1922 to Present at the WSU Tree Fruit Research & Extension Center Wenatchee, WA
Tianna DuPont, WSU Extension; from Tim Smith WSU Extension emeritus.
As of May 1 DD in Wenatchee are 957, predicted first bloom actual full bloom (sentinel Red Delicious). This is -199 DD behind average (22 year) and – 141 DD behind last year.
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 102 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 full bloom date for 2017 was May 1. The full bloom date for 2018 was April 28. 2020 full bloom was on April 17 and in 2019 on April 26.
Daily high temperatures are used to predict bloom based on degree days (DD) above 43℉. Daily DD are equal to daily high – 43℉.
920 DD predict first bloom. 250 predicts late dormancy, 331 silver tip, 440 green tip. As always look at the trees. Models are never perfect.
For more accurate predictions for multiple varieties take a look at the new Decision Aid System model for bloom at https://decisionaid.systems/
Red Delicious Apple Historical Full Bloom recorded in Wenatchee, WA
| Bloom by Year | Date (Bloom by Year) | Earliest to Latest | Date (Earliest to Latest) |
|---|---|---|---|
| 2022 | April 28 | 2016 | April 9 |
| 2021 | April 19 | 2015 | April 9 |
| 2020 | April 17 | 1934 | April 11 |
| 2019 | April 26 | 2004 | April 13 |
| 2020 | April 18 | 1992 | April 14 |
| 2018 | April 28 | 1990 | April 15 |
| 2017 | May 1 | 1994 | April 16 |
| 2016 | April 9 | 1947 | April 18 |
| 2015 | April 9 | 1941 | April 18 |
| 2014 | April 21 | 2000 | April 19 |
| 2013 | April 20 | 1988 | April 19 |
| 2012 | April 25 | 1940 | April 19 |
| 2011 | May 7 | 1930 | April 19 |
| 2010 | April 23 | 2013 | April 20 |
| 2009 | May 1 | 2014 | April 21 |
| 2008 | May 4 | 2005 | April 22 |
| 2007 | April 26 | 2003 | April 22 |
| 2006 | April 28 | 1998 | April 22 |
| 2005 | April 22 | 1987 | April 22 |
| 2004 | April 13 | 2010 | April 23 |
| 2003 | April 22 | 1981 | April 23 |
| 2002 | April 28 | 1977 | April 23 |
| 2001 | April 27 | 1973 | April 23 |
| 2000 | April 19 | 1991 | April 24 |
| 1999 | April 27 | 1983 | April 24 |
| 1998 | April 22 | 1966 | April 24 |
| 1997 | May 2 | 1962 | April 24 |
| 1996 | April 26 | 1942 | April 24 |
| 1995 | April 25 | 1939 | April 24 |
| 1994 | April 16 | 2012 | April 25 |
| 1993 | May 7 | 1995 | April 25 |
| 1992 | April 14 | 1989 | April 25 |
| 1991 | April 24 | 1986 | April 25 |
| 1990 | April 15 | 1953 | April 25 |
| 1989 | April 25 | 2007 | April 26 |
| 1988 | April 19 | 1996 | April 26 |
| 1987 | April 22 | 1980 | April 26 |
| 1986 | April 25 | 2001 | April 27 |
| 1985 | April 30 | 1999 | April 27 |
| 1984 | April 30 | 1965 | April 27 |
| 1983 | April 24 | 1961 | April 27 |
| 1982 | May 5 | 1952 | April 27 |
| 1981 | April 23 | 1949 | April 27 |
| 1980 | April 26 | 1936 | April 27 |
| 1979 | April 28 | 1931 | April 27 |
| 1978 | April 28 | 2006 | April 28 |
| 1977 | April 23 | 2002 | April 28 |
| 1976 | May 2 | 1979 | April 28 |
| 1975 | May 9 | 1978 | April 28 |
| 1974 | May 1 | 1968 | April 28 |
| 1973 | April 23 | 1951 | April 28 |
| 1972 | May 5 | 1946 | April 28 |
| 1971 | May 5 | 1943 | April 28 |
| 1970 | May 1 | 1938 | April 28 |
| 1969 | May 4 | 1932 | April 28 |
| 1968 | April 28 | 1928 | April 28 |
| 1967 | May 4 | 1926 | April 28 |
| 1966 | April 24 | 2018 | April 28 |
| 1965 | April 27 | 1960 | April 29 |
| 1964 | April 30 | 1959 | April 29 |
| 1963 | May 1 | 1944 | April 29 |
| 1962 | April 24 | 1985 | April 30 |
| 1961 | April 27 | 1984 | April 30 |
| 1960 | April 29 | 1964 | April 30 |
| 1959 | April 29 | 1958 | April 30 |
| 1958 | April 30 | 1957 | April 30 |
| 1957 | April 30 | 1924 | April 30 |
| 1956 | May 1 | 2009 | May 1 |
| 1955 | May 14 | 1974 | May 1 |
| 1954 | May 6 | 1970 | May 1 |
| 1953 | April 25 | 1963 | May 1 |
| 1952 | April 27 | 1956 | May 1 |
| 1951 | April 28 | 1945 | May 1 |
| 1950 | May 10 | 1935 | May 1 |
| 1949 | April 27 | 1933 | May 1 |
| 1948 | May 12 | 1927 | May 1 |
| 1947 | April 18 | 1925 | May 1 |
| 1946 | April 28 | 2017 | May 1 |
| 1945 | May 1 | 1997 | May 2 |
| 1944 | April 29 | 1976 | May 2 |
| 1943 | April 28 | 1929 | May 2 |
| 1942 | April 24 | 2008 | May 4 |
| 1941 | April 18 | 1969 | May 4 |
| 1940 | April 19 | 1967 | May 4 |
| 1939 | April 24 | 1982 | May 5 |
| 1938 | April 28 | 1972 | May 5 |
| 1937 | May 8 | 1971 | May 5 |
| 1936 | April 27 | 1954 | May 6 |
| 1935 | May 1 | 2011 | May 7 |
| 1934 | April 11 | 1993 | May 7 |
| 1933 | May 1 | 1937 | May 8 |
| 1932 | April 28 | 1923 | May 8 |
| 1931 | April 27 | 1975 | May 9 |
| 1930 | April 19 | 1950 | May 10 |
| 1929 | May 2 | 1948 | May 12 |
| 1928 | April 28 | 1955 | May 14 |
| 1927 | May 1 | 1922 | May 16 |
| 1926 | April 28 | 2020 | April 17 |
| 1925 | May 1 | 2020 | April 18 |
| 1924 | April 30 | 2019 | April 26 |
| 1923 | May 8 | 2021 | April 19 |
| 1922 | May 16 | 2022 | April 28 |
| April 27 |
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 2018, the 93 year average full bloom date in Wenatchee is: May 4.
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 DuPont
WSU Extension Specialist, Tree Fruit
tianna.dupont@wsu.edu
(509) 293-8758
