{"abstract":"Mild-temperature heat index values are tens of degrees too high.","category":"Weather index computation","checks":8,"contract":"Input dry-bulb temperature in degF and relative humidity in percent. Compute the simple Steadman estimate 0.5*(T+61+1.2*(T-68)+0.094*RH); if the mean of that estimate and T is below 80 return it, otherwise use the Rothfusz regression with the dry adjustment (RH<13, 80<=T<=112) or the humid adjustment (RH>85, 80<=T<=87). Round to 0.1 degF.","evaluation_group":"w2-weather_index_computation-heat-index","failed_approach":"Scaling humidity by 0.94 instead of 0.094 leaves the simple branch wrong for all humid inputs.","family":"w2-weather_index_computation-heat-index-simple-estimate-base-offset","id":"FA-70861","implementations":{"attempt":{"sha256":"d985faa7b1c0cd32a5f05c60c0c73a86f6233eb7697ebf668e2c7741ad7944de","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\nimport math\nN = 1\nobservations = []\ndef solve(t_f, rh):\n    simple = 0.5 * (t_f + 61.0 + (t_f - 68.0) * 1.2 + rh * 0.94)\n    if (simple + t_f) / 2 < 80:\n        return round(simple, 1)\n    hi = (-42.379 + 2.04901523 * t_f + 10.14333127 * rh - 0.22475541 * t_f * rh\n          - 0.00683783 * t_f * t_f - 0.05481717 * rh * rh + 0.00122874 * t_f * t_f * rh\n          + 0.00085282 * t_f * rh * rh - 0.00000199 * t_f * t_f * rh * rh)\n    if rh < 13 and 80 <= t_f <= 112:\n        hi -= ((13 - rh) / 4) * math.sqrt((17 - abs(t_f - 95)) / 17)\n    elif rh > 85 and 80 <= t_f <= 87:\n        hi += ((rh - 85) / 10) * ((87 - t_f) / 5)\n    return round(hi, 1)\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\nfixtures = [[['70F at 0% RH', [70, 0], 66.7], ['70F at 5% RH', [70, 5], 66.9], ['70F at 10% RH', [70, 10], 67.2], ['70F at 12% RH', [70, 12], 67.3], ['70F at 13% RH', [70, 13], 67.3], ['70F at 40% RH', [70, 40], 68.6], ['70F at 60% RH', [70, 60], 69.5], ['70F at 85% RH', [70, 85], 70.7]], [['70F at 12% RH', [70, 12], 67.3], ['70F at 85% RH', [70, 85], 70.7], ['70F at 86% RH', [70, 86], 70.7], ['70F at 90% RH', [70, 90], 70.9], ['70F at 95% RH', [70, 95], 71.2], ['70F at 100% RH', [70, 100], 71.4], ['76F at 0% RH', [76, 0], 73.3], ['76F at 5% RH', [76, 5], 73.5]], [['70F at 60% RH', [70, 60], 69.5], ['76F at 5% RH', [76, 5], 73.5], ['76F at 10% RH', [76, 10], 73.8], ['76F at 12% RH', [76, 12], 73.9], ['76F at 13% RH', [76, 13], 73.9], ['76F at 40% RH', [76, 40], 75.2], ['76F at 60% RH', [76, 60], 76.1], ['76F at 85% RH', [76, 85], 77.3]], [['70F at 90% RH', [70, 90], 70.9], ['76F at 60% RH', [76, 60], 76.1], ['76F at 90% RH', [76, 90], 77.5], ['76F at 95% RH', [76, 95], 77.8], ['76F at 100% RH', [76, 100], 78.0], ['79F at 0% RH', [79, 0], 76.6], ['79F at 5% RH', [79, 5], 76.8], ['79F at 10% RH', [79, 10], 77.1]], [['76F at 0% RH', [76, 0], 73.3], ['76F at 100% RH', [76, 100], 78.0], ['79F at 13% RH', [79, 13], 77.2], ['79F at 40% RH', [79, 40], 78.5], ['79F at 60% RH', [79, 60], 79.4], ['79F at 85% RH', [79, 85], 80.6], ['79F at 86% RH', [79, 86], 80.6], ['79F at 90% RH', [79, 90], 80.8]]]\nfor label, args, expected in fixtures[N - 1]:\n    check(label, solve(*args), expected)\nprint(json.dumps({\"observations\": observations, \"passed\": all(x[\"passed\"] for x in observations)}, ensure_ascii=False))\nraise SystemExit(0 if all(x[\"passed\"] for x in observations) else 1)\n"},"broken":{"sha256":"b11b43c568c8d9b11cffb758f2befe1e55664b12c959715a1a763da2cd1360be","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\nimport math\nN = 1\nobservations = []\ndef solve(t_f, rh):\n    simple = 0.5 * (t_f + 61.0 + (t_f - 32.0) * 1.2 + rh * 0.094)\n    if (simple + t_f) / 2 < 80:\n        return round(simple, 1)\n    hi = (-42.379 + 2.04901523 * t_f + 10.14333127 * rh - 0.22475541 * t_f * rh\n          - 0.00683783 * t_f * t_f - 0.05481717 * rh * rh + 0.00122874 * t_f * t_f * rh\n          + 0.00085282 * t_f * rh * rh - 0.00000199 * t_f * t_f * rh * rh)\n    if rh < 13 and 80 <= t_f <= 112:\n        hi -= ((13 - rh) / 4) * math.sqrt((17 - abs(t_f - 95)) / 17)\n    elif rh > 85 and 80 <= t_f <= 87:\n        hi += ((rh - 85) / 10) * ((87 - t_f) / 5)\n    return round(hi, 1)\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\nfixtures = [[['70F at 0% RH', [70, 0], 66.7], ['70F at 5% RH', [70, 5], 66.9], ['70F at 10% RH', [70, 10], 67.2], ['70F at 12% RH', [70, 12], 67.3], ['70F at 13% RH', [70, 13], 67.3], ['70F at 40% RH', [70, 40], 68.6], ['70F at 60% RH', [70, 60], 69.5], ['70F at 85% RH', [70, 85], 70.7]], [['70F at 12% RH', [70, 12], 67.3], ['70F at 85% RH', [70, 85], 70.7], ['70F at 86% RH', [70, 86], 70.7], ['70F at 90% RH', [70, 90], 70.9], ['70F at 95% RH', [70, 95], 71.2], ['70F at 100% RH', [70, 100], 71.4], ['76F at 0% RH', [76, 0], 73.3], ['76F at 5% RH', [76, 5], 73.5]], [['70F at 60% RH', [70, 60], 69.5], ['76F at 5% RH', [76, 5], 73.5], ['76F at 10% RH', [76, 10], 73.8], ['76F at 12% RH', [76, 12], 73.9], ['76F at 13% RH', [76, 13], 73.9], ['76F at 40% RH', [76, 40], 75.2], ['76F at 60% RH', [76, 60], 76.1], ['76F at 85% RH', [76, 85], 77.3]], [['70F at 90% RH', [70, 90], 70.9], ['76F at 60% RH', [76, 60], 76.1], ['76F at 90% RH', [76, 90], 77.5], ['76F at 95% RH', [76, 95], 77.8], ['76F at 100% RH', [76, 100], 78.0], ['79F at 0% RH', [79, 0], 76.6], ['79F at 5% RH', [79, 5], 76.8], ['79F at 10% RH', [79, 10], 77.1]], [['76F at 0% RH', [76, 0], 73.3], ['76F at 100% RH', [76, 100], 78.0], ['79F at 13% RH', [79, 13], 77.2], ['79F at 40% RH', [79, 40], 78.5], ['79F at 60% RH', [79, 60], 79.4], ['79F at 85% RH', [79, 85], 80.6], ['79F at 86% RH', [79, 86], 80.6], ['79F at 90% RH', [79, 90], 80.8]]]\nfor label, args, expected in fixtures[N - 1]:\n    check(label, solve(*args), expected)\nprint(json.dumps({\"observations\": observations, \"passed\": all(x[\"passed\"] for x in observations)}, ensure_ascii=False))\nraise SystemExit(0 if all(x[\"passed\"] for x in observations) else 1)\n"},"fixed":{"sha256":"4e765227afb9adc33e3c08a2aaf671312d60947ce9d24a734b36b21b2f394aee","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\nimport math\nN = 1\nobservations = []\ndef solve(t_f, rh):\n    simple = 0.5 * (t_f + 61.0 + (t_f - 68.0) * 1.2 + rh * 0.094)\n    if (simple + t_f) / 2 < 80:\n        return round(simple, 1)\n    hi = (-42.379 + 2.04901523 * t_f + 10.14333127 * rh - 0.22475541 * t_f * rh\n          - 0.00683783 * t_f * t_f - 0.05481717 * rh * rh + 0.00122874 * t_f * t_f * rh\n          + 0.00085282 * t_f * rh * rh - 0.00000199 * t_f * t_f * rh * rh)\n    if rh < 13 and 80 <= t_f <= 112:\n        hi -= ((13 - rh) / 4) * math.sqrt((17 - abs(t_f - 95)) / 17)\n    elif rh > 85 and 80 <= t_f <= 87:\n        hi += ((rh - 85) / 10) * ((87 - t_f) / 5)\n    return round(hi, 1)\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\nfixtures = [[['70F at 0% RH', [70, 0], 66.7], ['70F at 5% RH', [70, 5], 66.9], ['70F at 10% RH', [70, 10], 67.2], ['70F at 12% RH', [70, 12], 67.3], ['70F at 13% RH', [70, 13], 67.3], ['70F at 40% RH', [70, 40], 68.6], ['70F at 60% RH', [70, 60], 69.5], ['70F at 85% RH', [70, 85], 70.7]], [['70F at 12% RH', [70, 12], 67.3], ['70F at 85% RH', [70, 85], 70.7], ['70F at 86% RH', [70, 86], 70.7], ['70F at 90% RH', [70, 90], 70.9], ['70F at 95% RH', [70, 95], 71.2], ['70F at 100% RH', [70, 100], 71.4], ['76F at 0% RH', [76, 0], 73.3], ['76F at 5% RH', [76, 5], 73.5]], [['70F at 60% RH', [70, 60], 69.5], ['76F at 5% RH', [76, 5], 73.5], ['76F at 10% RH', [76, 10], 73.8], ['76F at 12% RH', [76, 12], 73.9], ['76F at 13% RH', [76, 13], 73.9], ['76F at 40% RH', [76, 40], 75.2], ['76F at 60% RH', [76, 60], 76.1], ['76F at 85% RH', [76, 85], 77.3]], [['70F at 90% RH', [70, 90], 70.9], ['76F at 60% RH', [76, 60], 76.1], ['76F at 90% RH', [76, 90], 77.5], ['76F at 95% RH', [76, 95], 77.8], ['76F at 100% RH', [76, 100], 78.0], ['79F at 0% RH', [79, 0], 76.6], ['79F at 5% RH', [79, 5], 76.8], ['79F at 10% RH', [79, 10], 77.1]], [['76F at 0% RH', [76, 0], 73.3], ['76F at 100% RH', [76, 100], 78.0], ['79F at 13% RH', [79, 13], 77.2], ['79F at 40% RH', [79, 40], 78.5], ['79F at 60% RH', [79, 60], 79.4], ['79F at 85% RH', [79, 85], 80.6], ['79F at 86% RH', [79, 86], 80.6], ['79F at 90% RH', [79, 90], 80.8]]]\nfor label, args, expected in fixtures[N - 1]:\n    check(label, solve(*args), expected)\nprint(json.dumps({\"observations\": observations, \"passed\": all(x[\"passed\"] for x in observations)}, ensure_ascii=False))\nraise SystemExit(0 if all(x[\"passed\"] for x in observations) else 1)\n"}},"limitations":"Stipulated deterministic teaching model of an operational weather index; coefficients and thresholds are fixed by the contract and no claim of standards conformance is made. This reproducer isolates one failure mechanism. Results cover the supplied fixtures. Variants within a family share a test contract and should remain grouped when constructing evaluation splits. Related mechanisms with a shared evaluation_group must also remain together; these controlled models are not independent production incidents.","method":"Deterministic executable model with adversarial boundary fixtures.","provenance":{"created_by":"Failure Map","dependencies":"Python standard library","family":"w2-weather_index_computation-heat-index-simple-estimate-base-offset","generated_at":"2026-09-29T14:48:24.559816+00:00","license":"CC0-1.0","python":"3.12.14","seed":1,"split":"open-access"},"relevance":"Heat advisories are issued from this value; a wrong branch changes public warnings.","repair":"Use 1.2*(T - 68) in the simple estimate.","root_cause":"The simple Steadman estimate offsets temperature from the freezing point (32) instead of 68 degF.","sha256":"d325545fea2562faa02a350dd261b05ee58a6d79fd62d94a9158ff0efc36034f","title":"Heat index regression: simple estimate base offset · case 01","variant":1,"variant_policy":"Five numbered records share a model and may reuse boundary fixtures.","verification":{"attempt":{"elapsed_ms":37.755,"exit_code":1,"observations":[{"actual":66.7,"check":"70F at 0% RH","expected":66.7,"passed":true},{"actual":69.0,"check":"70F at 5% RH","expected":66.9,"passed":false},{"actual":71.4,"check":"70F at 10% RH","expected":67.2,"passed":false},{"actual":72.3,"check":"70F at 12% RH","expected":67.3,"passed":false},{"actual":72.8,"check":"70F at 13% RH","expected":67.3,"passed":false},{"actual":85.5,"check":"70F at 40% RH","expected":68.6,"passed":false},{"actual":75.9,"check":"70F at 60% RH","expected":69.5,"passed":false},{"actual":69.0,"check":"70F at 85% RH","expected":70.7,"passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"70F at 0% RH\", \"actual\": 66.7, \"expected\": 66.7, \"passed\": true}, {\"check\": \"70F at 5% RH\", \"actual\": 69.0, \"expected\": 66.9, \"passed\": false}, {\"check\": \"70F at 10% RH\", \"actual\": 71.4, \"expected\": 67.2, \"passed\": false}, {\"check\": \"70F at 12% RH\", \"actual\": 72.3, \"expected\": 67.3, \"passed\": false}, {\"check\": \"70F at 13% RH\", \"actual\": 72.8, \"expected\": 67.3, \"passed\": false}, {\"check\": \"70F at 40% RH\", \"actual\": 85.5, \"expected\": 68.6, \"passed\": false}, {\"check\": \"70F at 60% RH\", \"actual\": 75.9, \"expected\": 69.5, \"passed\": false}, {\"check\": \"70F at 85% RH\", \"actual\": 69.0, \"expected\": 70.7, \"passed\": false}], \"passed\": false}\n"},"broken":{"elapsed_ms":38.776,"exit_code":1,"observations":[{"actual":88.3,"check":"70F at 0% RH","expected":66.7,"passed":false},{"actual":88.5,"check":"70F at 5% RH","expected":66.9,"passed":false},{"actual":88.8,"check":"70F at 10% RH","expected":67.2,"passed":false},{"actual":88.9,"check":"70F at 12% RH","expected":67.3,"passed":false},{"actual":88.9,"check":"70F at 13% RH","expected":67.3,"passed":false},{"actual":77.0,"check":"70F at 40% RH","expected":68.6,"passed":false},{"actual":75.9,"check":"70F at 60% RH","expected":69.5,"passed":false},{"actual":69.0,"check":"70F at 85% RH","expected":70.7,"passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"70F at 0% RH\", \"actual\": 88.3, \"expected\": 66.7, \"passed\": false}, {\"check\": \"70F at 5% RH\", \"actual\": 88.5, \"expected\": 66.9, \"passed\": false}, {\"check\": \"70F at 10% RH\", \"actual\": 88.8, \"expected\": 67.2, \"passed\": false}, {\"check\": \"70F at 12% RH\", \"actual\": 88.9, \"expected\": 67.3, \"passed\": false}, {\"check\": \"70F at 13% RH\", \"actual\": 88.9, \"expected\": 67.3, \"passed\": false}, {\"check\": \"70F at 40% RH\", \"actual\": 77.0, \"expected\": 68.6, \"passed\": false}, {\"check\": \"70F at 60% RH\", \"actual\": 75.9, \"expected\": 69.5, \"passed\": false}, {\"check\": \"70F at 85% RH\", \"actual\": 69.0, \"expected\": 70.7, \"passed\": false}], \"passed\": false}\n"},"fixed":{"elapsed_ms":37.109,"exit_code":0,"observations":[{"actual":66.7,"check":"70F at 0% RH","expected":66.7,"passed":true},{"actual":66.9,"check":"70F at 5% RH","expected":66.9,"passed":true},{"actual":67.2,"check":"70F at 10% RH","expected":67.2,"passed":true},{"actual":67.3,"check":"70F at 12% RH","expected":67.3,"passed":true},{"actual":67.3,"check":"70F at 13% RH","expected":67.3,"passed":true},{"actual":68.6,"check":"70F at 40% RH","expected":68.6,"passed":true},{"actual":69.5,"check":"70F at 60% RH","expected":69.5,"passed":true},{"actual":70.7,"check":"70F at 85% RH","expected":70.7,"passed":true}],"passed":true,"stderr":"","stdout":"{\"observations\": [{\"check\": \"70F at 0% RH\", \"actual\": 66.7, \"expected\": 66.7, \"passed\": true}, {\"check\": \"70F at 5% RH\", \"actual\": 66.9, \"expected\": 66.9, \"passed\": true}, {\"check\": \"70F at 10% RH\", \"actual\": 67.2, \"expected\": 67.2, \"passed\": true}, {\"check\": \"70F at 12% RH\", \"actual\": 67.3, \"expected\": 67.3, \"passed\": true}, {\"check\": \"70F at 13% RH\", \"actual\": 67.3, \"expected\": 67.3, \"passed\": true}, {\"check\": \"70F at 40% RH\", \"actual\": 68.6, \"expected\": 68.6, \"passed\": true}, {\"check\": \"70F at 60% RH\", \"actual\": 69.5, \"expected\": 69.5, \"passed\": true}, {\"check\": \"70F at 85% RH\", \"actual\": 70.7, \"expected\": 70.7, \"passed\": true}], \"passed\": true}\n"}},"verified":true,"visibility":"public"}