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Vérificateur d’heure d’été

Vérifiez si un fuseau horaire applique l’heure d’été et consultez les dates de changement.

Check a zone for a year

Next clock change in this zone

Comment ça marche

  1. The checker samples the chosen zone at every month boundary of the selected year and binary-searches between samples to find every offset change, including zones that change more than twice a year (such as Morocco’s Ramadan-related shifts).
  2. Each change is reported with the exact local date and time of the jump and both offsets (for example, clocks jump from 02:00 to 03:00, UTC−05:00 → UTC−04:00).
  3. A second panel scans forward from now for the zone’s next upcoming change, so you can see how long the current offset lasts.

Bon à savoir

  • Many zones never change: most of Asia and Africa have no DST. The tool reports what the rules actually are for the zone you pick, not an assumption.
  • Transition times come from the IANA database built into your browser. Governments can change the rules, so re-check future years when a schedule matters.
  • Year range is 1900–2200; earlier history exists but old rules were local laws rather than systematic data.
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Convertisseur de fuseaux horaires

Convertissez dates et heures entre deux fuseaux IANA du monde.

Ouvrir l’outil
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Calculateur de décalage horaire

Calculez la différence exacte en heures entre deux emplacements ou fuseaux horaires.

Ouvrir l’outil
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Horloge mondiale

Affichez simultanément l’heure locale de plusieurs métropoles internationales.

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Planificateur de réunions internationales

Trouvez le créneau horaire idéal pour vos réunions réunissant plusieurs pays.

Ouvrir l’outil

Foire aux questions

Does every country observe daylight saving time?
No. Most of Asia and Africa do not; the EU and North America, among others, do, and transition dates differ. This tool reports actual rules for the chosen zone.
What exactly does the tool show for a clock change?
The transition instant and both offsets (e.g. clocks jump from 02:00 to 03:00 local, or fall back). The exact minute and date come from your browser IANA database.
Why check a specific year?
DST rules are set by governments and do change. Checking the year you actually care about (e.g. next year’s meeting schedule) protects you from stale assumptions.