What plant hardiness zone is Thornton

Thornton is located at Whitman County, Washington (WA), USA.

Plant hardiness zone (winter frost zone or gardening zone) for Thornton is 6b by the USDA scale.

Coldest zone's winter temperature is −5 … 0 °F.

Plants of 6b USDA hardiness zone suitable for outdoor gardening and growing in this winter frost zone 6b USDA.

Thornton, Washington @ wikipedia.