Reviewed calculator profile · zip

Frost Date Calculator
ZIP 48201.

ZIP 48201 is matched locally to the bundled Census/NOAA station dataset. The rendered matrix result includes the selected station, distance, 32°F probability dates and USDA zone instead of waiting for a browser submit.

Evidence modereference dataZIP 48201 is applied to the real calculator input; unconfirmed high-risk values remain unconfirmed.
Value-level evidence

ZIP 48201 profile

Reviewed 2026-08-28

ZIP 48201 is matched locally to the bundled Census/NOAA station dataset. The rendered matrix result includes the selected station, distance, 32°F probability dates and USDA zone instead of waiting for a browser submit.

  • The ZIP is a local lookup key, not a weather station; the nearest representative station can be overridden.
  • NOAA 1991–2020 normals are probability references, while USDA hardiness zone is displayed separately and never converted into a frost date.
Applied inputzip: 48201
Evidence modereference data
Next review2027-02-28
Preselected reference valueZIP 48201This value is applied to the real calculator input. Adjust the remaining assumptions and verify the visible source before relying on the result.
Reference calculation

Enter your details.

ZIP matching uses the bundled Census/NOAA file in this browser; the ZIP is not uploaded. Optional site analytics loads only after consent and measures broad use, not calculator inputs or result text.

Matched locally to a nearby NOAA climate-normal station; the ZIP is not uploaded.
NOAA normals supply month/day probabilities; this year places them on your calendar.
Probability that the last spring freeze occurs later, or the first fall freeze occurs earlier, than the shown date.
Leave blank for the locally matched station, or paste an annual/seasonal normals station ID.

Your result
May 6, 2026 – Oct 17, 2026

The selected NOAA 32°F probability dates are placed in 2026. There is a 10% chance the last spring freeze occurs later, and a 10% chance the first fall freeze occurs earlier, than the dates shown.

ZIP Code48201
Planning year2026
Probability threshold10%Chance the last spring freeze is later / first fall freeze is earlier than the shown date
NOAA station overrideAutomatic nearby-station match
USDA 2023 hardiness zone6bCold-tolerance reference only; not used in the freeze-date calculation
NOAA climate-normal stationDETROIT CITY AP, MI USUSW00014822 · 8 km from ZIP center · 191 m elevation
Normal qualityStandard (24+ years expected)29 years used in the weakest selected normal
Last spring 32°F probability dateMay 6, 202610% chance of a later freeze
First fall 32°F probability dateOct 17, 202610% chance of an earlier freeze
Date-to-date span164 daysCalculated between the two selected probability dates
NOAA freeze-free normal208 daysNOAA models the period distribution directly, so it can differ from simple date subtraction
Nearby station candidatesDETROIT CITY AP, MI US (USW00014822, 8 km); DEARBORN, MI US (USC00202015, 15 km); DETROIT METRO AP, MI US (USW00094847, 26 km)Override the station when terrain, elevation or coast exposure makes another station more representative
May 6, 2026Last-spring 32°F probability date
Oct 17, 2026First-fall 32°F probability date
Calendar options

Add to calendar

Choose a calendar service, then confirm the event. Downloading an .ics file does not add it until you open or import it.

Read before relying

Context matters.

  • Climate normals describe 1991–2020 probability distributions, not this year's weather. Check the current forecast before planting, transplanting or protecting crops.
  • Air temperature at a station is not leaf-surface frost. Elevation, slope, urban heat, cold-air drainage and local exposure can move garden conditions materially.
  • USDA hardiness zone is shown only as a separate perennial cold-tolerance reference.
Rule set 2.0.0

Sources & scope

Source & calculation QA reviewed

The calculation guide and this source trail show what the result means, where the rule came from and when it was last reviewed. This is source-and-calculation QA, not a claim of medical, legal, tax or other professional review; time-sensitive decisions still belong with the linked authority.

JurisdictionUnited States — NOAA 1991–2020 station normals, Census ZCTA matching and USDA 2023 hardiness-zone reference
Last reviewed2026-08-28
Next review due2027-02-28
Review scopeCalcSpan source & calculation QA
PrivacyInputs stay local · coarse usage analytics only after consent