Zone change in 15 years

[swincher]

Yes, but just be warned that this topic tends to result in politically motivated arguments that may end up with a locked thread. That being said, here’s the thread I started awhile ago for Seattle:

Seattle should be moving to zone 9a in the next update

In the USDA map based on data as of 1990, Seattle was placed in zone 8a, meaning the 30-year average of the annual minimum temperature was 10-15°F at that point. The latest USDA growing zone maps were based on 2012 data, when Seattle’s number was in the upper teens and we were moved to zone 8b. Well I don’t know when the USDA will be updating their maps next, but at least for the official Seattle weather station, our 30-year average is now 21.2°F, which would put us in 9a if the map was re-dra…