Degree Days

What are degree days?

Growing degree days (DD) are a weather-based indicator for assessing crop and pest development. It is a calculation used by crop producers that measures heat accumulation used to predict plant and pest development rates. Growing degrees are defined as the mean daily temperature (average of daily maximum and minimum temperatures) above a certain threshold base temperature accumulated on a daily basis over a period of time. Daily growing degree day values are added together from the beginning of the season. Degree day totals are also used for comparing the progress of a growing season to the long-term average.

Degree Day Development Table

The codling moth, like all insects, is cold blooded. Meaning, the temperature around it determines how fast it grows and how active it is as an adult moth. We can take advantage of this to predict what life stage the majority of the codling moths population are in. Scientists have developed a model that uses degreedays to predict codling moth development. These predictions are summarized in this table.

Degree day total
(+/- 3-5 DD)
Codling moth stage of development
100Emergence of 1st brood moths from overwintering larvae
150Beginning of 1st brood egg laying
220Start of 1st egg hatch (first brood larvae)
500End of emergence of 1st brood moths
575Start of emergence of 2nd brood moths
650End of 1st brood egg hatch
700Start of 2nd brood egg hatch (2nd brood larvae)
1140End of 2nd brood moth emergence
1160Start of 3rd brood moth emergence
1275End of 2nd brood egg hatch
1300Start of 3rd brood egg hatch

A complete codling moth degree day development table is also available as a PDF – Full Codling Moth Degree Day Development Table.

More information about the codling moth stages of development, see Codling Moth.

Degree Day Tables

The degree day totals in the table below indicate the predicted stage of development of codling moth populations near specific weather stations located around the valley. Growers and advisors can use the values to determine the life stages of the codling moth in their area. This will help determine the proper time to apply ovicidal and larvicidal products to control each of the codling moth generations if needed.

  • 2017 Degree Days - South
    Weather Station Location
    OsoyoosOliver SouthOliver NorthCawstonKeremeosPentictonSummerland
    June 21442376402386430376334
    June 18412352377364402325304
    June 15397336362348387312291
    June 14384327352339376304283
    June 11357294319308342283263
    June 7336285309306332267245
    June 5309259281272305244221
    June 1274229249241271216193
    May 29223187206195222186161
    May 25203161179166191154128
    May 23187148165151175140114
    May 1814710712210512810681
    May 15139991149811810075
    May 7106708270877956
    April 3067455446625034
    April 1835233025372814
    Data from Osoyoos, Penticton and Summerland comes from Environment Canada.
    Data from Oliver south, Oliver north, Cawston, and Keremeos comes from Growers Supply's weather network.
  • 2017 Degree Days - Central
    Weather Station Location
    WestbankKelowna SouthKelowna EastBenvoulinBelgoGlenmoreEllison
    June 21371349365341341333338
    June 18346324342319316309313
    June 15330311329306302295299
    June 14318301318297293286289
    June 11286267285266260255257
    June 7275257276257252246247
    June 5245230247233224221221
    June 1216242260207195193193
    May 29171197213167149151150
    May 25142171185142123126125
    May 23130131132130112115114
    May 1889769091737878
    May 1575688081657070
    May 758475758454951
    April 3038324020303336
    April 1821162141141620
    Data from Westbank, Kelowna South, Kelowna East, Belgo, Glenmore and Ellison comes from Growers Supply's weather network.
  • 2017 Degree Days - North
    Weather Station
    Winfield NorthWinfield SouthOK Landing & Bella VistaVernon North & BX Salmon Arm
    June 21313311346367324
    June 18291288320330300
    June 15278276308301287
    June 14268266297281278
    June 11237237236248264
    June 7228228253239238
    June 5203202224211214
    June 1176173195183188
    May 29134130149138157
    May 25110104123111128
    May 239893112101116
    May 186356736383
    May 155650665777
    May 73834463856
    April 302522312438
    April 18119141017
    Data from Salmon Arm comes from Environment Canada.
    Data from Oyama, Winfield South, OK Landing & Bella Vista, and Vernon North & BX comes from Growers Supply's weather network.