If you’re an avid gardener who pursues your passion all year round, you may be familiar with a handy guide commonly found at nurseries that tells you if the azaleas, rhododendrons, or other perennials you’re thinking of planting in your garden are likely to survive the winter. The Plant Hardiness Zone Map is divided into 13 temperature zones and half-zones, stretching from frigid Alaska (1a) to tropical Puerto Rico (13b), and is based on a 30-year average of the coldest winter temperatures recorded for each zone. 

Earlier this month, the USDA released the latest version of the interactive map which was co-developed by researchers at the PRISM Climate Group at Oregon State University. An update to the 2012 map, the new version shows an average nationwide shift of 2.5 degrees Fahrenheit, which may indicate warming temperatures due to climate change, among other factors. Chris Daly is the lead author of the new map, the founding director of the PRISM Climate Group and  a professor in the college of engineering at Oregon State University. He joins us to talk about developing the map, what it means for Oregon growers and the impact of a changing climate on the winter growing season.