1922 to Present at the WSU Tree Fruit Research & Extension Center Wenatchee, WA

Updated by Tianna DuPont, WSU Extension April 28; from Tim Smith WSU Extension emeritus.

The date of full bloom at the WSU Tree Fruit Research and Extension Center is used as a relative comparison of one year to another. The 91 year average date of Red Delicious apple full bloom at WSU TFREC is April 27. The earliest Full Bloom date of all time at this site of April 9 was recorded in 2015 and tied for earliest again in 2016.  The bloom date for 2017 was May 1.

Daily high temperatures are used to predict bloom based on degree days (DD) above 43℉. As of April 27, Bloom DD in Wenatchee (TFREC) were 778 DD and 902 DD in Mattawa which predict first pink and full pink. Actual maturity is first bloom in Wenatchee on the TFREC sentinel trees.  920 DD predict full bloom. This is significantly later than 2016 where Wenatchee was already at full bloom April 9. However, this is only slightly behind the long term average with full bloom at April 27 in Wenatchee. As always look at the trees. Models are never perfect.

Red Delicious Apple Historical Full Bloom recorded in Wenatchee WA

Bloom by Year  Earliest to Latest
2016 9-Apr 2016 9-Apr
2015 9-Apr 2015 9-Apr
2014 21-Apr 1934 11-Apr
2013 20-Apr 2004 13-Apr
2012 25-Apr 1992 14-Apr
2011 7-May 1990 15-Apr
2010 23-Apr 1994 16-Apr
2009 1-May 1947 18-Apr
2008 4-May 1941 18-Apr
2007 26-Apr 2000 19-Apr
2006 28-Apr 1988 19-Apr
2005 22-Apr 1940 19-Apr
2004 13-Apr 1930 19-Apr
2003 22-Apr 2013 20-Apr
2002 28-Apr 2014 21-Apr
2001 27-Apr 2005 22-Apr
2000 19-Apr 2003 22-Apr
1999 27-Apr 1998 22-Apr
1998 22-Apr 1987 22-Apr
1997 2-May 2010 23-Apr
1996 26-Apr 1981 23-Apr
1995 25-Apr 1977 23-Apr
1994 16-Apr 1973 23-Apr
1993 7-May 1991 24-Apr
1992 14-Apr 1983 24-Apr
1991 24-Apr 1966 24-Apr
1990 15-Apr 1962 24-Apr
1989 25-Apr 1942 24-Apr
1988 19-Apr 1939 24-Apr
1987 22-Apr 2012 25-Apr
1986 25-Apr 1995 25-Apr
1985 30-Apr 1989 25-Apr
1984 30-Apr 1986 25-Apr
1983 24-Apr 1953 25-Apr
1982 5-May 2007 26-Apr
1981 23-Apr 1996 26-Apr
1980 26-Apr 1980 26-Apr
1979 28-Apr 2001 27-Apr
1978 28-Apr 1999 27-Apr
1977 23-Apr 1965 27-Apr
1976 2-May 1961 27-Apr
1975 9-May 1952 27-Apr
1974 1-May 1949 27-Apr
1973 23-Apr 1936 27-Apr
1972 5-May 1931 27-Apr
1971 5-May 2006 28-Apr
1970 1-May 2002 28-Apr
1969 4-May 1979 28-Apr
1968 28-Apr 1978 28-Apr
1967 4-May 1968 28-Apr
1966 24-Apr 1951 28-Apr
1965 27-Apr 1946 28-Apr
1964 30-Apr 1943 28-Apr
1963 1-May 1938 28-Apr
1962 24-Apr 1932 28-Apr
1961 27-Apr 1928 28-Apr
1960 29-Apr 1926 28-Apr
1959 29-Apr 1960 29-Apr
1958 30-Apr 1959 29-Apr
1957 30-Apr 1944 29-Apr
1956 1-May 1985 30-Apr
1955 14-May 1984 30-Apr
1954 6-May 1964 30-Apr
1953 25-Apr 1958 30-Apr
1952 27-Apr 1957 30-Apr
1951 28-Apr 1924 30-Apr
1950 10-May 2009 1-May
1949 27-Apr 1974 1-May
1948 12-May 1970 1-May
1947 18-Apr 1963 1-May
1946 28-Apr 1956 1-May
1945 1-May 1945 1-May
1944 29-Apr 1935 1-May
1943 28-Apr 1933 1-May
1942 24-Apr 1927 1-May
1941 18-Apr 1925 1-May
1940 19-Apr 1997 2-May
1939 24-Apr 1976 2-May
1938 28-Apr 1929 2-May
1937 8-May 2008 4-May
1936 27-Apr 1969 4-May
1935 1-May 1967 4-May
1934 11-Apr 1982 5-May
1933 1-May 1972 5-May
1932 28-Apr 1971 5-May
1931 27-Apr 1954 6-May
1930 19-Apr 2011 7-May
1929 2-May 1993 7-May
1928 28-Apr 1937 8-May
1927 1-May 1923 8-May
1926 28-Apr 1975 9-May
1925 1-May 1950 10-May
1924 30-Apr 1948 12-May
1923 8-May 1955 14-May
1922 16-May 1922 16-May

The data in the table was provided from 1922 to 1993 by the various people who worked for the National Weather Service office in Wenatchee, for the fruit growers and public. Since the NWS office was closed in 1993, the date of full bloom has been monitored at the WSU Tree Fruit Research and Extension Center by the Regional Extension Specialist from the Chelan / Douglas County office of WSU Extension. These data are of both significant historical and practical importance, and are used by various individuals to better understand production, harvest and quality of the past crops produced in the region.
Full bloom is defined as the day that 60% of “king blossoms” are open on the north (shady) side of the tree. (The king blossom is the larger dominant blossom that is usually found in the center of the blossom cluster, surrounded by the yet unopened “side blossoms.”) Frosted blossom buds may open with an incomplete or missing king flower.

Red Delicious is a relatively late blossoming apple cultivar, and other apple cultivars on warmer sites in the local region will bloom up to a week earlier. Elevation and slope aspect are quite variable over short distances in this region, and very influential in relation to blossom development rate. Lower elevation orchards (~700 ft. elevation) may see blossoms up to a month before higher elevations (~3,400 ft.) in this region. Apricots bloom first in the region, usually three weeks before Red Delicious growing on similar sites. Then peaches and nectarines bloom, about 14 – 17 before apples, then cherries about 10 – 14 days before apples, then pears about 7 – 10 days prior, then come the apples.

Some Fun Facts:

As of 1925 through 2016, the 91 year average full bloom date in Wenatchee is: April 27

The Average Full Bloom Date From 1995-2005 is: April 23
The Average Full Bloom Date From 1990-1999 is: April 21
1980-89: April 25
1970-79: April 30
1960-69: April 28
1950-59: May 2
1940-49: April 26
1930-39: April 26

Contact

Tianna DuPontImg1380

WSU Extension Specialist, Tree Fruit

tianna.dupont@wsu.edu

(509) 663-8181 ext 211