 C (12.9 F)
2015
-12.2 C (10.0 F)
2016
-8.9 C (16.0 F)
2017
-11.1 C (12.0 F)
2018
-18.3 C (-0.9 F)
2019
-8.9 C (16.0 F)
2020
-7.8 C (18.0 F)
2021
-5.0 C (23.0 F)
2022
-8.3 C (17.1 F)
2023
-4.4 C (24.1 F)
2024
-6.7 C (19.9 F)
2025
-10.0 C (14.0 F)
2026
-9.4 C (15.1 F)
Wettest day (Rx1day)
The wettest day of the year at Washington Wwtp 4W, 1893 to 2026. The record is 289.6 mm (11.4 in) in 2011, marked on the chart; the median year is 79.5 mm (3.1 in).
Wettest day (Rx1day) at Washington Wwtp 4W by year
Year
Wettest day (Rx1day)
1893
54.9 mm (2.2 in)
1894
73.9 mm (2.9 in)
1900
79.0 mm (3.1 in)
1901
71.1 mm (2.8 in)
1902
50.8 mm (2.0 in)
1903
93.0 mm (3.7 in)
1904
57.4 mm (2.3 in)
1905
55.1 mm (2.2 in)
1906
110.2 mm (4.3 in)
1907
78.0 mm (3.1 in)
1921
69.9 mm (2.8 in)
1922
50.0 mm (2.0 in)
1923
61.0 mm (2.4 in)
1924
0.0 mm (0.00 in)
1937
25.4 mm (1.0 in)
1938
73.7 mm (2.9 in)
1939
52.8 mm (2.1 in)
1946
92.5 mm (3.6 in)
1947
192.5 mm (7.6 in)
1948
78.7 mm (3.1 in)
1949
128.3 mm (5.1 in)
1950
57.9 mm (2.3 in)
1951
134.1 mm (5.3 in)
1952
74.4 mm (2.9 in)
1953
95.3 mm (3.8 in)
1954
60.7 mm (2.4 in)
1955
179.8 mm (7.1 in)
1956
87.4 mm (3.4 in)
1957
59.9 mm (2.4 in)
1958
49.5 mm (1.9 in)
1959
62.5 mm (2.5 in)
1960
129.5 mm (5.1 in)
1961
66.0 mm (2.6 in)
1962
169.4 mm (6.7 in)
1963
102.4 mm (4.0 in)
1964
141.0 mm (5.6 in)
1965
122.2 mm (4.8 in)
1966
63.5 mm (2.5 in)
1967
77.5 mm (3.1 in)
1968
73.9 mm (2.9 in)
1969
117.1 mm (4.6 in)
1970
57.2 mm (2.3 in)
1971
128.3 mm (5.1 in)
1972
91.4 mm (3.6 in)
1973
91.4 mm (3.6 in)
1974
56.6 mm (2.2 in)
1975
84.6 mm (3.3 in)
1976
54.9 mm (2.2 in)
1977
133.9 mm (5.3 in)
1978
62.5 mm (2.5 in)
1979
58.9 mm (2.3 in)
1980
77.0 mm (3.0 in)
1981
63.0 mm (2.5 in)
1982
100.3 mm (3.9 in)
1983
70.6 mm (2.8 in)
1984
75.4 mm (3.0 in)
1985
149.4 mm (5.9 in)
1986
54.6 mm (2.1 in)
1987
80.0 mm (3.1 in)
1988
52.8 mm (2.1 in)
1989
44.2 mm (1.7 in)
1990
70.6 mm (2.8 in)
1991
113.5 mm (4.5 in)
1992
63.8 mm (2.5 in)
1993
50.8 mm (2.0 in)
1994
102.4 mm (4.0 in)
1995
114.3 mm (4.5 in)
1996
125.7 mm (4.9 in)
1997
47.0 mm (1.9 in)
1998
139.7 mm (5.5 in)
1999
161.5 mm (6.4 in)
2000
92.7 mm (3.6 in)
2001
78.7 mm (3.1 in)
2002
53.8 mm (2.1 in)
2003
124.5 mm (4.9 in)
2004
51.3 mm (2.0 in)
2005
131.8 mm (5.2 in)
2006
165.6 mm (6.5 in)
2007
82.8 mm (3.3 in)
2008
82.8 mm (3.3 in)
2009
107.7 mm (4.2 in)
2010
204.7 mm (8.1 in)
2011
289.6 mm (11.4 in)
2012
74.2 mm (2.9 in)
2013
88.9 mm (3.5 in)
2014
115.1 mm (4.5 in)
2015
140.5 mm (5.5 in)
2016
203.2 mm (8.0 in)
2017
88.9 mm (3.5 in)
2018
85.3 mm (3.4 in)
2019
75.2 mm (3.0 in)
2020
125.5 mm (4.9 in)
2021
125.2 mm (4.9 in)
2022
117.1 mm (4.6 in)
2023
87.4 mm (3.4 in)
2024
74.9 mm (2.9 in)
2025
96.0 mm (3.8 in)
2026
66.8 mm (2.6 in)
Wettest five days (Rx5day)
The wettest five days of the year at Washington Wwtp 4W, 1893 to 2026. The record is 444.0 mm (17.5 in) in 2010, marked on the chart; the median year is 126.0 mm (5.0 in).
Wettest five days (Rx5day) at Washington Wwtp 4W by year
Year
Wettest five days (Rx5day)
1893
105.6 mm (4.2 in)
1894
95.3 mm (3.8 in)
1900
79.0 mm (3.1 in)
1901
106.5 mm (4.2 in)
1902
90.2 mm (3.6 in)
1903
118.8 mm (4.7 in)
1904
136.7 mm (5.4 in)
1905
84.4 mm (3.3 in)
1906
127.7 mm (5.0 in)
1907
133.6 mm (5.3 in)
1921
83.4 mm (3.3 in)
1922
103.5 mm (4.1 in)
1923
127.3 mm (5.0 in)
1924
n/a
1937
35.6 mm (1.4 in)
1938
159.0 mm (6.3 in)
1939
101.1 mm (4.0 in)
1946
126.0 mm (5.0 in)
1947
251.1 mm (9.9 in)
1948
90.4 mm (3.6 in)
1949
139.0 mm (5.5 in)
1950
205.7 mm (8.1 in)
1951
202.1 mm (8.0 in)
1952
111.2 mm (4.4 in)
1953
101.0 mm (4.0 in)
1954
65.8 mm (2.6 in)
1955
209.7 mm (8.3 in)
1956
134.5 mm (5.3 in)
1957
119.6 mm (4.7 in)
1958
93.2 mm (3.7 in)
1959
156.9 mm (6.2 in)
1960
150.1 mm (5.9 in)
1961
112.2 mm (4.4 in)
1962
276.9 mm (10.9 in)
1963
102.4 mm (4.0 in)
1964
157.3 mm (6.2 in)
1965
141.0 mm (5.6 in)
1966
90.2 mm (3.6 in)
1967
156.4 mm (6.2 in)
1968
104.4 mm (4.1 in)
1969
138.5 mm (5.5 in)
1970
85.4 mm (3.4 in)
1971
246.6 mm (9.7 in)
1972
101.0 mm (4.0 in)
1973
106.2 mm (4.2 in)
1974
91.6 mm (3.6 in)
1975
141.8 mm (5.6 in)
1976
60.6 mm (2.4 in)
1977
143.0 mm (5.6 in)
1978
81.4 mm (3.2 in)
1979
77.2 mm (3.0 in)
1980
89.7 mm (3.5 in)
1981
110.3 mm (4.3 in)
1982
106.7 mm (4.2 in)
1983
107.9 mm (4.2 in)
1984
154.8 mm (6.1 in)
1985
197.2 mm (7.8 in)
1986
104.7 mm (4.1 in)
1987
109.5 mm (4.3 in)
1988
64.1 mm (2.5 in)
1989
88.9 mm (3.5 in)
1990
108.2 mm (4.3 in)
1991
130.4 mm (5.1 in)
1992
203.2 mm (8.0 in)
1993
60.4 mm (2.4 in)
1994
107.7 mm (4.2 in)
1995
168.9 mm (6.6 in)
1996
164.6 mm (6.5 in)
1997
77.7 mm (3.1 in)
1998
141.7 mm (5.6 in)
1999
393.1 mm (15.5 in)
2000
151.3 mm (6.0 in)
2001
142.1 mm (5.6 in)
2002
70.9 mm (2.8 in)
2003
147.4 mm (5.8 in)
2004
91.4 mm (3.6 in)
2005
280.9 mm (11.1 in)
2006
187.2 mm (7.4 in)
2007
91.2 mm (3.6 in)
2008
87.7 mm (3.5 in)
2009
199.9 mm (7.9 in)
2010
444.0 mm (17.5 in)
2011
407.4 mm (16.0 in)
2012
164.0 mm (6.5 in)
2013
108.5 mm (4.3 in)
2014
163.3 mm (6.4 in)
2015
188.2 mm (7.4 in)
2016
241.9 mm (9.5 in)
2017
104.3 mm (4.1 in)
2018
152.2 mm (6.0 in)
2019
122.9 mm (4.8 in)
2020
137.7 mm (5.4 in)
2021
156.6 mm (6.2 in)
2022
120.7 mm (4.8 in)
2023
128.0 mm (5.0 in)
2024
127.0 mm (5.0 in)
2025
130.3 mm (5.1 in)
2026
145.3 mm (5.7 in)
Longest dry spell (CDD)
The longest dry spell of the year at Washington Wwtp 4W, 1893 to 2026. The record is 47 days in 2001, marked on the chart; the median year is 19 days.
Longest dry spell (CDD) at Washington Wwtp 4W by year
Year
Longest dry spell (CDD)
1893
15 days
1894
11 days
1900
15 days
1901
20 days
1902
12 days
1903
17 days
1904
22 days
1905
19 days
1906
21 days
1907
16 days
1921
13 days
1922
14 days
1923
20 days
1924
2 days
1937
14 days
1938
20 days
1939
18 days
1946
18 days
1947
15 days
1948
15 days
1949
11 days
1950
21 days
1951
14 days
1952
18 days
1953
20 days
1954
24 days
1955
15 days
1956
17 days
1957
19 days
1958
24 days
1959
11 days
1960
16 days
1961
23 days
1962
19 days
1963
19 days
1964
19 days
1965
31 days
1966
24 days
1967
20 days
1968
20 days
1969
18 days
1970
25 days
1971
15 days
1972
21 days
1973
23 days
1974
23 days
1975
14 days
1976
19 days
1977
18 days
1978
21 days
1979
12 days
1980
15 days
1981
21 days
1982
17 days
1983
19 days
1984
27 days
1985
30 days
1986
23 days
1987
26 days
1988
21 days
1989
12 days
1990
21 days
1991
22 days
1992
19 days
1993
17 days
1994
15 days
1995
19 days
1996
20 days
1997
17 days
1998
25 days
1999
22 days
2000
25 days
2001
47 days
2002
16 days
2003
21 days
2004
15 days
2005
16 days
2006
20 days
2007
27 days
2008
27 days
2009
13 days
2010
21 days
2011
21 days
2012
14 days
2013
18 days
2014
21 days
2015
14 days
2016
13 days
2017
15 days
2018
15 days
2019
22 days
2020
13 days
2021
16 days
2022
27 days
2023
22 days
2024
25 days
2025
26 days
2026
19 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 Washington Wwtp 4W falls on 29 March and the median first autumn frost on 13 November, which leaves a median of 232 days between them.
Frost dates and growing season at Washington Wwtp 4W
Measure
Median, all years
Earliest period
Recent period (1903 to 2025)
Recent against earliest
Fitted trend
Last spring frost
29 March
n/a
29 March
n/a
n/a
First autumn frost
13 November
n/a
13 November
n/a
n/a
Growing days
232 days
n/a
232 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.
Rainfall Return Levels
87 years, 1901 to 2025
A day with at least 86.9 mm (3.4 in) of rain is expected about once in 2 years. A day with at least 259.7 mm (10.2 in) of rain is expected about once in 100 years.
Rainfall return levels at Washington Wwtp 4W: the daily rain expected about once in a given number of years
Expected about once in
A day with at least
Note
2 years
86.9 mm (3.4 in)
5 years
123.2 mm (4.9 in)
10 years
150.8 mm (5.9 in)
25 years
190.3 mm (7.5 in)
50 years
223.4 mm (8.8 in)
100 years
259.7 mm (10.2 in)
Longer than the 87 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, 87 years of values from 1901 to 2025.
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: 289.6 mm (11.4 in) in 2011; 204.7 mm (8.1 in) in 2010; 203.2 mm (8.0 in) in 2016.
Download the Data
Data for Washington Wwtp 4W standing records by year: CSV or JSON. Field meanings are on the data page.
Data for Washington Wwtp 4W 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.