Guides

• How FrostDateCheck Calculates Your ZIP Code's Frost Dates — The exact NOAA and USDA datasets behind every ZIP page, named and sourced, and how the nearest-station join works.
• Hardiness Zone vs. Frost Date: Different Questions — USDA zones measure winter cold for perennials. Frost dates measure spring and fall freeze timing for annuals. Neither substitutes for the other.
• What the Early, Typical and Late Frost Dates Actually Mean — Why NOAA reports three dates per frost event instead of one, and how to use the spread to decide when to actually plant.
• Why Your Own Yard Might Not Match Your ZIP Code's Number — Elevation, slope, urban heat, and distance to the reporting station all shift a real frost date away from the ZIP-level normal.