Data: 2023 USDA zones (PRISM/OSU) · NOAA 1991–2020 normals · updated

Zone 5a

In USDA zone 5a the coldest night of an average winter reaches −20 to −15 °F (−28.9 to −26.1 °C). 2,426 ZIP codes (6.0% of all) are in this zone.

Zone5a−20 to −15 °F
Coldest night−28.9 to −26.1 °C
ZIP codes2,426
Typical last frostMay 3
Typical first frostOct 5

Frost dates vary within zone 5a

For the middle half of zone-5a ZIP codes the last spring frost falls between Apr 30 and May 13, and the first fall frost between Oct 1 and Oct 10. The zone measures winter cold, not season length: humid Eastern and dry Western towns in the same zone can be weeks apart. Use your ZIP code for a planting date.

States with zone 5a

Iowa563 ZIPsMinnesota271 ZIPsWisconsin250 ZIPsVermont176 ZIPsSouth Dakota168 ZIPsMaine151 ZIPsNew York141 ZIPsMichigan132 ZIPsNebraska112 ZIPsMontana111 ZIPsWyoming111 ZIPsColorado73 ZIPsNew Hampshire59 ZIPsIdaho40 ZIPsAlaska33 ZIPs

Cities mostly in zone 5a

Minneapolis, MN66 ZIPsSaint Paul, MN36 ZIPsAnchorage, AK25 ZIPsCedar Rapids, IA14 ZIPsSioux Falls, SD14 ZIPsBillings, MT14 ZIPsSioux City, IA9 ZIPsDubuque, IA5 ZIPsBozeman, MT5 ZIPsCasper, WY5 ZIPsBurlington, VT5 ZIPsKincheloe, MI4 ZIPs

← Zone 4b (colder)Zone 5b (warmer) →

Questions

What is the temperature range of zone 5a?

Zone 5a covers places where the coldest night of an average winter (the annual extreme minimum averaged over 1991–2020) is −20 to −15 °F, or −28.9 to −26.1 °C.

When is the last frost in zone 5a?

Across ZIP codes in zone 5a, the median last spring frost falls between Apr 30 and May 13 for the middle half of places. Zone alone doesn't set the frost date — check your ZIP code.

Which states have zone 5a?

Zone 5a occurs in 19 states; the most ZIP codes are in Iowa, Minnesota, Wisconsin, Vermont, South Dakota.

What can I grow in zone 5a?

Perennials, shrubs and trees labeled hardy to zone 5a or a lower (colder) number should survive a typical winter. Annual vegetables depend on frost dates rather than zone.

Not the official USDA Plant Hardiness Zone Map. Zones come from the 2023 USDA hardiness-zone data by the PRISM Group, Oregon State University; we re-mapped and recolored them. The official map is at planthardiness.ars.usda.gov.