Deconstruct SunHardiness Zone 1b: Temperature, States & Cities
In USDA zone 1b, the coldest night of a typical winter falls between −55 and −50 °F (−48.3 to −45.6 °C).
average annual extreme minimum
Where is zone 1b?
On the 2023 USDA map, zone 1b appears in Alaska.
Gardening in zone 1b
Pick perennials, shrubs and trees labeled for zone 1b or a lower number. Then match the light: every plant tag also lists full sun, part sun or shade, and that depends on the exact spot, not the zone.
Check your zone
Zone checked. Now measure the sun.
Deconstruct Sun shows how many hours of direct sun one exact spot gets, today and in every season. Free on iPhone.
Questions
What is the temperature range for zone 1b?
In zone 1b, the average coldest winter night is −55 to −50 °F (−48.3 to −45.6 °C). That is the average of each year’s lowest temperature from 1991 to 2020.
What is the difference between zone 1b and 1a?
Both are part of zone 1. The “a” half is 5 °F colder than the “b” half. Zone 1a averages −60 to −55 °F and zone 1b averages −55 to −50 °F.
Can I grow zone 2a plants in zone 1b?
A plant rated for a warmer zone may survive a mild winter, but one hard freeze can kill it. Choose plants rated for your zone or colder for permanent plantings, and treat warmer-zone plants as annuals or grow them in pots you can move.
This is not the official USDA Plant Hardiness Zone Map. Zones are derived from the official 2023 dataset, resampled to about 2 km.