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
    September 141527135614021493157613041374
    September 111502133313781467154712821349
    September 81469130113461436151212511316
    September 61448127213171406147912311294
    September 11385122412701349142011821238
    August 301373120912561336140511611213
    August 281338117712231294136311291175
    August 251306114911961266133411041149
    August 231279112311691236130410791120
    August 211255110211491212127810601101
    August 181214106711151173123510251063
    August 161190104610941149121010041042
    August 14116510231071112611879821018
    August 111139998104710941154956989
    August 7108793798710161076912911
    August 310329009489691029857879
    August 110008749209381013829865
    July 30967843889907967804822
    July 27921802846862922765781
    July 26907769811824882752766
    July 23866746786798853717730
    July 21828721762773827686695
    July 19804698738746800664671
    July 17778678717726778644650
    July 13737642679683734604607
    July 11708616653657707579580
    July 9676541575575621552550
    July 6630498532525572510503
    July 3604486519510557487478
    June 29534459492479525428414
    June 27507437466455498408390
    June 25479411439427472381361
    June 22450384410394440355334
    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
    September 141387139313731123137912421286
    September 111362136513471104135212201261
    September 81333133213161079131911911230
    September 61300129612841054128211611195
    September 11248124012271015122511121143
    August 301236122812151006121211011132
    August 28120311901181980117210681097
    August 25118011661156962114810461074
    August 23115211371130941112010201047
    August 21113211181109926110110031031
    August 181093108110728991066970996
    August 161072106110508841046951978
    August 141050103910288681026932958
    August 11102110111003847997907932
    August 7960944939798928853873
    August 3920902899769885820835
    August 1906887885758871807823
    July 30863845845729828773455
    July 27818800803695785732748
    July 26784765768670752702718
    July 23761743746652732697672
    July 21737716722631706659673
    July 19713692697612681639649
    July 17693672678597663622633
    July 13650631636565621586595
    July 11623603610543594562569
    July 9548523534480515489494
    July 6502477490445468447453
    July 3488463476434454435440
    June 29455432446410424406412
    June 27435411427392404388394
    June 25408383399369374362366
    June 22378355371346348338343
    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
    Location
    Winfield NorthWinfield SouthOK Landing & Bella VistaVernon North & BX Salmon Arm
    September 1412461297136213951179
    September 1112221273133413721154
    September 811941243130313451127
    September 611641207126813131109
    September 111131153121112611062
    August 3011021141119912511040
    August 2810681102115912141008
    August 251046108011371194987
    August 231018105211091167964
    August 211001103510891150949
    August 18968100110541119920
    August 1695098210341101906
    August 1493396310151085888
    August 119079349851057865
    August 7850870923903822
    August 3812829878858776
    August 1799816864838819
    July 30763775823815728
    July 27723732780773694
    July 26693700747761683
    July 23672679728654
    July 21648656705626
    July 19627633681675608
    July 17610615664748591
    July 13572574622707556
    July 11548549595683532
    July 9475475517596510
    July 6433431472550472
    July 3420418458534451
    June 29391388428499394
    June 27372369407468377
    June 25345341379433351
    June 22320316353382329
    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.