Please Note

The GDD models have only been “ground-truthed” in the Great Lakes region. Use of models outside of this region, including the North East, Great Plains and Transition Zones, should be used with caution. We do not recommend the GDD models we use for the mid/southern transition zone and southern states.


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Tabular Data

Dollar Spot Probability Details

DateAir Temp (F)
5 day avg.
Rel. Humidity
5 day avg.
DS Probability
2021-06-12 79° 70 46.9%
2021-06-11 78° 73 51.2%
2021-06-10 76° 75 51.6%
2021-06-09 75° 74 45.7%
2021-06-08 74° 71 36.8%
2021-06-07 73° 68 28.8%
2021-06-06 71° 67 23.1%


Latest Updates

February 19th, 2021Welcome to the 2021 GDD Tracking Season

Despite the frigid temperatures covering most of the country this week, GDDtracker started counting on February 15. As temperatures warm and snow fall melts the first two models that gather the most attention are the Proxy/Primo timer for scheduling annual bluegrass seedhead suppression applications and the crabgrass preemergence application timer. As the season progresses the early season DMI timer and the Smith-Kerns dollar spot prediction model gather views. Further information on all models can be found under the "About" tab at the top of the screen. Thanks for your continued use and support of GDDtracker and best wishes for a successful 2021 growing season!