Record envelope, standing records and threshold days for Waterville Wwtp (USC00179826), Maine, United States, with 64 years of record.
Key Facts for Waterville Wwtp
Waterville Wwtp (USC00179826) is a weather station in Maine, United States at 44.55 latitude and -69.63 longitude, 27 m (89 ft) above sea level.
The station reports from 1895 to 1958, 64 years of record.
1,464 records set at Waterville Wwtp still stand.
Records are tracked for tmax, tmin, prcp, snow: an element needs 30 years of data to be eligible.
Waterville Wwtp set a daily record low maximum temperature of 13.9 C (57.0 F) on 22 June 1958.
About the Station
Location: Maine, United States, 44.55 latitude, -69.63 longitude.
Elevation: 27 m (89 ft).
Period of record: 1895 to 1958, 64 years.
Eligible elements: tmax, tmin, prcp, snow.
Daily Record Envelope and 2026
0 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 Waterville Wwtp. 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 Waterville Wwtp, with 2026 drawn through them
Month
Highest record high
Lowest record low
2026 highest maximum
2026 lowest minimum
Jan
16.1 C (61.0 F)
-37.8 C (-36.0 F)
n/a
n/a
Feb
15.0 C (59.0 F)
-37.2 C (-35.0 F)
n/a
n/a
Mar
26.7 C (80.1 F)
-28.9 C (-20.0 F)
n/a
n/a
Apr
31.1 C (88.0 F)
-18.3 C (-0.9 F)
n/a
n/a
May
36.7 C (98.1 F)
-5.6 C (21.9 F)
n/a
n/a
Jun
36.7 C (98.1 F)
-3.3 C (26.1 F)
n/a
n/a
Jul
38.3 C (100.9 F)
2.8 C (37.0 F)
n/a
n/a
Aug
37.2 C (99.0 F)
-0.6 C (30.9 F)
n/a
n/a
Sep
35.0 C (95.0 F)
-5.0 C (23.0 F)
n/a
n/a
Oct
32.2 C (90.0 F)
-10.0 C (14.0 F)
n/a
n/a
Nov
22.8 C (73.0 F)
-21.1 C (-6.0 F)
n/a
n/a
Dec
16.7 C (62.1 F)
-39.4 C (-38.9 F)
n/a
n/a
Which Years Hold Standing Records
1,464 standing records
Year with most
1,464 records at Waterville Wwtp still stand. 1904 holds the most, with 44.
Standing records at Waterville Wwtp by the year they were set
Year set
Standing records
1896
28
1897
22
1898
19
1899
29
1900
21
1901
35
1902
34
1903
39
1904
44
1905
21
1906
25
1907
27
1908
27
1909
21
1910
22
1911
40
1912
31
1913
24
1914
24
1915
21
1916
23
1917
30
1918
24
1919
26
1920
33
1921
24
1922
17
1923
25
1924
6
1925
16
1926
24
1927
22
1928
19
1929
30
1930
27
1931
19
1932
12
1933
18
1934
20
1935
15
1936
19
1937
20
1938
25
1939
12
1940
11
1941
17
1942
24
1943
22
1944
22
1945
21
1946
22
1947
22
1948
24
1949
30
1950
25
1951
21
1952
12
1953
30
1954
26
1955
26
1956
23
1957
22
1958
4
All-Time Record Progression
7 new records
7 all-time records were set at Waterville Wwtp between 16 September 1932 and 12 September 1954. Each dot is a new record.
When Waterville Wwtp set new all-time records
Date
Kind
Detail
1932-09-16
Record daily precipitation
Record daily precipitation 137.7 mm (5.4 in)
1933-12-30
Record low maximum temperature
Record low maximum temperature -20.0 C (-4.0 F)
1933-12-30
Record low minimum temperature
Record low minimum temperature -39.4 C (-38.9 F)
1947-01-10
Record low maximum temperature
Record low maximum temperature -23.3 C (-9.9 F)
1949-08-09
Record high minimum temperature
Record high minimum temperature 24.4 C (75.9 F)
1949-08-27
Record high minimum temperature
Record high minimum temperature 25.0 C (77.0 F)
1954-09-12
Record daily precipitation
Record daily precipitation 165.1 mm (6.5 in)
Wettest Day of Each Month
Sep: 165.1 mm (6.5 in)
The wettest day on record for each calendar month at Waterville Wwtp. The most was 165.1 mm (6.5 in) on 12 September 1954.
Record daily precipitation for each month at Waterville Wwtp
Month
Record daily precipitation (mm)
Date
Jan
63.0 mm (2.5 in)
6 January 1909
Feb
52.3 mm (2.1 in)
13 February 1900
Mar
63.5 mm (2.5 in)
2 March 1900
Apr
89.7 mm (3.5 in)
12 April 1940
May
72.4 mm (2.9 in)
18 May 1948
Jun
82.6 mm (3.3 in)
17 June 1917
Jul
124.0 mm (4.9 in)
18 July 1922
Aug
82.6 mm (3.3 in)
4 August 1910
Sep
165.1 mm (6.5 in)
12 September 1954
Oct
101.9 mm (4.0 in)
1 October 1946
Nov
96.5 mm (3.8 in)
1 November 1955
Dec
84.6 mm (3.3 in)
15 December 1901
Period of Record Coverage
1896 to 1958
Complete yearUnder 90 percent of days
63 years of record at Waterville Wwtp, 1896 to 1958. 9 years have data for under 90 percent of days and are left out of rankings: 1896, 1899, 1900, 1908, 1932, 1939, 1946, 1947 and others.
Cooler than the station meanWarmer than the station mean
One stripe for each of 51 complete years at Waterville Wwtp, 1897 to 1957. Blue stripes are years cooler than the station's own mean of 7.1 C (44.8 F); red stripes are warmer. The coolest year was 1907, at 5.4 C (41.8 F), and the warmest was 1941, at 8.6 C (47.5 F). The strongest colour marks a difference of 1.7 C (3.1 F).
Annual mean temperature at Waterville Wwtp as warming stripes, 1897 to 1957
Year
Annual mean temperature
Difference from the station mean
1897
6.7 C
-0.47 C
1898
7.4 C
+0.27 C
1901
6.8 C
-0.37 C
1902
6.4 C
-0.78 C
1905
5.7 C
-1.39 C
1906
6.3 C
-0.83 C
1907
5.4 C
-1.69 C
1909
6.5 C
-0.68 C
1910
6.6 C
-0.52 C
1911
7.3 C
+0.18 C
1912
6.6 C
-0.54 C
1913
8.2 C
+1.04 C
1914
6.4 C
-0.72 C
1915
8.0 C
+0.88 C
1916
6.9 C
-0.22 C
1918
6.7 C
-0.47 C
1919
7.0 C
-0.16 C
1920
6.8 C
-0.34 C
1921
8.2 C
+1.08 C
1922
7.1 C
-0.07 C
1923
6.6 C
-0.58 C
1924
6.5 C
-0.61 C
1925
6.7 C
-0.48 C
1926
5.5 C
-1.64 C
1927
7.2 C
+0.11 C
1929
7.5 C
+0.35 C
1930
8.0 C
+0.84 C
1931
8.6 C
+1.44 C
1932
8.0 C
+0.84 C
1933
7.3 C
+0.18 C
1934
6.7 C
-0.41 C
1935
6.8 C
-0.29 C
1936
7.2 C
+0.05 C
1937
8.4 C
+1.24 C
1938
7.9 C
+0.78 C
1940
7.1 C
-0.02 C
1941
8.6 C
+1.50 C
1942
8.3 C
+1.14 C
1943
6.6 C
-0.56 C
1944
7.3 C
+0.14 C
1945
7.2 C
+0.07 C
1948
6.7 C
-0.42 C
1949
8.3 C
+1.12 C
1950
6.9 C
-0.24 C
1951
7.2 C
+0.07 C
1952
7.8 C
+0.64 C
1953
8.4 C
+1.25 C
1954
6.6 C
-0.52 C
1955
7.0 C
-0.17 C
1956
6.5 C
-0.68 C
1957
7.6 C
+0.48 C
The annual mean temperature here has risen by 0.16 C (0.04 to 0.28) per decade over 1897 to 1957. In Fahrenheit: 0.3 F (0.1 to 0.5) per decade. The slope is a straight line fitted to 51 complete years; the brackets give its 95 percent interval.
Fitted temperature trends per decade at Waterville Wwtp
Measure
Per decade (C)
Per decade (F)
Period
Complete years
Reading
Annual mean temperature
0.16 C (0.04 to 0.28) per decade
0.3 F (0.1 to 0.5) per decade
1897 to 1957
51
Rise
Mean daily maximum
0.1 C (-0.1 to 0.2) per decade
0.1 F (-0.1 to 0.3) per decade
1897 to 1957
51
Not clearly different from zero
Mean daily minimum
0.3 C (0.1 to 0.4) per decade
0.5 F (0.2 to 0.7) per decade
1897 to 1957
51
Rise
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
1895 to 1958
Yearly extremes at Waterville Wwtp: the record and the median year
Measure
Record
Year of the record
Median year
Years with a value
Hottest day (TXx)
38.3 C (100.9 F)
1911
34.4 C (93.9 F)
63
Coldest night (TNn)
-39.4 C (-38.9 F)
1933
-29.4 C (-20.9 F)
63
Wettest day (Rx1day)
165.1 mm (6.5 in)
1954
57.3 mm (2.3 in)
64
Wettest five days (Rx5day)
205.2 mm (8.1 in)
1954
85.8 mm (3.4 in)
64
Longest dry spell (CDD)
39 days
1905
18 days
64
Hottest day (TXx)
The hottest day of the year at Waterville Wwtp, 1895 to 1958. The record is 38.3 C (100.9 F) in 1911, marked on the chart; the median year is 34.4 C (93.9 F).
Hottest day (TXx) at Waterville Wwtp by year
Year
Hottest day (TXx)
1895
n/a
1896
35.0 C (95.0 F)
1897
35.6 C (96.1 F)
1898
35.6 C (96.1 F)
1899
34.4 C (93.9 F)
1900
35.0 C (95.0 F)
1901
37.2 C (99.0 F)
1902
32.2 C (90.0 F)
1903
33.3 C (91.9 F)
1904
32.2 C (90.0 F)
1905
32.2 C (90.0 F)
1906
33.9 C (93.0 F)
1907
33.9 C (93.0 F)
1908
36.1 C (97.0 F)
1909
35.6 C (96.1 F)
1910
32.2 C (90.0 F)
1911
38.3 C (100.9 F)
1912
36.1 C (97.0 F)
1913
35.6 C (96.1 F)
1914
33.3 C (91.9 F)
1915
32.2 C (90.0 F)
1916
36.1 C (97.0 F)
1917
36.1 C (97.0 F)
1918
34.4 C (93.9 F)
1919
36.7 C (98.1 F)
1920
33.9 C (93.0 F)
1921
35.0 C (95.0 F)
1922
32.2 C (90.0 F)
1923
34.4 C (93.9 F)
1924
33.3 C (91.9 F)
1925
33.3 C (91.9 F)
1926
36.1 C (97.0 F)
1927
32.2 C (90.0 F)
1928
35.0 C (95.0 F)
1929
33.9 C (93.0 F)
1930
33.3 C (91.9 F)
1931
33.9 C (93.0 F)
1932
33.3 C (91.9 F)
1933
33.9 C (93.0 F)
1934
33.3 C (91.9 F)
1935
35.6 C (96.1 F)
1936
33.3 C (91.9 F)
1937
35.6 C (96.1 F)
1938
33.9 C (93.0 F)
1939
34.4 C (93.9 F)
1940
33.3 C (91.9 F)
1941
36.1 C (97.0 F)
1942
34.4 C (93.9 F)
1943
35.0 C (95.0 F)
1944
36.7 C (98.1 F)
1945
34.4 C (93.9 F)
1946
36.7 C (98.1 F)
1947
36.1 C (97.0 F)
1948
36.1 C (97.0 F)
1949
36.1 C (97.0 F)
1950
33.3 C (91.9 F)
1951
32.2 C (90.0 F)
1952
36.1 C (97.0 F)
1953
34.4 C (93.9 F)
1954
33.3 C (91.9 F)
1955
37.2 C (99.0 F)
1956
35.0 C (95.0 F)
1957
33.3 C (91.9 F)
1958
28.9 C (84.0 F)
Coldest night (TNn)
The coldest night of the year at Waterville Wwtp, 1895 to 1958. The record is -39.4 C (-38.9 F) in 1933, marked on the chart; the median year is -29.4 C (-20.9 F).
Coldest night (TNn) at Waterville Wwtp by year
Year
Coldest night (TNn)
1895
n/a
1896
-22.2 C (-8.0 F)
1897
-26.7 C (-16.1 F)
1898
-34.4 C (-29.9 F)
1899
-33.3 C (-27.9 F)
1900
-31.1 C (-24.0 F)
1901
-31.1 C (-24.0 F)
1902
-28.3 C (-18.9 F)
1903
-31.1 C (-24.0 F)
1904
-30.6 C (-23.1 F)
1905
-34.4 C (-29.9 F)
1906
-28.3 C (-18.9 F)
1907
-37.8 C (-36.0 F)
1908
-27.2 C (-17.0 F)
1909
-29.4 C (-20.9 F)
1910
-27.8 C (-18.0 F)
1911
-27.2 C (-17.0 F)
1912
-35.6 C (-32.1 F)
1913
-24.4 C (-11.9 F)
1914
-31.7 C (-25.1 F)
1915
-28.3 C (-18.9 F)
1916
-26.7 C (-16.1 F)
1917
-31.7 C (-25.1 F)
1918
-32.8 C (-27.0 F)
1919
-29.4 C (-20.9 F)
1920
-34.4 C (-29.9 F)
1921
-24.4 C (-11.9 F)
1922
-33.3 C (-27.9 F)
1923
-32.2 C (-26.0 F)
1924
-32.2 C (-26.0 F)
1925
-35.6 C (-32.1 F)
1926
-28.9 C (-20.0 F)
1927
-28.9 C (-20.0 F)
1928
-29.4 C (-20.9 F)
1929
-30.6 C (-23.1 F)
1930
-29.4 C (-20.9 F)
1931
-30.6 C (-23.1 F)
1932
-26.7 C (-16.1 F)
1933
-39.4 C (-38.9 F)
1934
-37.2 C (-35.0 F)
1935
-35.0 C (-31.0 F)
1936
-27.8 C (-18.0 F)
1937
-22.8 C (-9.0 F)
1938
-28.3 C (-18.9 F)
1939
-31.1 C (-24.0 F)
1940
-30.0 C (-22.0 F)
1941
-22.8 C (-9.0 F)
1942
-29.4 C (-20.9 F)
1943
-32.2 C (-26.0 F)
1944
-27.8 C (-18.0 F)
1945
-30.6 C (-23.1 F)
1946
-27.2 C (-17.0 F)
1947
-28.9 C (-20.0 F)
1948
-31.1 C (-24.0 F)
1949
-26.1 C (-15.0 F)
1950
-26.1 C (-15.0 F)
1951
-30.6 C (-23.1 F)
1952
-23.9 C (-11.0 F)
1953
-19.4 C (-2.9 F)
1954
-27.8 C (-18.0 F)
1955
-30.0 C (-22.0 F)
1956
-28.9 C (-20.0 F)
1957
-31.7 C (-25.1 F)
1958
-28.3 C (-18.9 F)
Wettest day (Rx1day)
The wettest day of the year at Waterville Wwtp, 1895 to 1958. The record is 165.1 mm (6.5 in) in 1954, marked on the chart; the median year is 57.3 mm (2.3 in).
Wettest day (Rx1day) at Waterville Wwtp by year
Year
Wettest day (Rx1day)
1895
47.0 mm (1.9 in)
1896
75.7 mm (3.0 in)
1897
38.1 mm (1.5 in)
1898
38.1 mm (1.5 in)
1899
29.5 mm (1.2 in)
1900
63.5 mm (2.5 in)
1901
84.6 mm (3.3 in)
1902
94.0 mm (3.7 in)
1903
80.3 mm (3.2 in)
1904
66.5 mm (2.6 in)
1905
46.2 mm (1.8 in)
1906
63.0 mm (2.5 in)
1907
47.0 mm (1.9 in)
1908
47.8 mm (1.9 in)
1909
63.0 mm (2.5 in)
1910
82.6 mm (3.3 in)
1911
48.3 mm (1.9 in)
1912
59.7 mm (2.4 in)
1913
64.0 mm (2.5 in)
1914
60.5 mm (2.4 in)
1915
105.4 mm (4.1 in)
1916
83.3 mm (3.3 in)
1917
82.6 mm (3.3 in)
1918
56.1 mm (2.2 in)
1919
46.2 mm (1.8 in)
1920
76.5 mm (3.0 in)
1921
39.1 mm (1.5 in)
1922
124.0 mm (4.9 in)
1923
64.8 mm (2.6 in)
1924
36.6 mm (1.4 in)
1925
68.6 mm (2.7 in)
1926
58.2 mm (2.3 in)
1927
48.8 mm (1.9 in)
1928
63.8 mm (2.5 in)
1929
41.9 mm (1.6 in)
1930
47.8 mm (1.9 in)
1931
45.7 mm (1.8 in)
1932
137.7 mm (5.4 in)
1933
44.5 mm (1.8 in)
1934
134.1 mm (5.3 in)
1935
46.0 mm (1.8 in)
1936
59.9 mm (2.4 in)
1937
55.9 mm (2.2 in)
1938
48.8 mm (1.9 in)
1939
49.0 mm (1.9 in)
1940
89.7 mm (3.5 in)
1941
61.7 mm (2.4 in)
1942
42.2 mm (1.7 in)
1943
47.5 mm (1.9 in)
1944
76.2 mm (3.0 in)
1945
45.7 mm (1.8 in)
1946
101.9 mm (4.0 in)
1947
37.8 mm (1.5 in)
1948
72.4 mm (2.9 in)
1949
32.3 mm (1.3 in)
1950
75.2 mm (3.0 in)
1951
50.3 mm (2.0 in)
1952
50.0 mm (2.0 in)
1953
56.4 mm (2.2 in)
1954
165.1 mm (6.5 in)
1955
96.5 mm (3.8 in)
1956
49.3 mm (1.9 in)
1957
31.8 mm (1.3 in)
1958
47.8 mm (1.9 in)
Wettest five days (Rx5day)
The wettest five days of the year at Waterville Wwtp, 1895 to 1958. The record is 205.2 mm (8.1 in) in 1954, marked on the chart; the median year is 85.8 mm (3.4 in).
Wettest five days (Rx5day) at Waterville Wwtp by year
Year
Wettest five days (Rx5day)
1895
56.1 mm (2.2 in)
1896
101.4 mm (4.0 in)
1897
54.1 mm (2.1 in)
1898
55.6 mm (2.2 in)
1899
77.9 mm (3.1 in)
1900
85.3 mm (3.4 in)
1901
84.6 mm (3.3 in)
1902
94.3 mm (3.7 in)
1903
109.5 mm (4.3 in)
1904
73.9 mm (2.9 in)
1905
60.1 mm (2.4 in)
1906
96.0 mm (3.8 in)
1907
60.2 mm (2.4 in)
1908
96.5 mm (3.8 in)
1909
123.9 mm (4.9 in)
1910
83.9 mm (3.3 in)
1911
68.8 mm (2.7 in)
1912
81.8 mm (3.2 in)
1913
82.9 mm (3.3 in)
1914
71.9 mm (2.8 in)
1915
114.0 mm (4.5 in)
1916
85.6 mm (3.4 in)
1917
91.2 mm (3.6 in)
1918
76.7 mm (3.0 in)
1919
68.6 mm (2.7 in)
1920
113.6 mm (4.5 in)
1921
46.2 mm (1.8 in)
1922
129.1 mm (5.1 in)
1923
99.4 mm (3.9 in)
1924
49.8 mm (2.0 in)
1925
107.7 mm (4.2 in)
1926
85.9 mm (3.4 in)
1927
94.3 mm (3.7 in)
1928
152.3 mm (6.0 in)
1929
58.7 mm (2.3 in)
1930
65.8 mm (2.6 in)
1931
91.8 mm (3.6 in)
1932
139.5 mm (5.5 in)
1933
101.6 mm (4.0 in)
1934
152.4 mm (6.0 in)
1935
73.4 mm (2.9 in)
1936
76.7 mm (3.0 in)
1937
118.4 mm (4.7 in)
1938
95.2 mm (3.7 in)
1939
71.9 mm (2.8 in)
1940
111.0 mm (4.4 in)
1941
86.6 mm (3.4 in)
1942
90.9 mm (3.6 in)
1943
91.2 mm (3.6 in)
1944
87.4 mm (3.4 in)
1945
62.3 mm (2.5 in)
1946
106.5 mm (4.2 in)
1947
67.6 mm (2.7 in)
1948
120.1 mm (4.7 in)
1949
79.0 mm (3.1 in)
1950
104.9 mm (4.1 in)
1951
71.9 mm (2.8 in)
1952
57.9 mm (2.3 in)
1953
98.5 mm (3.9 in)
1954
205.2 mm (8.1 in)
1955
110.0 mm (4.3 in)
1956
62.1 mm (2.4 in)
1957
51.7 mm (2.0 in)
1958
65.3 mm (2.6 in)
Longest dry spell (CDD)
The longest dry spell of the year at Waterville Wwtp, 1895 to 1958. The record is 39 days in 1905, marked on the chart; the median year is 18 days.
Longest dry spell (CDD) at Waterville Wwtp by year
Year
Longest dry spell (CDD)
1895
24 days
1896
13 days
1897
18 days
1898
14 days
1899
22 days
1900
19 days
1901
17 days
1902
13 days
1903
19 days
1904
17 days
1905
39 days
1906
12 days
1907
15 days
1908
24 days
1909
19 days
1910
35 days
1911
21 days
1912
20 days
1913
18 days
1914
23 days
1915
22 days
1916
15 days
1917
18 days
1918
30 days
1919
20 days
1920
18 days
1921
19 days
1922
15 days
1923
17 days
1924
25 days
1925
21 days
1926
11 days
1927
16 days
1928
17 days
1929
15 days
1930
23 days
1931
14 days
1932
16 days
1933
11 days
1934
14 days
1935
18 days
1936
8 days
1937
13 days
1938
28 days
1939
26 days
1940
21 days
1941
19 days
1942
16 days
1943
16 days
1944
15 days
1945
17 days
1946
24 days
1947
14 days
1948
21 days
1949
19 days
1950
24 days
1951
15 days
1952
21 days
1953
14 days
1954
15 days
1955
16 days
1956
15 days
1957
15 days
1958
14 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
51 years with a frost
Across 51 years with a frost, the median last spring frost at Waterville Wwtp falls on 17 May and the median first autumn frost on 25 September, which leaves a median of 132 days between them.
Fitted over all years, the growing season changes by +4.2 days per decade at this station.
Frost dates and growing season at Waterville Wwtp
Measure
Median, all years
Earliest period
Recent period (1924 to 1957)
Recent against earliest
Fitted trend
Last spring frost
17 May
n/a
15 May
n/a
-2.4 days per decade
First autumn frost
25 September
n/a
28 September
n/a
+1.8 days per decade
Growing days
132 days
n/a
137 days
n/a
+4.2 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
57 years, 1896 to 1957
A day with at least 59.0 mm (2.3 in) of rain is expected about once in 2 years. A day with at least 172.7 mm (6.8 in) of rain is expected about once in 100 years.
Rainfall return levels at Waterville Wwtp: the daily rain expected about once in a given number of years
Expected about once in
A day with at least
Note
2 years
59.0 mm (2.3 in)
5 years
82.5 mm (3.2 in)
10 years
100.4 mm (4.0 in)
25 years
126.4 mm (5.0 in)
50 years
148.3 mm (5.8 in)
100 years
172.7 mm (6.8 in)
Longer than the 57 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, 57 years of values from 1896 to 1957.
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: 165.1 mm (6.5 in) in 1954; 137.7 mm (5.4 in) in 1932; 134.1 mm (5.3 in) in 1934.
Station Changes
1 suspected
One change was suspected in the annual mean temperature of Waterville Wwtp, at 1911. Each is measured against neighbouring stations.
Relative to 5 neighbouring stations, the station's annual mean temperature from 1911 ran 0.4 C (0.6 F) higher than in the years before (likely change).
Suspected changes in the annual mean temperature at Waterville Wwtp, against neighbouring stations
Year
Shift (C)
Shift (F)
Strength
Neighbours
1911
+0.4
+0.6
likely
5
Possible change at the station (a move, a new instrument or a new site); the record is kept as measured. A "likely" change has a larger test statistic than a "possible" one. Neither says why the station differs from its neighbours. How changes are found, and the largest ones.
Download the Data
Data for Waterville Wwtp standing records by year: CSV or JSON. Field meanings are on the data page.
Data for Waterville Wwtp 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 2026-10-16 (16 October 2026). Records are computed by this site and are not official.