{
  "address": "412842e9c5dd83e7821c5084b9c7f450",
  "category": "other",
  "question": "Is US daylight saving time in effect on 2026-07-04?",
  "answer": "yes (DST 2026: 2026-03-08 to 2026-11-01)",
  "askedBy": {
    "kind": "guest",
    "display": "method deck",
    "stamped": false,
    "id": null
  },
  "answeredBy": "method",
  "madeAt": "2026-09-30T22:39:30.722Z",
  "validUntil": null,
  "validityClass": "forever",
  "sources": [
    {
      "label": "Energy Policy Act of 2005, Section 110 (daylight saving time)",
      "url": null
    }
  ],
  "supersedes": null,
  "supersededBy": null,
  "isSeed": false,
  "seedSource": null,
  "seedAttribution": null,
  "duplicateOfQid": null,
  "publishedAt": null,
  "unpublishedAt": null,
  "voteCount": 0,
  "queuedForSubstrate": false,
  "answerMethod": "method",
  "unsourced": false,
  "source": {
    "kind": "statute",
    "value": "15 U.S.C. 260a",
    "retrieved_utc": "2026-09-30T19:41:35Z"
  },
  "qsha256": "f69a50bf999ed57b5d36eb5c7577ae05f3eeac823f71f0343eba780638b78d66",
  "runOne": null,
  "cardContractVersion": "card_contract/1",
  "deck_id": "method-deck",
  "deck_title": "Method Deck",
  "method": {
    "name": "US daylight saving time in effect?",
    "version": "1",
    "source_url_or_file": "methods/us-dst-in-effect.cjs",
    "sha256_of_method_file": "111ef2dcae1f865ce641670625bf2ca4f40971f81c1b63c91f38323f18639774"
  },
  "receipt": {
    "inSubstrate": false,
    "local": true,
    "modelCallsAtMint": 0,
    "tokensAtMint": 0
  },
  "method_deck": {
    "inputs": [
      {
        "name": "date",
        "type": "string",
        "format": "date",
        "required": true,
        "description": "ISO 8601 date to check, YYYY-MM-DD (year must be 2007 or later, when the current US rule took effect)"
      }
    ],
    "outputs": [
      {
        "name": "dst_in_effect",
        "type": "boolean",
        "description": "True if the date falls within US daylight saving time"
      },
      {
        "name": "dst_start",
        "format": "date",
        "description": "Second Sunday in March of that year, when DST begins"
      },
      {
        "name": "dst_end",
        "format": "date",
        "description": "First Sunday in November of that year, when DST ends"
      }
    ],
    "steps": [
      "Parse the date as a proleptic Gregorian civil date.",
      "Find the second Sunday of March and the first Sunday of November of the same year, using ISO weekday parity from the day-number kernel (Hinnant days_from_civil, cited above).",
      "DST is in effect for dates on or after the second Sunday of March and before the first Sunday of November.",
      "This method takes a date only (no time of day): the Act's transitions occur at 2:00 a.m. local time, so this method treats the start date itself as already in DST and the end date itself as already back to standard time."
    ],
    "constants": [
      {
        "name": "dst_start_rule",
        "value": "second Sunday in March",
        "unit": "rule",
        "source": 0
      },
      {
        "name": "dst_end_rule",
        "value": "first Sunday in November",
        "unit": "rule",
        "source": 0
      },
      {
        "name": "rule_effective_from_year",
        "value": 2007,
        "unit": "year",
        "source": 0
      }
    ],
    "examples": [
      {
        "name": "worked example",
        "inputs": {
          "date": "2026-07-04"
        },
        "expected": {
          "answer": "yes (DST 2026: 2026-03-08 to 2026-11-01)"
        },
        "check": "July 4 clearly falls between the second Sunday of March 2026 (March 8) and the first Sunday of November 2026 (Nov 1)"
      },
      {
        "name": "test vector: before DST starts",
        "inputs": {
          "date": "2026-01-15"
        },
        "expected": {
          "answer": "no (DST 2026: 2026-03-08 to 2026-11-01)"
        },
        "check": "January is always before the second Sunday of March"
      },
      {
        "name": "test vector: on the end transition date",
        "inputs": {
          "date": "2026-11-01"
        },
        "expected": {
          "answer": "no (DST 2026: 2026-03-08 to 2026-11-01)"
        },
        "check": "2026-11-01 is the first Sunday of November 2026, the documented fall-back date, so it is reported as already outside DST"
      }
    ],
    "disclaimer": null,
    "deck_category": "timezones"
  },
  "status": "minted",
  "kind": "method",
  "provenanceClass": "own_question",
  "provenance": {
    "schema": "card_provenance/2.0.0",
    "chain": [
      {
        "source": {
          "kind": "statute",
          "value": "15 U.S.C. 260a",
          "retrieved_utc": "2026-09-30T19:41:35Z"
        },
        "sha256": "c943ea62857c07091f99365be5c9d4e3c23f6b75b37753a62245169bc593d82f",
        "supersedes": null,
        "added_utc": "2026-09-30T22:39:30.722Z",
        "added_by": "method:US daylight saving time in effect?",
        "why": "the method that computed this answer",
        "check": null,
        "status_label": "pending",
        "signature": null
      }
    ]
  }
}