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USDA 2023 hardiness zone · NOAA 1991–2020 frost dates

Frost dates in USDA zone 6b (-5 to 0°F)

USDA zone 6b covers places whose coldest winter night averages -5 to 0°F. Across the 736 NOAA weather stations in zone 6b, the median last spring frost is Apr 24, but it ranges from Apr 10 to May 16 for most stations. Enter your ZIP for your local date.

  • Apr 24Median last spring frostmost stations Apr 10–May 16
  • Oct 20Median first fall frost50% chance of 32°F by this date
  • 178 daysMedian growing seasonbetween 32°F freezes
  • 5,271ZIP codes in zone 6b-5 to 0°F average coldest night
  • 736Stations with frost datesof 749 NOAA stations matched

Your ZIP code’s zone and frost dates

Your ZIP gives your zone and the closest NOAA station, which is a better guide than the zone-wide numbers.

5 digits, for example 20001.

From your seed packet, e.g. “start 6 weeks before last frost”.

Earliest and latest last-frost stations in zone 6b

Earliest median last spring frost, zone 6b
StationLast spring frostFirst fall frost
Ash Mountain, CAMar 12Dec 9
Lakeside, MOMar 31Nov 3
Mount Carmel, ILApr 2Oct 31
Brownstown 4 SW, ILApr 3Oct 24
Albion, ILApr 4Oct 28
Benton 2 N, ILApr 4Oct 28
Clarksville L&d 24, MOApr 4Nov 1
Kansas City Downtown Airport, MOApr 4Nov 2
Saverton L&d 22, MOApr 4Nov 4
Springfield Wbo, MOApr 4Oct 27
Latest median last spring frost, zone 6b
StationLast spring frostFirst fall frost
Wolf Canyon, NMJun 19Sep 13
Idaho City, IDJun 17Sep 5
Sunset Crater National Monument, AZJun 16Sep 19
Alpine, AZJun 15Sep 21
Jess Valley, CAJun 14Sep 18
Ibapah, UTJun 14Sep 8
Rome 2 NW, ORJun 11Sep 10
Portola, CAJun 11Sep 10
Redmond Roberts Field, ORJun 9Sep 14
Klamath Falls Intl Airport, ORJun 9Sep 18

Zone 6b by state

Zone 6b stations by state
StateStationsMedian last frostMedian first frost
Alaska5May 11Oct 1
Arizona12May 22Oct 5
California14Jun 3Sep 29
Colorado16May 3Oct 9
Connecticut14Apr 25Oct 16
Idaho31May 10Oct 2
Illinois30Apr 11Oct 23
Indiana30Apr 15Oct 25
Kansas92Apr 18Oct 22
Kentucky26Apr 18Oct 22
Maryland1Apr 29Oct 18
Massachusetts26Apr 27Oct 13
Michigan22Apr 30Oct 22
Missouri82Apr 11Oct 24
Montana1May 20Sep 20
Nevada17May 21Sep 28
New Jersey8Apr 25Oct 17
New Mexico21May 5Oct 9
New York27Apr 29Oct 21
North Carolina3May 5Oct 14
Ohio67Apr 22Oct 23
Oklahoma7Apr 20Oct 21
Oregon30Jun 2Sep 18
Pennsylvania53Apr 27Oct 21
Rhode Island4Apr 23Oct 19
Tennessee1Apr 30Oct 12
Texas2Apr 24Oct 20
Utah27May 9Oct 9
Virginia4May 2Oct 12
Washington21May 7Oct 1
West Virginia55Apr 26Oct 20

Neighboring zones

  • Zone 6a (-10 to -5°F): median last frost May 1
  • Zone 7a (0 to 5°F): median last frost Apr 18

All hardiness zones

How these numbers are made

Each ZIP code gets one zone from the USDA-ARS / PRISM 2023 ZIP tables, which use the map’s 1991–2020 average of the coldest winter night of each year. A ZIP code can span more than one zone, and USDA’s own lookup works by ZIP or address. Each NOAA station is assigned the most common zone among the closest ZIP codes listed on its station page (a tie goes to the zone of the closest of those ZIPs). Frost dates are NOAA’s 50%-probability (median) 32°F dates for each station, the same values shown on the station pages. Zone figures are the median, 10th and 90th percentile across stations; a first fall frost in January to June is counted in the following year.

Not the official USDA Plant Hardiness Zone Map. Zones shown here are the values published in the USDA-ARS / Oregon State University PRISM Group 2023 ZIP code tables, shown unaltered. For the official interactive map, visit planthardiness.ars.usda.gov.

Sources

Freeze dates are 30-year probabilities, not forecasts. Check your local forecast before planting tender plants.