"Under the current directive, all [EU] member states switch to summer time on the last Sunday in March and back to their standard time ('winter time') on the last Sunday in October." A distinction without a difference, but Ireland is a MS with standard time in summer, IST=Irish Standard Time. Quirk of history, where you change the law because your neighbour did and you don't feel like undoing all that when neighbour changed their mind. https://www.rte.ie/lifestyle/living/2026/1019/1564728-everything-you-need-to-know-about-the-clocks-changing-in-2026/ #standardtime #ireland #eu #rte