Joel's APIs

A collection of useful APIs for developers and data enthusiasts.

Frost Date API

Get frost date predictions for any US location based on NOAA Climate Normals data. Returns first and last frost dates with probability percentages to help with garden planning and agricultural decisions.

Endpoint

GET apis.joelgrant.dev/api/v1/frost/{zip_code}

Example Request

curl --location 'apis.joelgrant.dev/api/v1/frost/68923'

Response Format

{
  "zip_code": "68923",
  "data": {
    "zip_code": "68923",
    "location": {
      "city": "Atlanta",
      "state": "NE",
      "latitude": 40.35909,
      "longitude": -99.46833
    },
    "weather_station": {
      "station_id": "USC00253910",
      "name": "HOLDREGE, NE US",
      "latitude": 40.4517,
      "longitude": -99.3803,
      "distance_km": 12.71
    },
    "frost_dates": {
      "first_frost_32f": {
        "10%": "09/28",
        "20%": "10/01",
        "30%": "10/05",
        "40%": "10/08",
        "50%": "10/11",
        "60%": "10/13",
        "70%": "10/16",
        "80%": "10/19",
        "90%": "10/22"
      },
      "last_frost_32f": {
        "10%": "05/15",
        "20%": "05/10",
        "30%": "05/07",
        "40%": "05/04",
        "50%": "05/02",
        "60%": "04/30",
        "70%": "04/27",
        "80%": "04/23",
        "90%": "04/17"
      }
    }
  },
  "meta": {
    "api_version": "v1",
    "timestamp": "2025-08-22T22:53:14Z",
    "data_source": "NOAA Climate Normals 1991-2020"
  }
}

How It Works

  • Location Lookup: Uses zip code to find the exact coordinates and nearest weather station
  • Climate Data: Pulls from NOAA Climate Normals 1991-2020 dataset for historical accuracy
  • Probability Calculations: Returns frost dates at different probability levels (10% = earliest likely, 90% = latest likely)
  • First Frost: Probability of first 32°F temperature in fall/winter
  • Last Frost: Probability of last 32°F temperature in spring

Data Attribution

Frost date predictions are based on historical climate data from the National Oceanic and Atmospheric Administration (NOAA).

Data Source: NOAA Climate Normals 1991-2020
U.S. Climate Normals provide a 30-year average of temperature, precipitation, and other climate variables for weather stations across the United States.