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 degree–days 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.

  • 2021 Degree Days - South
    Weather StationOsoyoosOliver South Oliver CentralCawstonKeremeosPenticton AirportSummerland North
    September 20, 20211666159916321665169614501358
    September 15, 20211641157516071643167314291341
    September 13, 20211627156415941632166214201335
    September 10, 20211601154115701611163913991315
    September 8, 20211585152515521591161313851297
    September 7, 20211574151415411580160213751288
    September 1, 20211518146114821522154213311241
    August 30, 20211505145114711511152813181233
    August 27, 20211474142014421477149312891206
    August 25, 20211460140314241460147712781194
    August 23, 20211441138714071441145812631180
    August 20, 20211419137613871418143612411165
    August 16, 20211372132813451376139612071131
    August 12, 20211316127612891311133211471083
    August 10, 20211288124512571277129811211053
    August 5, 2021122011901199122012411060897
    July 30, 202111291102110711221142975922
    July 28, 202110941072107610861107946895
    July 26, 202110601041104510551075914869
    July 23, 2021101799799710091028877832
    July 21, 20219869739709871003853811
    July 19, 2021963948945962979827788
    July 16, 2021910905898916932785745
    July 12, 2021845843834853869726686
    July 9, 2021797793784802819682641
    July 7, 2021768771759775791654617
    July 6, 2021754757744762778640607
    June 23, 2021525539527539555422407
    June 22, 2021511525512524540409394
    June 11, 2021400411400409423314298
    June 9, 2021390400388400414308291
    June 7, 2021382388376389404301282
    June 4, 2021353375360376388276269
    June 2, 2021326351334349362255248
    May 28, 2021275292276290303211198
    May 26, 2021260279262278288201189
    May 25, 2021250269253269281193182
    May 21, 2021232243226242252174159
    May 17, 2021210226211228237155149
    May 14, 2021184198185195204132128
    May 12, 2021173185174180189123117
    May 10, 2021164176166172182117111
    April 30, 20211101201131171258077
    April 26, 202196105991021116866

  • 2021 Degree Days - Central
    Weather StationWest KelownaKelowna SouthKelowna EastBenvoulinBelgoGlenmoreEllison
    September 20, 20211488150614851265148014211396
    September 15, 20211470148914681253146414081381
    September 13, 20211462148114601249145614031375
    September 10, 20211439145714371230143313821351
    September 8, 20211420144114211219141613671337
    September 7, 20211411143114101212140513571327
    September 1, 20211363138213611175135513141283
    August 30, 20211354137313531170134613081277
    August 27, 20211327134513241149131612811249
    August 25, 20211312132813081138130112651236
    August 23, 20211297131312921125128612501222
    August 20, 20211272128012711110126712301204
    August 16, 20211235125412381081123111971171
    August 12, 20211180120111901046117511501124
    August 10, 20211147117111591018114611201095
    August 5, 2021108911141107973109010661038
    July 30, 2021100410271022902999986959
    July 28, 2021973996991879967958931
    July 26, 2021944967964858938930906
    July 23, 2021898921919824892886864
    July 21, 2021876898897805872864841
    July 19, 2021852872874787848842819
    July 16, 2021806826830749805799777
    July 12, 2021744764771700743742721
    July 9, 2021697715726659696697678
    July 7, 2021672690701637671673654
    July 6, 2021659677688626658661642
    June 23, 2021438455477429440453436
    June 22, 2021422439461416425438422
    June 11, 2021317331353321319331320
    June 9, 2021308321344313312322311
    June 7, 2021299311332303302311301
    June 4, 2021283298317292291297283
    June 2, 2021262275297275269275266
    May 28, 2021210222242229216226218
    May 26, 20211992122312191207216207
    May 25, 2021190204221211197207199
    May 21, 2021163176192186171180173
    May 17, 2021153164179174160169162
    May 14, 2021127138150151133144137
    May 12, 2021117127139141122133127
    May 10, 2021111120130133115125121
    April 30, 202178849095828985
    April 26, 202165717680707571

  • 2021 Degree Days - North
    Weather StationWinfield NorthWinfield SouthBella VistaVernon North & BXSalmon Arm
    September 20, 202113981378152814621214
    September 15, 202113831365151214471202
    September 13, 202113771360150614391192
    September 10, 202113541337147914141174
    September 8, 202113401322146113971162
    September 7, 202113301312145013861153
    September 1, 202112871268139913391118
    August 30, 202112821263139113331112
    August 27, 202112561237136013041093
    August 25, 202112431225134312891083
    August 23, 202112281211132712741073
    August 20, 202112081194130512541051
    August 16, 202111731159126712191019
    August 12, 20211126110812091163976
    August 10, 20211097108011801135953
    August 5, 20211043102711241083897
    July 30, 20219619421036996829
    July 28, 20219329131005965805
    July 26, 2021906884974936778
    July 23, 2021865841931891750
    July 21, 2021842820912869729
    July 19, 2021820 797887847707
    July 16, 2021776755841804669
    July 12, 2021719698778744618
    July 9, 2021672651729698577
    July 7, 2021648626703672552
    July 6, 2021635613689658539
    June 23, 2021423401467444349
    June 22, 2021410386451429339
    June 11, 2021309288338325257
    June 9, 2021300279327314250
    June 7, 2021288269313303242
    June 4, 2021274256298291225
    June 2, 2021252234274268206
    May 28, 2021204186221217170
    May 26, 2021193178210208163
    May 25, 2021184169199198154
    May 21, 2021159144173173139
    May 17, 2021148134160161123
    May 14, 2021123111132135107
    May 12, 202111310312112499
    May 10, 20211069711411795
    April 30, 20217368798365
    April 26, 20215956667053

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