If the map appears inaccurate, you may be in a microclimate.
Some zip codes are in small areas that are warmer or cooler than the surrounding area. These areas, called microclimates, are often associated with urbanization or steep elevation changes, and many are too small to show on our map.
If it looks on the map like your zip code should be in a different hardiness zone than the one we provide for you, your zip code is probably in a microclimate that is too small to represent on the map.
A good example of this is Chicago, Illinois. Several zip codes for the city of Chicago bring up zones 5-6.
Microclimates occur in most large cities due to the urbanization effect that buildings bring about. In addition, regions of the country with bodies of water or mountains may contain “pockets.” These climatic pockets mirror warmer or cooler zones than the surrounding region.
What are Hardiness Zones?

The USDA hardiness zones divide the United States into 13 areas to help tree planters, gardeners, and farmers understand which plants are most likely to thrive in their location. These zones are based on the region’s lowest average annual temperature, meaning a plant suited for a particular zone can be expected to grow in that region’s temperature extremes.

Zones get warmer as their numbers rise, with Zone 1 being the coldest and Zone 13 being the warmest. They are divided into increments of 10° Fahrenheit.

Keep in mind that local variations like moisture, soil, wind, and other conditions also affect a plant’s ability to thrive, so if you have questions, you may want to consult with a local professional arborist or nursery about what plants are right for your area.

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