What plant hardiness zone is Ontario

Ontario is located at Malheur County, Oregon (OR), USA.

Plant hardiness zone (winter frost zone or gardening zone) for Ontario 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.

Ontario, Oregon @ wikipedia.