The Cherry Blossoms of Washington, D.C.
The trending of Peak Bloom Date
Each year, the National Cherry Blossom
Festival commemorates the 1912 gift of 3,000 cherry
trees from Mayor Yukio Ozaki of Tokyo to the city of
Washington, DC. The gift and annual celebration honor
the lasting friendship between the United States and
Japan and the continued close relationship between the
two countries.
In a simple ceremony on March 27, 1912, First
Lady Helen Herron Taft and Viscountess Chinda, wife
of the Japanese ambassador, planted the first two trees
from Japan on the north bank of the Tidal Basin in West
The Tidal Basin, Washington, DC / photo: John Manz
Potomac Park. These are the trees that now turn the Tidal
Basin into a cloud of pink each spring for all to enjoy.
First Lady Lady Bird Johnson accepted 3,800 more trees in 1965.
The Peak Bloom Date is defined as the day in which 70 percent of the blossoms of the Yoshino
Cherry (Prunus x yedoensis) trees are open. The date when the Yoshino cherry blossoms reach peak
bloom varies from year to year, depending on weather conditions. Cherry Blossom Festival dates are set
based on the average date of blooming (April 4), but nature is not always cooperative. Unseasonably
warm and/or cool temperatures have resulted in the Yoshino cherries reaching peak bloom as early as
March 15 (1990) and as late as April 18 (1958).
The following table is the historical recorded record of when the Peak Bloom Date occurred for
the Tidal Basin trees from 1921 to 2012. Included in this record are a series of extremes as mentioned
earlier. Your objective is to plot these data points on Excel and generate a regression line and equation for
the resulting trend. This trend will be used in class to discuss the effects of weather, climate, and climate
change on the budding phenophase of the Yoshino cherry.
Year
1921
1922
1923
1924
1925
1926
1927
1928
1929
1930
1931
1932
1933
1934
1935
1936
1937
1938
1939
1940
1941
1942
1943
Peak Bloom Date
Days after Jan. 1st
79
97
99
103
86
101
79
99
90
91
101
106
99
105
91
98
104
84
89
104
102
95
94
Year
1944
1945
1946
1947
1948
1949
1950
1951
1952
1953
1954
1955
1956
1957
1958
1959
1960
1961
1962
1963
1964
1965
1966
Peak Bloom Date
Days after Jan. 1st
100
79
82
102
88
88
99
96
100
86
96
92
97
98
108
96
105
92
97
93
102
105
95
Year
1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
Peak Bloom Date
Days after Jan. 1st
96
90
99
106
98
102
101
93
93
83
85
102
92
97
93
97
97
94
97
92
87
91
88
Year
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
Peak Bloom Date
Days after Jan. 1st
74
88
96
101
95
92
95
85
86
95
77
98
92
92
91
99
89
91
89
91
90
88
80