Record envelope, standing records and threshold days for Shepaug Dam (USC00067373), Connecticut, United States, with 67 years of record.
Key Facts for Shepaug Dam
Shepaug Dam (USC00067373) is a weather station in Connecticut, United States at 41.72 latitude and -73.30 longitude, 256 m (840 ft) above sea level.
The station reports from 1948 to 2014, 67 years of record.
1,464 records set at Shepaug Dam still stand.
Records are tracked for tmax, tmin, prcp, snow, snwd: an element needs 30 years of data to be eligible.
Shepaug Dam set a daily record precipitation of 65.3 mm (2.6 in) on 19 June 2013.
About the Station
Location: Connecticut, United States, 41.72 latitude, -73.30 longitude.
Elevation: 256 m (840 ft).
Period of record: 1948 to 2014, 67 years.
Eligible elements: tmax, tmin, prcp, snow, snwd.
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 Shepaug 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 Shepaug Dam, with 2026 drawn through them
Month
Highest record high
Lowest record low
2026 highest maximum
2026 lowest minimum
Jan
20.0 C (68.0 F)
-32.8 C (-27.0 F)
n/a
n/a
Feb
21.1 C (70.0 F)
-28.9 C (-20.0 F)
n/a
n/a
Mar
29.4 C (84.9 F)
-23.9 C (-11.0 F)
n/a
n/a
Apr
32.8 C (91.0 F)
-13.9 C (7.0 F)
n/a
n/a
May
32.8 C (91.0 F)
-5.0 C (23.0 F)
n/a
n/a
Jun
33.3 C (91.9 F)
0.6 C (33.1 F)
n/a
n/a
Jul
35.0 C (95.0 F)
5.6 C (42.1 F)
n/a
n/a
Aug
35.6 C (96.1 F)
2.2 C (36.0 F)
n/a
n/a
Sep
35.0 C (95.0 F)
-2.8 C (27.0 F)
n/a
n/a
Oct
29.4 C (84.9 F)
-6.7 C (19.9 F)
n/a
n/a
Nov
26.1 C (79.0 F)
-15.0 C (5.0 F)
n/a
n/a
Dec
20.0 C (68.0 F)
-27.2 C (-17.0 F)
n/a
n/a
Which Years Hold Standing Records
1,464 standing records
Year with most
1,464 records at Shepaug Dam still stand. 1949 holds the most, with 51.
Standing records at Shepaug Dam by the year they were set
Year set
Standing records
1949
51
1950
16
1951
23
1952
14
1953
24
1954
19
1955
21
1956
32
1957
29
1958
25
1959
50
1960
26
1961
28
1962
31
1963
42
1964
28
1965
35
1966
25
1967
33
1968
28
1969
20
1970
17
1971
25
1972
24
1973
20
1974
35
1975
32
1976
37
1977
21
1978
27
1979
50
1980
22
1981
27
1982
27
1983
21
1984
30
1985
19
1986
18
1987
30
1988
28
1989
34
1990
36
1991
38
1992
21
1993
23
1994
20
1995
21
1996
24
1997
19
1998
19
1999
10
2000
25
2001
29
2002
33
2003
2
All-Time Record Progression
2 new records
2 all-time records were set at Shepaug Dam between 12 February 1983 and 13 December 1992. Each dot is a new record.
When Shepaug Dam set new all-time records
Date
Kind
Detail
1983-02-12
Record daily snowfall
Record daily snowfall 50.8 cm (20.0 in)
1992-12-13
Record snow depth
Record snow depth 50.8 cm (20.0 in)
Wettest Day of Each Month
Aug: 217.9 mm (8.6 in)
The wettest day on record for each calendar month at Shepaug Dam. The most was 217.9 mm (8.6 in) on 19 August 1955.
Record daily precipitation for each month at Shepaug Dam
Month
Record daily precipitation (mm)
Date
Jan
68.6 mm (2.7 in)
26 January 1978
Feb
62.5 mm (2.5 in)
3 February 1973
Mar
87.6 mm (3.4 in)
22 March 1980
Apr
102.9 mm (4.1 in)
5 April 1987
May
76.2 mm (3.0 in)
25 May 1979
Jun
97.8 mm (3.9 in)
6 June 1982
Jul
109.2 mm (4.3 in)
16 July 2000
Aug
217.9 mm (8.6 in)
19 August 1955
Sep
135.9 mm (5.4 in)
17 September 1999
Oct
107.2 mm (4.2 in)
15 October 1955
Nov
73.2 mm (2.9 in)
26 November 1950
Dec
98.8 mm (3.9 in)
31 December 1948
Period of Record Coverage
1949 to 2003
Complete yearUnder 90 percent of days
55 years of record at Shepaug Dam, 1949 to 2003. 11 years have data for under 90 percent of days and are left out of rankings: 1949, 1950, 1992, 1996, 1997, 1998, 1999, 2000 and others.
Cooler than the station meanWarmer than the station mean
One stripe for each of 40 complete years at Shepaug Dam, 1951 to 1995. Blue stripes are years cooler than the station's own mean of 8.7 C (47.7 F); red stripes are warmer. The coolest year was 1958, at 7.6 C (45.6 F), and the warmest was 1991, at 9.9 C (49.8 F). The strongest colour marks a difference of 1.3 C (2.3 F).
Annual mean temperature at Shepaug Dam as warming stripes, 1951 to 1995
Year
Annual mean temperature
Difference from the station mean
1951
8.9 C
+0.20 C
1952
9.1 C
+0.37 C
1953
9.9 C
+1.19 C
1954
8.9 C
+0.20 C
1955
8.8 C
+0.13 C
1957
9.0 C
+0.29 C
1958
7.6 C
-1.12 C
1959
9.6 C
+0.85 C
1960
8.5 C
-0.21 C
1962
7.9 C
-0.78 C
1965
8.4 C
-0.34 C
1966
8.8 C
+0.08 C
1967
8.2 C
-0.46 C
1968
8.6 C
-0.09 C
1969
8.6 C
-0.07 C
1970
8.6 C
-0.11 C
1971
8.9 C
+0.22 C
1972
8.4 C
-0.32 C
1973
9.9 C
+1.16 C
1974
8.5 C
-0.16 C
1975
9.0 C
+0.31 C
1976
8.2 C
-0.55 C
1977
8.6 C
-0.14 C
1978
7.7 C
-1.03 C
1979
8.9 C
+0.17 C
1980
8.4 C
-0.28 C
1981
8.8 C
+0.14 C
1982
8.4 C
-0.28 C
1983
9.3 C
+0.58 C
1984
9.2 C
+0.48 C
1985
9.0 C
+0.26 C
1986
8.8 C
+0.05 C
1987
9.0 C
+0.32 C
1988
8.5 C
-0.17 C
1989
8.0 C
-0.75 C
1990
9.7 C
+1.00 C
1991
9.9 C
+1.21 C
1993
8.1 C
-0.65 C
1994
8.0 C
-0.73 C
1995
7.7 C
-1.02 C
The fitted trend in annual mean temperature here over 1951 to 1995 is -0.1 C (-0.2 to 0.1) per decade. The interval includes zero, so the trend is not clearly different from zero. In Fahrenheit: -0.1 F (-0.4 to 0.2) per decade. The slope is a straight line fitted to 40 complete years; the brackets give its 95 percent interval.
Fitted temperature trends per decade at Shepaug Dam
Measure
Per decade (C)
Per decade (F)
Period
Complete years
Reading
Annual mean temperature
-0.1 C (-0.2 to 0.1) per decade
-0.1 F (-0.4 to 0.2) per decade
1951 to 1995
40
Not clearly different from zero
Mean daily maximum
0.1 C (-0.1 to 0.2) per decade
0.2 F (-0.1 to 0.4) per decade
1951 to 1995
40
Not clearly different from zero
Mean daily minimum
-0.21 C (-0.40 to -0.02) per decade
-0.38 F (-0.72 to -0.03) per decade
1951 to 1995
40
Fall
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
1948 to 2014
Yearly extremes at Shepaug Dam: the record and the median year
Measure
Record
Year of the record
Median year
Years with a value
Hottest day (TXx)
35.6 C (96.1 F)
1955
32.8 C (91.0 F)
55
Coldest night (TNn)
-32.8 C (-27.0 F)
1961
-23.3 C (-9.9 F)
55
Wettest day (Rx1day)
217.9 mm (8.6 in)
1955
66.0 mm (2.6 in)
60
Wettest five days (Rx5day)
285.5 mm (11.2 in)
1955
99.7 mm (3.9 in)
60
Longest dry spell (CDD)
30 days
1980
16 days
60
Hottest day (TXx)
The hottest day of the year at Shepaug Dam, 1948 to 2014. The record is 35.6 C (96.1 F) in 1955, marked on the chart; the median year is 32.8 C (91.0 F).
Hottest day (TXx) at Shepaug Dam by year
Year
Hottest day (TXx)
1948
n/a
1949
33.3 C (91.9 F)
1950
29.4 C (84.9 F)
1951
31.7 C (89.1 F)
1952
32.2 C (90.0 F)
1953
35.0 C (95.0 F)
1954
32.2 C (90.0 F)
1955
35.6 C (96.1 F)
1956
31.1 C (88.0 F)
1957
33.9 C (93.0 F)
1958
29.4 C (84.9 F)
1959
33.3 C (91.9 F)
1960
30.6 C (87.1 F)
1961
32.8 C (91.0 F)
1962
32.8 C (91.0 F)
1963
32.8 C (91.0 F)
1964
33.3 C (91.9 F)
1965
33.3 C (91.9 F)
1966
34.4 C (93.9 F)
1967
33.3 C (91.9 F)
1968
33.9 C (93.0 F)
1969
32.8 C (91.0 F)
1970
32.2 C (90.0 F)
1971
31.7 C (89.1 F)
1972
33.3 C (91.9 F)
1973
32.8 C (91.0 F)
1974
32.8 C (91.0 F)
1975
35.0 C (95.0 F)
1976
32.8 C (91.0 F)
1977
34.4 C (93.9 F)
1978
33.3 C (91.9 F)
1979
32.2 C (90.0 F)
1980
34.4 C (93.9 F)
1981
34.4 C (93.9 F)
1982
34.4 C (93.9 F)
1983
33.3 C (91.9 F)
1984
33.3 C (91.9 F)
1985
31.1 C (88.0 F)
1986
33.3 C (91.9 F)
1987
32.8 C (91.0 F)
1988
35.0 C (95.0 F)
1989
32.8 C (91.0 F)
1990
32.2 C (90.0 F)
1991
35.0 C (95.0 F)
1992
30.0 C (86.0 F)
1993
33.3 C (91.9 F)
1994
32.2 C (90.0 F)
1995
35.0 C (95.0 F)
1996
32.2 C (90.0 F)
1997
31.1 C (88.0 F)
1998
30.6 C (87.1 F)
1999
32.2 C (90.0 F)
2000
30.6 C (87.1 F)
2001
35.6 C (96.1 F)
2002
32.8 C (91.0 F)
2003
13.3 C (55.9 F)
2011
n/a
2012
n/a
2013
n/a
2014
n/a
Coldest night (TNn)
The coldest night of the year at Shepaug Dam, 1948 to 2014. The record is -32.8 C (-27.0 F) in 1961, marked on the chart; the median year is -23.3 C (-9.9 F).
Coldest night (TNn) at Shepaug Dam by year
Year
Coldest night (TNn)
1948
n/a
1949
-19.4 C (-2.9 F)
1950
-24.4 C (-11.9 F)
1951
-22.8 C (-9.0 F)
1952
-18.9 C (-2.0 F)
1953
-15.6 C (3.9 F)
1954
-23.3 C (-9.9 F)
1955
-25.0 C (-13.0 F)
1956
-20.0 C (-4.0 F)
1957
-17.8 C (0.0 F)
1958
-25.0 C (-13.0 F)
1959
-19.4 C (-2.9 F)
1960
-23.9 C (-11.0 F)
1961
-32.8 C (-27.0 F)
1962
-25.0 C (-13.0 F)
1963
-26.7 C (-16.1 F)
1964
-22.2 C (-8.0 F)
1965
-27.2 C (-17.0 F)
1966
-21.7 C (-7.1 F)
1967
-23.9 C (-11.0 F)
1968
-22.2 C (-8.0 F)
1969
-20.6 C (-5.1 F)
1970
-24.4 C (-11.9 F)
1971
-28.9 C (-20.0 F)
1972
-22.8 C (-9.0 F)
1973
-20.6 C (-5.1 F)
1974
-21.1 C (-6.0 F)
1975
-23.3 C (-9.9 F)
1976
-23.9 C (-11.0 F)
1977
-22.8 C (-9.0 F)
1978
-22.2 C (-8.0 F)
1979
-24.4 C (-11.9 F)
1980
-27.2 C (-17.0 F)
1981
-30.0 C (-22.0 F)
1982
-28.9 C (-20.0 F)
1983
-22.8 C (-9.0 F)
1984
-31.1 C (-24.0 F)
1985
-25.6 C (-14.1 F)
1986
-20.6 C (-5.1 F)
1987
-25.0 C (-13.0 F)
1988
-27.2 C (-17.0 F)
1989
-23.9 C (-11.0 F)
1990
-23.3 C (-9.9 F)
1991
-22.2 C (-8.0 F)
1992
-20.0 C (-4.0 F)
1993
-25.0 C (-13.0 F)
1994
-29.4 C (-20.9 F)
1995
-26.7 C (-16.1 F)
1996
-25.0 C (-13.0 F)
1997
-17.8 C (0.0 F)
1998
-19.4 C (-2.9 F)
1999
-20.6 C (-5.1 F)
2000
-22.2 C (-8.0 F)
2001
-16.7 C (1.9 F)
2002
-23.3 C (-9.9 F)
2003
-27.2 C (-17.0 F)
2011
n/a
2012
n/a
2013
n/a
2014
n/a
Wettest day (Rx1day)
The wettest day of the year at Shepaug Dam, 1948 to 2014. The record is 217.9 mm (8.6 in) in 1955, marked on the chart; the median year is 66.0 mm (2.6 in).
Wettest day (Rx1day) at Shepaug Dam by year
Year
Wettest day (Rx1day)
1948
98.8 mm (3.9 in)
1949
47.2 mm (1.9 in)
1950
73.2 mm (2.9 in)
1951
65.3 mm (2.6 in)
1952
73.7 mm (2.9 in)
1953
70.4 mm (2.8 in)
1954
114.3 mm (4.5 in)
1955
217.9 mm (8.6 in)
1956
65.5 mm (2.6 in)
1957
66.0 mm (2.6 in)
1958
61.0 mm (2.4 in)
1959
55.4 mm (2.2 in)
1960
52.6 mm (2.1 in)
1961
39.1 mm (1.5 in)
1962
43.2 mm (1.7 in)
1963
46.7 mm (1.8 in)
1964
36.8 mm (1.4 in)
1965
41.4 mm (1.6 in)
1966
42.9 mm (1.7 in)
1967
44.2 mm (1.7 in)
1968
59.7 mm (2.4 in)
1969
82.0 mm (3.2 in)
1970
40.9 mm (1.6 in)
1971
103.4 mm (4.1 in)
1972
53.3 mm (2.1 in)
1973
95.3 mm (3.8 in)
1974
73.7 mm (2.9 in)
1975
101.6 mm (4.0 in)
1976
129.5 mm (5.1 in)
1977
53.3 mm (2.1 in)
1978
68.6 mm (2.7 in)
1979
76.2 mm (3.0 in)
1980
87.6 mm (3.4 in)
1981
53.3 mm (2.1 in)
1982
97.8 mm (3.9 in)
1983
66.0 mm (2.6 in)
1984
74.9 mm (2.9 in)
1985
68.6 mm (2.7 in)
1986
66.0 mm (2.6 in)
1987
102.9 mm (4.1 in)
1988
59.7 mm (2.4 in)
1989
55.9 mm (2.2 in)
1990
78.7 mm (3.1 in)
1991
67.3 mm (2.6 in)
1992
62.2 mm (2.4 in)
1993
63.5 mm (2.5 in)
1994
62.2 mm (2.4 in)
1995
69.9 mm (2.8 in)
1996
59.7 mm (2.4 in)
1997
66.0 mm (2.6 in)
1998
71.1 mm (2.8 in)
1999
135.9 mm (5.4 in)
2000
109.2 mm (4.3 in)
2001
77.5 mm (3.1 in)
2002
48.3 mm (1.9 in)
2003
47.0 mm (1.9 in)
2011
67.6 mm (2.7 in)
2012
41.9 mm (1.6 in)
2013
65.3 mm (2.6 in)
2014
14.0 mm (0.6 in)
Wettest five days (Rx5day)
The wettest five days of the year at Shepaug Dam, 1948 to 2014. The record is 285.5 mm (11.2 in) in 1955, marked on the chart; the median year is 99.7 mm (3.9 in).
Wettest five days (Rx5day) at Shepaug Dam by year
Year
Wettest five days (Rx5day)
1948
209.5 mm (8.2 in)
1949
215.6 mm (8.5 in)
1950
85.9 mm (3.4 in)
1951
103.1 mm (4.1 in)
1952
86.9 mm (3.4 in)
1953
121.0 mm (4.8 in)
1954
149.4 mm (5.9 in)
1955
285.5 mm (11.2 in)
1956
80.0 mm (3.1 in)
1957
89.2 mm (3.5 in)
1958
126.0 mm (5.0 in)
1959
78.5 mm (3.1 in)
1960
97.6 mm (3.8 in)
1961
62.0 mm (2.4 in)
1962
49.0 mm (1.9 in)
1963
72.4 mm (2.9 in)
1964
56.4 mm (2.2 in)
1965
49.0 mm (1.9 in)
1966
74.7 mm (2.9 in)
1967
66.3 mm (2.6 in)
1968
102.4 mm (4.0 in)
1969
175.5 mm (6.9 in)
1970
90.4 mm (3.6 in)
1971
112.5 mm (4.4 in)
1972
94.4 mm (3.7 in)
1973
135.2 mm (5.3 in)
1974
80.5 mm (3.2 in)
1975
228.6 mm (9.0 in)
1976
148.7 mm (5.9 in)
1977
115.2 mm (4.5 in)
1978
76.2 mm (3.0 in)
1979
119.4 mm (4.7 in)
1980
127.0 mm (5.0 in)
1981
110.5 mm (4.4 in)
1982
140.9 mm (5.5 in)
1983
104.1 mm (4.1 in)
1984
208.2 mm (8.2 in)
1985
123.2 mm (4.9 in)
1986
97.8 mm (3.9 in)
1987
130.9 mm (5.2 in)
1988
94.0 mm (3.7 in)
1989
127.0 mm (5.0 in)
1990
142.2 mm (5.6 in)
1991
156.2 mm (6.1 in)
1992
78.7 mm (3.1 in)
1993
85.1 mm (3.4 in)
1994
118.1 mm (4.6 in)
1995
96.6 mm (3.8 in)
1996
83.9 mm (3.3 in)
1997
67.3 mm (2.6 in)
1998
101.6 mm (4.0 in)
1999
179.1 mm (7.1 in)
2000
109.2 mm (4.3 in)
2001
97.3 mm (3.8 in)
2002
83.9 mm (3.3 in)
2003
44.4 mm (1.7 in)
2011
118.4 mm (4.7 in)
2012
62.5 mm (2.5 in)
2013
87.2 mm (3.4 in)
2014
15.3 mm (0.6 in)
Longest dry spell (CDD)
The longest dry spell of the year at Shepaug Dam, 1948 to 2014. The record is 30 days in 1980, marked on the chart; the median year is 16 days.
Longest dry spell (CDD) at Shepaug Dam by year
Year
Longest dry spell (CDD)
1948
14 days
1949
27 days
1950
17 days
1951
12 days
1952
21 days
1953
22 days
1954
11 days
1955
14 days
1956
17 days
1957
22 days
1958
16 days
1959
12 days
1960
18 days
1961
18 days
1962
14 days
1963
23 days
1964
27 days
1965
16 days
1966
21 days
1967
18 days
1968
26 days
1969
17 days
1970
14 days
1971
17 days
1972
16 days
1973
15 days
1974
12 days
1975
16 days
1976
18 days
1977
22 days
1978
14 days
1979
13 days
1980
30 days
1981
18 days
1982
21 days
1983
15 days
1984
17 days
1985
19 days
1986
16 days
1987
19 days
1988
15 days
1989
13 days
1990
12 days
1991
14 days
1992
15 days
1993
11 days
1994
11 days
1995
18 days
1996
13 days
1997
14 days
1998
13 days
1999
17 days
2000
15 days
2001
18 days
2002
14 days
2003
23 days
2011
16 days
2012
20 days
2013
17 days
2014
7 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
40 years with a frost
Across 40 years with a frost, the median last spring frost at Shepaug Dam falls on 8 May and the median first autumn frost on 8 October, which leaves a median of 155 days between them.
Fitted over all years, the growing season changes by -2.3 days per decade at this station.
Frost dates and growing season at Shepaug Dam
Measure
Median, all years
Earliest period
Recent period (1965 to 1995)
Recent against earliest
Fitted trend
Last spring frost
8 May
n/a
8 May
n/a
+1.2 days per decade
First autumn frost
8 October
n/a
9 October
n/a
-1.2 days per decade
Growing days
155 days
n/a
154 days
n/a
-2.3 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
47 years, 1949 to 2012
A day with at least 63.0 mm (2.5 in) of rain is expected about once in 2 years. A day with at least 182.4 mm (7.2 in) of rain is expected about once in 100 years.
Rainfall return levels at Shepaug 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
63.0 mm (2.5 in)
5 years
85.7 mm (3.4 in)
10 years
103.8 mm (4.1 in)
25 years
131.1 mm (5.2 in)
50 years
155.0 mm (6.1 in)
Longer than the 47 years of record
100 years
182.4 mm (7.2 in)
Longer than the 47 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, 47 years of values from 1949 to 2012.
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: 217.9 mm (8.6 in) in 1955; 129.5 mm (5.1 in) in 1976; 114.3 mm (4.5 in) in 1954.
Station Changes
No change in the annual mean temperature of this station was found against its neighbours.
Download the Data
Data for Shepaug Dam standing records by year: CSV or JSON. Field meanings are on the data page.
Data for Shepaug 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 2026-10-14 (14 October 2026). Records are computed by this site and are not official.