What plant hardiness zone is Altona

Altona is located at Boulder County, Colorado (CO), USA.

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

Coldest zone's winter temperature is −10 … -5 °F.

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