Record envelope, standing records and threshold days for Birch Hill Dam (USC00190666), Massachusetts, United States, with 79 years of record.
Key Facts for Birch Hill Dam
Birch Hill Dam (USC00190666) is a weather station in Massachusetts, United States at 42.63 latitude and -72.12 longitude, 261 m (855 ft) above sea level.
The station reports from 1948 to 2026, 79 years of record.
1,464 records set at Birch Hill Dam still stand.
Records are tracked for tmax, tmin, prcp, snow, snwd: an element needs 30 years of data to be eligible.
Birch Hill Dam set a monthly record daily precipitation of 108.7 mm (4.3 in) on 30 July 2026.
About the Station
Location: Massachusetts, United States, 42.63 latitude, -72.12 longitude.
Elevation: 261 m (855 ft).
Period of record: 1948 to 2026, 79 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 Birch Hill 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 Birch Hill Dam, with 2026 drawn through them
Month
Highest record high
Lowest record low
2026 highest maximum
2026 lowest minimum
Jan
18.9 C (66.0 F)
-36.7 C (-34.1 F)
n/a
n/a
Feb
22.2 C (72.0 F)
-33.3 C (-27.9 F)
n/a
n/a
Mar
27.8 C (82.0 F)
-28.3 C (-18.9 F)
n/a
n/a
Apr
32.8 C (91.0 F)
-14.4 C (6.1 F)
n/a
n/a
May
33.9 C (93.0 F)
-6.7 C (19.9 F)
n/a
n/a
Jun
36.1 C (97.0 F)
-2.8 C (27.0 F)
n/a
n/a
Jul
37.2 C (99.0 F)
1.1 C (34.0 F)
n/a
n/a
Aug
37.2 C (99.0 F)
-1.7 C (28.9 F)
n/a
n/a
Sep
36.7 C (98.1 F)
-6.7 C (19.9 F)
n/a
n/a
Oct
29.4 C (84.9 F)
-11.1 C (12.0 F)
n/a
n/a
Nov
26.1 C (79.0 F)
-20.6 C (-5.1 F)
n/a
n/a
Dec
20.6 C (69.1 F)
-31.7 C (-25.1 F)
n/a
n/a
Which Years Hold Standing Records
1,464 standing records
Year with most
1,464 records at Birch Hill Dam still stand. 1956 holds the most, with 38.
Standing records at Birch Hill Dam by the year they were set
Year set
Standing records
1948
13
1949
34
1950
30
1951
33
1952
11
1953
36
1954
33
1955
25
1956
38
1957
29
1958
15
1959
22
1960
8
1961
27
1962
22
1963
27
1964
32
1965
26
1966
19
1967
26
1968
24
1969
25
1970
9
1971
22
1972
16
1973
11
1974
26
1975
18
1976
32
1977
33
1978
16
1979
38
1980
13
1981
12
1982
27
1983
11
1984
18
1985
13
1986
18
1987
22
1988
23
1989
25
1990
17
1991
12
1992
12
1993
17
1994
11
1995
10
1996
9
1997
5
1998
9
1999
17
2000
14
2001
14
2002
24
2003
16
2004
11
2005
27
2006
21
2007
21
2008
7
2011
16
2012
20
2013
18
2014
14
2015
18
2016
16
2017
34
2018
27
2019
9
2020
21
2021
36
2022
3
All-Time Record Progression
7 new records
7 all-time records were set at Birch Hill Dam between 26 December 1980 and 12 August 2021. Each dot is a new record.
When Birch Hill Dam set new all-time records
Date
Kind
Detail
1980-12-26
Record low maximum temperature
Record low maximum temperature -20.6 C (-5.1 F)
1991-08-20
Record daily precipitation
Record daily precipitation 109.2 mm (4.3 in)
2001-02-06
Record daily snowfall
Record daily snowfall 61.0 cm (24.0 in)
2001-03-10
Record snow depth
Record snow depth 101.6 cm (40.0 in)
2004-09-18
Record daily precipitation
Record daily precipitation 121.9 mm (4.8 in)
2005-10-09
Record daily precipitation
Record daily precipitation 160.5 mm (6.3 in)
2021-08-12
Record high minimum temperature
Record high minimum temperature 23.9 C (75.0 F)
Wettest Day of Each Month
Oct: 160.5 mm (6.3 in)
The wettest day on record for each calendar month at Birch Hill Dam. The most was 160.5 mm (6.3 in) on 9 October 2005.
Record daily precipitation for each month at Birch Hill Dam
Month
Record daily precipitation (mm)
Date
Jan
69.3 mm (2.7 in)
13 January 2018
Feb
75.9 mm (3.0 in)
14 February 2008
Mar
94.0 mm (3.7 in)
7 March 2011
Apr
61.7 mm (2.4 in)
17 April 1996
May
83.3 mm (3.3 in)
30 May 1984
Jun
100.3 mm (3.9 in)
15 June 1960
Jul
108.7 mm (4.3 in)
30 July 2026
Aug
109.2 mm (4.3 in)
20 August 1991
Sep
121.9 mm (4.8 in)
18 September 2004
Oct
160.5 mm (6.3 in)
9 October 2005
Nov
77.5 mm (3.1 in)
26 November 1950
Dec
71.1 mm (2.8 in)
8 December 2011
Period of Record Coverage
1948 to 2022
Complete yearUnder 90 percent of days
73 years of record at Birch Hill Dam, 1948 to 2022. 15 years have data for under 90 percent of days and are left out of rankings: 1948, 1991, 1992, 1993, 1994, 1995, 1996, 1997 and others.
Cooler than the station meanWarmer than the station mean
One stripe for each of 59 complete years at Birch Hill Dam, 1950 to 2021. Blue stripes are years cooler than the station's own mean of 7.5 C (45.5 F); red stripes are warmer. The coolest year was 1978, at 5.9 C (42.5 F), and the warmest was 2021, at 9.7 C (49.4 F). The strongest colour marks a difference of 2.2 C (4.0 F).
Annual mean temperature at Birch Hill Dam as warming stripes, 1950 to 2021
Year
Annual mean temperature
Difference from the station mean
1950
7.4 C
-0.06 C
1951
7.6 C
+0.08 C
1952
8.1 C
+0.58 C
1953
9.3 C
+1.84 C
1954
8.0 C
+0.48 C
1955
8.1 C
+0.63 C
1956
7.3 C
-0.24 C
1957
8.3 C
+0.81 C
1958
7.0 C
-0.46 C
1959
8.4 C
+0.91 C
1960
7.7 C
+0.23 C
1961
7.9 C
+0.43 C
1962
6.9 C
-0.56 C
1963
7.2 C
-0.26 C
1964
7.7 C
+0.16 C
1965
7.4 C
-0.09 C
1966
7.6 C
+0.09 C
1967
7.3 C
-0.19 C
1968
7.5 C
-0.03 C
1969
7.9 C
+0.37 C
1970
7.1 C
-0.36 C
1971
6.4 C
-1.13 C
1972
6.1 C
-1.37 C
1973
8.0 C
+0.47 C
1974
6.6 C
-0.87 C
1975
6.9 C
-0.58 C
1976
6.1 C
-1.37 C
1977
6.5 C
-1.00 C
1978
5.9 C
-1.64 C
1979
7.4 C
-0.12 C
1980
6.5 C
-0.98 C
1981
6.9 C
-0.61 C
1982
6.5 C
-1.01 C
1983
7.6 C
+0.06 C
1984
7.2 C
-0.31 C
1985
6.7 C
-0.78 C
1986
6.7 C
-0.76 C
1987
6.8 C
-0.73 C
1988
6.4 C
-1.14 C
1989
6.2 C
-1.28 C
1990
8.0 C
+0.53 C
1996
7.2 C
-0.26 C
1999
8.3 C
+0.81 C
2002
7.9 C
+0.41 C
2004
6.5 C
-1.00 C
2005
7.3 C
-0.21 C
2006
8.3 C
+0.84 C
2007
7.3 C
-0.15 C
2011
8.3 C
+0.79 C
2012
9.5 C
+1.99 C
2013
7.9 C
+0.44 C
2014
7.3 C
-0.21 C
2015
7.6 C
+0.08 C
2016
8.8 C
+1.35 C
2017
8.4 C
+0.89 C
2018
8.3 C
+0.85 C
2019
7.8 C
+0.32 C
2020
8.9 C
+1.41 C
2021
9.7 C
+2.17 C
The fitted trend in annual mean temperature here over 1950 to 2021 is 0.10 C (0.00 to 0.20) per decade. The interval includes zero, so the trend is not clearly different from zero. In Fahrenheit: 0.17 F (-0.01 to 0.36) per decade. The slope is a straight line fitted to 59 complete years; the brackets give its 95 percent interval.
Fitted temperature trends per decade at Birch Hill Dam
Measure
Per decade (C)
Per decade (F)
Period
Complete years
Reading
Annual mean temperature
0.10 C (0.00 to 0.20) per decade
0.17 F (-0.01 to 0.36) per decade
1950 to 2021
59
Not clearly different from zero
Mean daily maximum
0.05 C (-0.04 to 0.14) per decade
0.1 F (-0.1 to 0.2) per decade
1950 to 2021
59
Not clearly different from zero
Mean daily minimum
0.15 C (0.02 to 0.28) per decade
0.26 F (0.03 to 0.50) per decade
1950 to 2021
59
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
1948 to 2026
Yearly extremes at Birch Hill Dam: the record and the median year
Measure
Record
Year of the record
Median year
Years with a value
Hottest day (TXx)
37.2 C (99.0 F)
1948
33.9 C (93.0 F)
73
Coldest night (TNn)
-36.7 C (-34.1 F)
1957
-27.8 C (-18.0 F)
73
Wettest day (Rx1day)
160.5 mm (6.3 in)
2005
60.2 mm (2.4 in)
77
Wettest five days (Rx5day)
191.7 mm (7.5 in)
2005
94.0 mm (3.7 in)
77
Longest dry spell (CDD)
38 days
2001
16 days
77
Hottest day (TXx)
The hottest day of the year at Birch Hill Dam, 1948 to 2026. The record is 37.2 C (99.0 F) in 1948, marked on the chart; the median year is 33.9 C (93.0 F).
Hottest day (TXx) at Birch Hill Dam by year
Year
Hottest day (TXx)
1948
37.2 C (99.0 F)
1949
35.0 C (95.0 F)
1950
32.2 C (90.0 F)
1951
30.6 C (87.1 F)
1952
34.4 C (93.9 F)
1953
36.7 C (98.1 F)
1954
32.8 C (91.0 F)
1955
35.6 C (96.1 F)
1956
33.9 C (93.0 F)
1957
33.3 C (91.9 F)
1958
32.8 C (91.0 F)
1959
33.9 C (93.0 F)
1960
31.7 C (89.1 F)
1961
32.2 C (90.0 F)
1962
33.3 C (91.9 F)
1963
35.0 C (95.0 F)
1964
35.0 C (95.0 F)
1965
33.9 C (93.0 F)
1966
35.0 C (95.0 F)
1967
32.8 C (91.0 F)
1968
35.6 C (96.1 F)
1969
33.3 C (91.9 F)
1970
33.3 C (91.9 F)
1971
32.2 C (90.0 F)
1972
33.3 C (91.9 F)
1973
33.9 C (93.0 F)
1974
32.2 C (90.0 F)
1975
36.1 C (97.0 F)
1976
33.9 C (93.0 F)
1977
33.9 C (93.0 F)
1978
33.9 C (93.0 F)
1979
34.4 C (93.9 F)
1980
33.9 C (93.0 F)
1981
33.3 C (91.9 F)
1982
33.3 C (91.9 F)
1983
33.3 C (91.9 F)
1984
33.3 C (91.9 F)
1985
32.2 C (90.0 F)
1986
32.8 C (91.0 F)
1987
34.4 C (93.9 F)
1988
35.0 C (95.0 F)
1989
33.3 C (91.9 F)
1990
32.8 C (91.0 F)
1991
35.0 C (95.0 F)
1992
33.3 C (91.9 F)
1993
36.1 C (97.0 F)
1994
35.6 C (96.1 F)
1995
35.6 C (96.1 F)
1996
31.7 C (89.1 F)
1997
33.3 C (91.9 F)
1998
32.2 C (90.0 F)
1999
34.4 C (93.9 F)
2000
32.8 C (91.0 F)
2001
34.4 C (93.9 F)
2002
35.6 C (96.1 F)
2003
32.8 C (91.0 F)
2004
31.1 C (88.0 F)
2005
35.0 C (95.0 F)
2006
35.6 C (96.1 F)
2007
33.9 C (93.0 F)
2008
35.6 C (96.1 F)
2011
37.2 C (99.0 F)
2012
35.0 C (95.0 F)
2013
34.4 C (93.9 F)
2014
32.2 C (90.0 F)
2015
33.3 C (91.9 F)
2016
33.9 C (93.0 F)
2017
33.9 C (93.0 F)
2018
36.1 C (97.0 F)
2019
34.4 C (93.9 F)
2020
34.4 C (93.9 F)
2021
35.6 C (96.1 F)
2022
24.4 C (75.9 F)
2023
n/a
2024
n/a
2025
n/a
2026
n/a
Coldest night (TNn)
The coldest night of the year at Birch Hill Dam, 1948 to 2026. The record is -36.7 C (-34.1 F) in 1957, marked on the chart; the median year is -27.8 C (-18.0 F).
Coldest night (TNn) at Birch Hill Dam by year
Year
Coldest night (TNn)
1948
-22.2 C (-8.0 F)
1949
-27.2 C (-17.0 F)
1950
-27.8 C (-18.0 F)
1951
-31.7 C (-25.1 F)
1952
-22.2 C (-8.0 F)
1953
-18.9 C (-2.0 F)
1954
-31.7 C (-25.1 F)
1955
-25.6 C (-14.1 F)
1956
-27.2 C (-17.0 F)
1957
-36.7 C (-34.1 F)
1958
-30.6 C (-23.1 F)
1959
-25.0 C (-13.0 F)
1960
-26.7 C (-16.1 F)
1961
-34.4 C (-29.9 F)
1962
-27.8 C (-18.0 F)
1963
-31.7 C (-25.1 F)
1964
-30.6 C (-23.1 F)
1965
-28.3 C (-18.9 F)
1966
-27.8 C (-18.0 F)
1967
-31.7 C (-25.1 F)
1968
-33.3 C (-27.9 F)
1969
-27.2 C (-17.0 F)
1970
-30.0 C (-22.0 F)
1971
-35.0 C (-31.0 F)
1972
-26.7 C (-16.1 F)
1973
-25.6 C (-14.1 F)
1974
-27.2 C (-17.0 F)
1975
-30.6 C (-23.1 F)
1976
-33.3 C (-27.9 F)
1977
-30.6 C (-23.1 F)
1978
-29.4 C (-20.9 F)
1979
-27.8 C (-18.0 F)
1980
-31.1 C (-24.0 F)
1981
-31.7 C (-25.1 F)
1982
-32.2 C (-26.0 F)
1983
-26.1 C (-15.0 F)
1984
-32.8 C (-27.0 F)
1985
-27.8 C (-18.0 F)
1986
-23.3 C (-9.9 F)
1987
-27.2 C (-17.0 F)
1988
-31.7 C (-25.1 F)
1989
-29.4 C (-20.9 F)
1990
-23.3 C (-9.9 F)
1991
-25.0 C (-13.0 F)
1992
-23.3 C (-9.9 F)
1993
-28.3 C (-18.9 F)
1994
-33.3 C (-27.9 F)
1995
-23.3 C (-9.9 F)
1996
-30.0 C (-22.0 F)
1997
-23.3 C (-9.9 F)
1998
-23.3 C (-9.9 F)
1999
-28.9 C (-20.0 F)
2000
-25.6 C (-14.1 F)
2001
-22.8 C (-9.0 F)
2002
-22.2 C (-8.0 F)
2003
-27.8 C (-18.0 F)
2004
-28.9 C (-20.0 F)
2005
-28.9 C (-20.0 F)
2006
-22.8 C (-9.0 F)
2007
-21.1 C (-6.0 F)
2008
-23.9 C (-11.0 F)
2011
-27.8 C (-18.0 F)
2012
-20.6 C (-5.1 F)
2013
-21.7 C (-7.1 F)
2014
-25.6 C (-14.1 F)
2015
-28.9 C (-20.0 F)
2016
-26.7 C (-16.1 F)
2017
-25.0 C (-13.0 F)
2018
-28.3 C (-18.9 F)
2019
-22.8 C (-9.0 F)
2020
-20.6 C (-5.1 F)
2021
-20.6 C (-5.1 F)
2022
-23.9 C (-11.0 F)
2023
n/a
2024
n/a
2025
n/a
2026
n/a
Wettest day (Rx1day)
The wettest day of the year at Birch Hill Dam, 1948 to 2026. The record is 160.5 mm (6.3 in) in 2005, marked on the chart; the median year is 60.2 mm (2.4 in).
Wettest day (Rx1day) at Birch Hill Dam by year
Year
Wettest day (Rx1day)
1948
51.3 mm (2.0 in)
1949
44.5 mm (1.8 in)
1950
77.5 mm (3.1 in)
1951
66.8 mm (2.6 in)
1952
70.9 mm (2.8 in)
1953
66.3 mm (2.6 in)
1954
69.1 mm (2.7 in)
1955
68.6 mm (2.7 in)
1956
57.2 mm (2.3 in)
1957
41.9 mm (1.6 in)
1958
39.4 mm (1.6 in)
1959
69.9 mm (2.8 in)
1960
100.3 mm (3.9 in)
1961
48.3 mm (1.9 in)
1962
62.7 mm (2.5 in)
1963
43.2 mm (1.7 in)
1964
49.0 mm (1.9 in)
1965
38.1 mm (1.5 in)
1966
39.9 mm (1.6 in)
1967
53.8 mm (2.1 in)
1968
44.5 mm (1.8 in)
1969
50.8 mm (2.0 in)
1970
51.6 mm (2.0 in)
1971
53.3 mm (2.1 in)
1972
67.8 mm (2.7 in)
1973
61.7 mm (2.4 in)
1974
56.1 mm (2.2 in)
1975
55.1 mm (2.2 in)
1976
41.9 mm (1.6 in)
1977
44.2 mm (1.7 in)
1978
51.6 mm (2.0 in)
1979
67.6 mm (2.7 in)
1980
60.2 mm (2.4 in)
1981
43.2 mm (1.7 in)
1982
58.4 mm (2.3 in)
1983
47.2 mm (1.9 in)
1984
83.3 mm (3.3 in)
1985
60.2 mm (2.4 in)
1986
64.8 mm (2.6 in)
1987
49.5 mm (1.9 in)
1988
61.0 mm (2.4 in)
1989
85.1 mm (3.4 in)
1990
57.2 mm (2.3 in)
1991
109.2 mm (4.3 in)
1992
44.5 mm (1.8 in)
1993
44.5 mm (1.8 in)
1994
48.3 mm (1.9 in)
1995
83.1 mm (3.3 in)
1996
63.5 mm (2.5 in)
1997
55.9 mm (2.2 in)
1998
64.3 mm (2.5 in)
1999
97.8 mm (3.9 in)
2000
100.3 mm (3.9 in)
2001
53.3 mm (2.1 in)
2002
57.2 mm (2.3 in)
2003
52.1 mm (2.1 in)
2004
121.9 mm (4.8 in)
2005
160.5 mm (6.3 in)
2006
68.6 mm (2.7 in)
2007
44.7 mm (1.8 in)
2008
75.9 mm (3.0 in)
2011
94.0 mm (3.7 in)
2012
67.1 mm (2.6 in)
2013
61.2 mm (2.4 in)
2014
70.9 mm (2.8 in)
2015
61.5 mm (2.4 in)
2016
50.3 mm (2.0 in)
2017
71.1 mm (2.8 in)
2018
70.9 mm (2.8 in)
2019
65.0 mm (2.6 in)
2020
41.4 mm (1.6 in)
2021
68.1 mm (2.7 in)
2022
68.8 mm (2.7 in)
2023
37.1 mm (1.5 in)
2024
43.9 mm (1.7 in)
2025
41.9 mm (1.6 in)
2026
108.7 mm (4.3 in)
Wettest five days (Rx5day)
The wettest five days of the year at Birch Hill Dam, 1948 to 2026. The record is 191.7 mm (7.5 in) in 2005, marked on the chart; the median year is 94.0 mm (3.7 in).
Wettest five days (Rx5day) at Birch Hill Dam by year
Year
Wettest five days (Rx5day)
1948
66.6 mm (2.6 in)
1949
63.5 mm (2.5 in)
1950
90.2 mm (3.6 in)
1951
75.2 mm (3.0 in)
1952
97.6 mm (3.8 in)
1953
74.9 mm (2.9 in)
1954
78.2 mm (3.1 in)
1955
164.1 mm (6.5 in)
1956
87.7 mm (3.5 in)
1957
60.5 mm (2.4 in)
1958
61.0 mm (2.4 in)
1959
85.6 mm (3.4 in)
1960
130.9 mm (5.2 in)
1961
59.2 mm (2.3 in)
1962
117.4 mm (4.6 in)
1963
60.1 mm (2.4 in)
1964
68.6 mm (2.7 in)
1965
66.3 mm (2.6 in)
1966
58.4 mm (2.3 in)
1967
77.4 mm (3.0 in)
1968
73.4 mm (2.9 in)
1969
97.1 mm (3.8 in)
1970
91.0 mm (3.6 in)
1971
73.4 mm (2.9 in)
1972
81.0 mm (3.2 in)
1973
113.6 mm (4.5 in)
1974
66.3 mm (2.6 in)
1975
151.0 mm (5.9 in)
1976
97.5 mm (3.8 in)
1977
79.0 mm (3.1 in)
1978
59.0 mm (2.3 in)
1979
112.1 mm (4.4 in)
1980
81.8 mm (3.2 in)
1981
89.6 mm (3.5 in)
1982
104.3 mm (4.1 in)
1983
63.8 mm (2.5 in)
1984
184.2 mm (7.3 in)
1985
60.2 mm (2.4 in)
1986
94.0 mm (3.7 in)
1987
96.7 mm (3.8 in)
1988
111.1 mm (4.4 in)
1989
124.5 mm (4.9 in)
1990
112.8 mm (4.4 in)
1991
189.9 mm (7.5 in)
1992
55.7 mm (2.2 in)
1993
89.2 mm (3.5 in)
1994
107.2 mm (4.2 in)
1995
103.1 mm (4.1 in)
1996
113.3 mm (4.5 in)
1997
79.6 mm (3.1 in)
1998
103.4 mm (4.1 in)
1999
108.5 mm (4.3 in)
2000
106.6 mm (4.2 in)
2001
90.6 mm (3.6 in)
2002
74.5 mm (2.9 in)
2003
83.5 mm (3.3 in)
2004
121.9 mm (4.8 in)
2005
191.7 mm (7.5 in)
2006
95.9 mm (3.8 in)
2007
97.9 mm (3.9 in)
2008
116.1 mm (4.6 in)
2011
107.9 mm (4.2 in)
2012
105.9 mm (4.2 in)
2013
102.4 mm (4.0 in)
2014
101.1 mm (4.0 in)
2015
102.2 mm (4.0 in)
2016
83.8 mm (3.3 in)
2017
149.6 mm (5.9 in)
2018
97.5 mm (3.8 in)
2019
75.4 mm (3.0 in)
2020
74.6 mm (2.9 in)
2021
98.3 mm (3.9 in)
2022
95.1 mm (3.7 in)
2023
70.1 mm (2.8 in)
2024
104.7 mm (4.1 in)
2025
57.2 mm (2.3 in)
2026
113.1 mm (4.5 in)
Longest dry spell (CDD)
The longest dry spell of the year at Birch Hill Dam, 1948 to 2026. The record is 38 days in 2001, marked on the chart; the median year is 16 days.
Longest dry spell (CDD) at Birch Hill Dam by year
Year
Longest dry spell (CDD)
1948
17 days
1949
25 days
1950
16 days
1951
14 days
1952
25 days
1953
15 days
1954
14 days
1955
25 days
1956
15 days
1957
19 days
1958
21 days
1959
14 days
1960
12 days
1961
17 days
1962
12 days
1963
27 days
1964
19 days
1965
20 days
1966
29 days
1967
11 days
1968
18 days
1969
13 days
1970
16 days
1971
13 days
1972
13 days
1973
15 days
1974
15 days
1975
25 days
1976
20 days
1977
14 days
1978
17 days
1979
18 days
1980
23 days
1981
14 days
1982
17 days
1983
17 days
1984
19 days
1985
14 days
1986
12 days
1987
19 days
1988
15 days
1989
12 days
1990
14 days
1991
16 days
1992
12 days
1993
13 days
1994
14 days
1995
29 days
1996
31 days
1997
18 days
1998
19 days
1999
19 days
2000
11 days
2001
38 days
2002
12 days
2003
9 days
2004
17 days
2005
13 days
2006
17 days
2007
25 days
2008
14 days
2011
11 days
2012
19 days
2013
13 days
2014
18 days
2015
19 days
2016
17 days
2017
9 days
2018
14 days
2019
9 days
2020
19 days
2021
16 days
2022
20 days
2023
25 days
2024
11 days
2025
15 days
2026
10 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
59 years with a frost
Across 59 years with a frost, the median last spring frost at Birch Hill Dam falls on 21 May and the median first autumn frost on 18 September, which leaves a median of 119 days between them.
Fitted over all years, the growing season changes by +6.1 days per decade at this station.
Frost dates and growing season at Birch Hill Dam
Measure
Median, all years
Earliest period
Recent period (1979 to 2021)
Recent against earliest
Fitted trend
Last spring frost
21 May
n/a
14 May
n/a
-2.7 days per decade
First autumn frost
18 September
n/a
25 September
n/a
+3.4 days per decade
Growing days
119 days
n/a
136 days
n/a
+6.1 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
64 years, 1949 to 2018
A day with at least 57.6 mm (2.3 in) of rain is expected about once in 2 years. A day with at least 146.2 mm (5.8 in) of rain is expected about once in 100 years.
Rainfall return levels at Birch Hill 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
57.6 mm (2.3 in)
5 years
74.5 mm (2.9 in)
10 years
88.0 mm (3.5 in)
25 years
108.3 mm (4.3 in)
50 years
126.0 mm (5.0 in)
100 years
146.2 mm (5.8 in)
Longer than the 64 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, 64 years of values from 1949 to 2018.
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: 160.5 mm (6.3 in) in 2005; 121.9 mm (4.8 in) in 2004; 109.2 mm (4.3 in) in 1991.
Station Changes
1 suspected
One change was suspected in the annual mean temperature of Birch Hill Dam, at 2006. Each is measured against neighbouring stations.
Relative to 5 neighbouring stations, the station's annual mean temperature from 2006 ran 0.4 C (0.6 F) higher than in the years before (likely change).
Suspected changes in the annual mean temperature at Birch Hill Dam, against neighbouring stations
Year
Shift (C)
Shift (F)
Strength
Neighbours
2006
+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.
Climate Twins
2004 to 2021 against 1961 to 1990
Over 2004 to 2021, Birch Hill Dam had a mean temperature of 8.1 C (46.6 F) and 1,212.2 mm (47.7 in) of rain a year. The 3 stations whose 1961 to 1990 climate was closest to that are Sanford 2 NNW (United States, 143 km away), Lewiston (United States, 224 km away) and Utica Oneida Co AP (United States, 272 km away).
Climate twins of Birch Hill Dam: stations whose 1961 to 1990 climate is closest to its 2004 to 2021 climate
Twins are stations, not cities. A twin is one of the three stations at least 100 km away whose earlier climate is closest to this station's recent one, so a close match does not mean the two places look alike in other ways. A station move or a gap in a record can change that station's averages. The list describes past climate; it is not a forecast and does not say what caused any change. How twins are found, and a search for any station.
Download the Data
Data for Birch Hill Dam standing records by year: CSV or JSON. Field meanings are on the data page.
Data for Birch Hill 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 2026-10-13 (13 October 2026). Records are computed by this site and are not official.