When countries changed their daylight saving rules

    Almost nobody writes this down, and it matters more often than it should. A scheduling assumption that was right two years ago can be quietly wrong now — and the change usually left no announcement.

    44

    recorded rule changes

    28

    rule sets that have changed

    38

    countries affected

    Where this comes from

    Every row below is a change recorded in the IANA Time Zone Database, the same data that keeps clocks correct on Linux, macOS, Android and most servers. IANA maintainers track the official announcements, so these dates are the dates the rules actually moved — not summaries of them.

    Rules are grouped the way the database groups them. One rule set governs many countries: the EU rule covers most of Europe, and the US rule covers every American zone. A change to a shared rule changes many countries on the same day, which is why it is easy to miss.

    All recorded changes, most recent first

    Every rule set with at least one recorded change. If a scheduling rule you rely on was written before the year at the top of a card, it is worth rechecking.

    Chile

    Now starts on the first Sunday in September

    1. 2019second Sunday in August first Sunday in September
    2. 2016first Sunday in September second Sunday in August
    3. 2012second Sunday in October first Sunday in September
    4. 19701st in September second Sunday in October
    Covers: Chile (Santiago, Puente Alto, Antofagasta, Viña del Mar)

    Palestine

    Now starts on the 25th in May

    1. 2016last Thursday in March last Saturday in March
    2. 2012third Friday in April last Thursday in March

    Fiji

    Now starts on the 20th in December

    1. 2014third Sunday in October first Sunday in November
    Covers: Fiji (Suva, Nasinu, Lautoka)

    Zion

    Now starts on the fourth Friday in March

    1. 2013last Friday in April fourth Friday in March
    Covers: Israel (Jerusalem, Tel Aviv, Haifa, Rishon LeZion)

    Cuba

    Now starts on the second Sunday in March

    1. 2013first Sunday in April second Sunday in March
    2. 1990second Sunday in March first Sunday in April
    3. 1986first Sunday in May second Sunday in March
    4. 1981last Sunday in April first Sunday in May
    Covers: Cuba (Havana, Santiago de Cuba, Camagüey)

    Haiti

    Now starts on the second Sunday in March

    1. 2012first Sunday in April second Sunday in March
    2. 1988last Sunday in April first Sunday in April
    Covers: Haiti (Port-au-Prince, Carrefour, Delmas)

    AN

    Now starts on the first Sunday in October

    1. 2008last Sunday in October first Sunday in October
    Covers: Australia (Sydney, Canberra, Newcastle, Wollongong)

    AS

    Now starts on the first Sunday in October

    1. 2008last Sunday in October first Sunday in October
    Covers: Australia (Adelaide, Broken Hill, Mount Gambier)

    Brazil

    Now starts on the first Sunday in November

    1. 2008second Sunday in October third Sunday in October
    2. 19931st in December second Sunday in October
    Covers: Brazil (São Paulo, Rio de Janeiro, Brasília, Belo Horizonte)

    AV

    Now starts on the first Sunday in October

    1. 2008last Sunday in October first Sunday in October
    Covers: Australia (Melbourne, Geelong, Ballarat, Bendigo)

    LH

    Now starts on the first Sunday in October

    1. 2008last Sunday in October first Sunday in October
    2. 1987last Sunday in October last Sunday in October (clocks forward by 1h → 0.5h)

    US

    Now starts on the second Sunday in March

    1. 2007first Sunday in April second Sunday in March
    2. 1987last Sunday in April first Sunday in April
    Covers: Mexico (Tijuana, Juárez, Mexicali) · United States (New York, Los Angeles, Chicago, Houston)

    Canada

    Now starts on the second Sunday in March

    1. 2007first Sunday in April second Sunday in March
    2. 1987last Sunday in April first Sunday in April
    Covers: Bahamas (Nassau) · Canada (Toronto, Montreal, Ottawa, Quebec City)

    NZ

    Now starts on the last Sunday in September

    1. 2007first Sunday in October last Sunday in September
    2. 1990last Sunday in October first Sunday in October
    3. 1975last Sunday in September last Sunday in October (clocks forward by 0.5h → 1h)
    Covers: New Zealand (Auckland, Wellington, Christchurch, Hamilton)

    USback

    Now starts on the second Sunday in March

    1. 2007first Sunday in April second Sunday in March
    2. 1987last Sunday in April first Sunday in April

    Chatham

    Now starts on the last Sunday in September

    1. 2007first Sunday in October last Sunday in September
    2. 1990last Sunday in October first Sunday in October

    Thule

    Now starts on the second Sunday in March

    1. 2007first Sunday in April second Sunday in March

    Uruguay

    Now starts on the first Sunday in October

    1. 2006last Sunday in October first Sunday in October (clocks forward by 0.5h → 1h)
    Covers: Uruguay (Montevideo, Salto, Ciudad de la Costa, Paysandú)

    Mongol

    Now starts on the last Saturday in March

    1. 2002last Sunday in March last Saturday in March
    Covers: Mongolia (Ulaanbaatar, Erdenet, Darkhan)

    Egypt

    Now starts on the last Friday in April

    1. 19951st in May last Friday in April
    Covers: Egypt (Cairo, Alexandria, Giza, Shubra El Kheima)

    Lebanon

    Now starts on the last Sunday in March

    1. 19931st in May last Sunday in March
    Covers: Lebanon (Beirut, Tripoli, Sidon)

    AT

    Now starts on the first Sunday in October

    1. 1991last Sunday in October first Sunday in October
    Covers: Australia (Hobart, Launceston, Devonport)

    Iraq

    Now starts on the 1st in April

    1. 1991last Sunday in March 1st in April
    Covers: Iraq (Baghdad, Basra, Mosul, Erbil)

    Arg

    Now starts on the third Sunday in October

    1. 198915th in October third Sunday in October
    Covers: Argentina (Buenos Aires, Córdoba, Rosario, Tucumán)

    EU

    Now starts on the last Sunday in March

    1. 1981first Sunday in April last Sunday in March
    Covers: Austria (Vienna, Graz, Linz, Salzburg) · Belgium (Brussels, Antwerp, Ghent, Charleroi) · Bulgaria (Sofia, Plovdiv, Varna, Burgas) · Denmark (Copenhagen, Aarhus, Odense, Aalborg) · Finland (Helsinki, Espoo, Tampere, Vantaa) · Germany (Berlin, Hamburg, Munich, Cologne) · Greece (Athens, Thessaloniki, Patras) · Italy (Rome, Milan, Naples, Turin) · Netherlands (Amsterdam, Rotterdam, The Hague, Utrecht) · Norway (Oslo, Bergen, Trondheim, Stavanger) · Poland (Warsaw, Krakow, Łódź, Wrocław) · Portugal (Lisbon, Porto, Vila Nova de Gaia, Amadora) · Romania (Bucharest, Cluj-Napoca, Timișoara, Iași) · Spain (Madrid, Barcelona, Valencia, Seville) · Sweden (Stockholm, Gothenburg, Malmö, Uppsala) · Switzerland (Zurich, Geneva, Basel, Bern) · Ukraine (Kiev, Kharkiv, Odessa, Dnipro) · United Kingdom (London, Birmingham, Manchester, Glasgow)

    GB-Eire

    Now starts on the last Sunday in March

    1. 1981third Sunday in March last Sunday in March
    Covers: Ireland (Dublin, Cork, Limerick, Galway)

    E-Eur

    Now starts on the last Sunday in March

    1. 1981first Sunday in April last Sunday in March

    C-Eur

    Now starts on the last Sunday in March

    1. 1981first Sunday in April last Sunday in March
    Covers: Hungary (Budapest, Debrecen, Szeged, Miskolc)

    Reading this page

    The rule names come from the database and are not always meaningful: AN and AS are the Australian northern and southern rule sets, and Zion is Israel's. The countries each rule covers are listed underneath for that reason.

    Single-year exceptions are left out. Several rule sets have one-off lines for individual years — the United States did in 1974 and 1975 — which make a stable rule look like it was churning. Only rules that lasted three years or more are reported here as changes.

    Each city page shows the same figures for its own zone, alongside when its standard offset last moved. That is a different question, and one people confuse constantly: a country can change when its clocks go forward without changing what time it is.

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