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

Zone 5b

In USDA zone 5b the coldest night of an average winter reaches −15 to −10 °F (−26.1 to −23.3 °C). 2,880 ZIP codes (7.1% of all) are in this zone.

Zone5b−15 to −10 °F
Coldest night−26.1 to −23.3 °C
ZIP codes2,880
Typical last frostMay 1
Typical first frostOct 10

Frost dates vary within zone 5b

For the middle half of zone-5b ZIP codes the last spring frost falls between Apr 25 and May 10, and the first fall frost between Oct 4 and Oct 16. 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 5b

Illinois447 ZIPsNew York436 ZIPsIowa433 ZIPsNebraska291 ZIPsWisconsin263 ZIPsColorado217 ZIPsMaine150 ZIPsMichigan108 ZIPsNew Hampshire85 ZIPsPennsylvania68 ZIPsMassachusetts56 ZIPsVermont46 ZIPsIndiana45 ZIPsIdaho44 ZIPsMissouri39 ZIPs

Cities mostly in zone 5b

Des Moines, IA57 ZIPsMadison, WI32 ZIPsRockford, IL14 ZIPsGreen Bay, WI12 ZIPsAurora, IL10 ZIPsDavenport, IA9 ZIPsMissoula, MT8 ZIPsFort Collins, CO8 ZIPsPalatine, IL7 ZIPsSchaumburg, IL7 ZIPsCheyenne, WY7 ZIPsIdaho Falls, ID7 ZIPs

← Zone 5a (colder)Zone 6a (warmer) →

Questions

What is the temperature range of zone 5b?

Zone 5b covers places where the coldest night of an average winter (the annual extreme minimum averaged over 1991–2020) is −15 to −10 °F, or −26.1 to −23.3 °C.

When is the last frost in zone 5b?

Across ZIP codes in zone 5b, the median last spring frost falls between Apr 25 and May 10 for the middle half of places. Zone alone doesn't set the frost date — check your ZIP code.

Which states have zone 5b?

Zone 5b occurs in 26 states; the most ZIP codes are in Illinois, New York, Iowa, Nebraska, Wisconsin.

What can I grow in zone 5b?

Perennials, shrubs and trees labeled hardy to zone 5b 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.