Insects are ectothermic, meaning that their development is governed largely by ambient temperatures. Land managers can take advantage of this phenomenon by using predictive models that correlate heat units, or degree-days, with insect life stages. In this way, management efforts can be more focused in particular time periods. For more information on how these heat units are calculated, visit http://ipm.ucanr.edu/WEATHER/index.html.
The map below shows the degree-day accumulation for insects with developmental thresholds between 50 and 86 degrees Farenheit as of December 15, 2016 in Wisconsin, USA. The data used in these calculations was collected from https://www.wunderground.com/history/, 46 weather stations from across WI. It should be noted that at this time of year, most insects in WI are hibernating, or in diapause.