{
  "updated": "2026-11-08",
  "source": "backtest",
  "source_label": "Testing on five past winters (2021/22 to 2025/26). Live results replace these as this winter's forecasts are verified.",
  "resorts_forecast": 1032,
  "resorts_verified": 784,
  "baselines": {
    "bluebird_right": 30,
    "powder10_right": 5,
    "powder20_right": 1.5,
    "bluebird_exact": 29.8,
    "powder10_exact": 5.2
  },
  "leads": [
    {
      "day": 0,
      "label": "Same day",
      "bluebird_right": 79,
      "bluebird_caught": 86,
      "powder10_right": 56,
      "powder10_caught": 65,
      "powder20_right": 49,
      "powder20_caught": 44,
      "basis": "281,202 resort-days (bluebird), 610,119 (powder)"
    },
    {
      "day": 1,
      "label": "Day 1",
      "bluebird_right": 76,
      "bluebird_caught": 83,
      "powder10_right": 51,
      "powder10_caught": 63,
      "powder20_right": 39,
      "powder20_caught": 47,
      "basis": "278,240 resort-days (bluebird), 694,412 (powder)"
    },
    {
      "day": 2,
      "label": "Day 2",
      "bluebird_right": 74,
      "bluebird_caught": 82,
      "powder10_right": 51,
      "powder10_caught": 63,
      "powder20_right": 38,
      "powder20_caught": 46,
      "basis": "276,691 resort-days (bluebird), 690,652 (powder)"
    },
    {
      "day": 3,
      "label": "Day 3",
      "bluebird_right": 71,
      "bluebird_caught": 81,
      "powder10_right": 50,
      "powder10_caught": 58,
      "powder20_right": 37,
      "powder20_caught": 44,
      "basis": "275,142 resort-days (bluebird), 686,888 (powder)"
    },
    {
      "day": 4,
      "label": "Day 4",
      "bluebird_right": 67,
      "bluebird_caught": 78,
      "powder10_right": 45,
      "powder10_caught": 57,
      "powder20_right": 35,
      "powder20_caught": 39,
      "basis": "273,593 resort-days (bluebird), 683,132 (powder)"
    },
    {
      "day": 5,
      "label": "Day 5",
      "bluebird_right": 63,
      "bluebird_caught": 75,
      "powder10_right": 40,
      "powder10_caught": 50,
      "powder20_right": 28,
      "powder20_caught": 35,
      "basis": "272,044 resort-days (bluebird), 679,366 (powder)"
    }
  ],
  "known_gaps": [
    "Days 1 to 5 are scored for the evening forecast (issued around 18:00 UTC, the one behind the evening alert). The morning update, issued around 07:00 UTC, scores up to 3 points lower at each range. Same-day figures come from the morning forecast.",
    "Bluebird is checked against weather stations at 321 resorts. Satellite sunshine checks all 1,032 resorts, but so far only for same-day forecasts.",
    "In France, powder is checked against Météo-France snow simulations for each mountain range at mid-mountain height. These are a model, not measurements.",
    "Stations and satellite pixels measure one spot. Sun at the base can differ from sun at the top.",
    "Big powder days (20 cm+) are rare, about 1.5% of days, so those figures are less certain.",
    "Forecasts more than 5 days ahead are not scored, and we don't make them."
  ],
  "countries": [
    {
      "code": "AT",
      "name": "Austria",
      "bluebird_right": 80,
      "bluebird_caught": 86,
      "powder10_right": 56,
      "powder10_caught": 62,
      "powder10_base": 4.2,
      "bluebird_base": 30.0
    },
    {
      "code": "CH",
      "name": "Switzerland",
      "bluebird_right": 80,
      "bluebird_caught": 87,
      "powder10_right": 57,
      "powder10_caught": 68,
      "powder10_base": 7.3,
      "bluebird_base": 34.1
    },
    {
      "code": "DE",
      "name": "Germany",
      "bluebird_right": 79,
      "bluebird_caught": 84,
      "powder10_right": 53,
      "powder10_caught": 46,
      "powder10_base": 2.1,
      "bluebird_base": 21.4
    },
    {
      "code": "FR",
      "name": "France",
      "bluebird_right": 77,
      "bluebird_caught": 85,
      "powder10_right": 54,
      "powder10_caught": 66,
      "powder10_base": 3.5,
      "bluebird_base": 30.8
    },
    {
      "code": "IT",
      "name": "Italy",
      "bluebird_right": 74,
      "bluebird_caught": 83,
      "powder10_right": 51,
      "powder10_caught": 61,
      "powder10_base": 6.0,
      "bluebird_base": 29.0
    }
  ],
  "countries_note": "Same-day forecasts by country. Bluebird is checked against weather stations, powder against high-altitude snow stations and Météo-France snow simulations. Each country is compared with how often it happens there.",
  "comparison": {
    "what": "Same-day bluebird forecasts: Bluepow blend vs ECMWF alone, calibrated to each resort the same way",
    "basis": "281,202 resort-days, same days for both",
    "bluepow": {
      "right": 79,
      "caught": 86
    },
    "ecmwf_alone": {
      "right": 70,
      "caught": 77
    }
  },
  "resorts_bluebird_stations": 321,
  "resorts_satellite": 1032,
  "truth": {
    "bluebird": "weather-station sunshine at 321 resorts",
    "bluebird_satellite": "satellite sunshine (EUMETSAT CM SAF SARAH-3) at all 1,032 resorts",
    "powder": "high-altitude snow stations and Météo-France snow simulations, at 784 resorts"
  },
  "satellite": {
    "what": "Same-day bluebird forecasts checked against satellite sunshine at every resort",
    "basis": "940,152 resort-days at 1,032 resorts",
    "right": 76,
    "caught": 76,
    "base": 32,
    "countries": [
      {
        "code": "AT",
        "name": "Austria",
        "right": 78,
        "caught": 77,
        "base": 29.8
      },
      {
        "code": "CH",
        "name": "Switzerland",
        "right": 73,
        "caught": 73,
        "base": 29.2
      },
      {
        "code": "DE",
        "name": "Germany",
        "right": 81,
        "caught": 79,
        "base": 25.7
      },
      {
        "code": "FR",
        "name": "France",
        "right": 75,
        "caught": 74,
        "base": 32.7
      },
      {
        "code": "IT",
        "name": "Italy",
        "right": 77,
        "caught": 76,
        "base": 39.3
      }
    ]
  }
}