About the Freeze Date Tool:


The Freeze Date Tool is a product created by the Midwestern Regional Climate Center (MRCC) in collaboration with the USDA Midwest Climate Hub to provide information about the climatology of freezing temperature dates across the north-central and northeastern United States. This tool can be used to answer questions such as:


All trends in the Freeze Date Tool use a simple linear regression to define the trend in the data over time. The magnitude of the trend is the slope of the linear regression function. The statistical significance of the trend is based on whether the slope of the linear regression is statistically-significantly non-zero (based on a 95% confidence interval). Because trends in climatological data are not necessarily linear, these trends should be interpreted with caution.


The Freeze Date Tool uses the Northeast Regional Climate Center's interpolated dataset from the Applied Climate Information System (ACIS) to obtain spatially continuous daily surface minimum temperature observations. These observations were spatially aggregated by taking the average of all daily surface minimum temperature observations within each county to obtain a single minimum temperature observation for each county. Please be aware that local freeze conditions may differ from the county averages used in this tool due to influences from topography and data availability.

The growing season is defined by the longest period of continuous above-freezing temperatures in a given year. Similarly, the last spring freeze and first fall freeze are the freezes that occur immediately preceding or following that same period of continuous above-freezing temperatures respectively.