Growing Degree Days

Growing Degree Day (GDD) models help predict when frost tolerance is approaching. The GDD numbers above are indicated for State Bog, East Wareham and the GDD numbers at your location may be a little different depending on where you are in the state. The CCCGA Frost Committee uses the GDD models as a tool but also relies on traditional visual observation. The models are still being evaluated as they work better in some years than others. Don’t rely on these exclusively. They should only be used as another guide in understanding how the season is progressing, helping growers make more informed frost decisions. Below are key models being used:

Irving DeMoranville (Dee) model

  • 44°F base temperature; accumulate starting from Jan 1. When 100 GDD is reached, be extra vigilant for frost and white bud stage is expected

University of WI models – accumulate starting from 13-hour day (starts on April 7)

  • WI Simple model: 41°F base temperature. When 90-100 GDD is reached, be extra vigilant for frost and dormant phase should have ended.
  • WI Complex model: Temperatures between 41°F and 86°F; if minimum or maximum is >41°F, set to 41°F. When 90-100 GDD is reached, be extra vigilant for frost and dormant phase should have ended.

The GDD numbers at State Bog (East Wareham, MA)

Growing Degree Days 5/12/25

The GDD numbers at State Bog (East Wareham, MA) through May 11 are as follows:

Dee model (base 44℉ and Jan 1): 356.4

WI simple (base 41℉ and April 7): 397.7

WI complex (base 41℉, max 86℉ and April 7): 426.0

Growing Degree Days 5/7/25

The GDD numbers at State Bog (East Wareham, MA) through May 7 are as follows:

Dee model (base 44℉ and Jan 1): 296.4

WI simple (base 41℉ and April 7): 325.7

WI complex (base 41℉, max 86℉ and April 7): 354.0

Growing Degree Days 5/5/25

The GDD numbers at State Bog (East Wareham, MA) through May 4 are as follows:

Dee model (base 44℉ and Jan 1): 243.7

WI simple (base 41℉ and April 7): 264.0

WI complex (base 41℉, max 86℉ and April 7): 292.3

Growing Degree Days 5/1/25

The GDD numbers at State Bog (East Wareham, MA) through April 30 are as follows:

Dee model (base 44℉ and Jan 1): 193.2

WI simple (base 41℉ and April 7): 201.4

WI complex (base 41℉, max 86℉ and April 7): 227.4

Growing Degree Days 4/28/25

The GDD numbers at State Bog (East Wareham, MA) through April 27 are as follows:

Dee model (base 44℉ and Jan 1): 152.2

WI simple (base 41℉ and April 7): 151.4

WI complex (base 41℉, max 86℉ and April 7): 176.6

Growing Degree Days 4/24/25

The GDD numbers at State Bog (East Wareham, MA) through April 23 are as follows:

Dee model (base 44℉ and Jan 1): 107.4

WI simple (base 41℉ and April 7): 94.6

WI complex (base 41℉, max 86℉ and April 7): 118.9

Growing Degree Days 4/22/25

The GDD numbers at State Bog (East Wareham, MA) through April 20 are as follows:

Dee model (base 44℉ and Jan 1): 84.8

WI simple (base 41℉ and April 7): 63.1

WI complex (base 41℉, max 86℉ and April 7): 84.6

Growing Degree Days 4/17/25

The GDD numbers at State Bog (East Wareham, MA) through April 16 are as follows:

Dee model (base 44℉ and Jan 1): 59.2

WI simple (base 41℉ and April 7): 25.6

WI complex (base 41℉, max 86℉ and April 7): 42.2

Growing Degree Days 4/14/25

The GDD numbers at State Bog (East Wareham, MA) through April 13 are as follows:

Dee model (base 44℉ and Jan 1): 45.6

WI simple (base 41℉ and April 7): 3.0

WI complex (base 41℉, max 86℉ and April 7): 15.4

Growing Degree Days 4/8/2025

The GDD numbers at State Bog (East Wareham, MA) through 4/7/25 are as follows:

  • Dee model (base 44℉ and Jan 1): 45.6
  • WI simple (base 41℉ and April 7): 2
  • WI complex (base 41℉, max 86℉ and April 7): 3.4

Growing Degree Days 4/3/2025

The GDD numbers at State Bog (East Wareham, MA) through 4/1/25 are as follows:

  • Dee model (base 44℉ and Jan 1): 30.4
  • WI simple (base 41℉ and April 7): 0
  • WI complex (base 41℉, max 86℉ and April 7): 0

Growing Degree Days 3/27/2025

The GDD numbers at State Bog (East Wareham, MA) till 03/26 are as follows:

  • Dee model (base 44℉ and Jan 1): 26.1
  • WI simple (base 41℉ and April 7): 0
  • WI complex (base 41℉, max 86℉ and April 7): 0