NOAA's Interactive Maps Show How Your Climate Is Changing
The maps are based off of the official U.S. Climate Normal, which are updated every 10 years and last updated in 2010. By averaging the coldest days each year for the 30-year window and sorting those averages into 10-degree Fahrenheit "planting zone" bins, they were able to make a continuous map with similar minimum temperatures between the two time periods.
This map shows the planting zones between 1971 and 2000.
This map shows the planting zones between 1981 and 2010.
As a whole it may not look like much has changed. But, when you zoom in on your region, you'll see that those slight changes made a huge difference. The 1970s was an unusually cool decade, while the 10 year period between 2001 and 2010 was the warmest ever recorded, causing for drastic shifts. For this reason, according to NOAA, planting zones have shifted northward and upward in elevation in many parts of the country, because warming winter nights are allowing plants to migrate. This is evident in the third map, which shows shifts in planting zones:
By basing it off of winter averages, we know that plants that used to survive in the region, may no longer make it in these changing times. Some plants need a long enough winter to go into dormancy and return in the spring to flower while other plants can't survive at all in sub-freezing temperatures. Climate.gov said these changes are also causing longer and more severe wildfire seasons, and allowing pests to thrive and spread to what used to be colder regions. Overall, this could be having adverse effects on pollination patterns, the food chain and ultimately the biodiversity of any given region.
"Species, including many iconic species, may disappear from regions where they have been prevalent or become extinct, altering some regions so much that their mix of plant and animal life will become almost unrecognizable," reported the Third National Climate Assessment in 2014.
These new "climate normals" can help people know exactly what to plant to ensure their garden is a healthy environment for native species.