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Temperatures in June can range from 5°C to 20°C (40F-70F), but general stay between 13°C and 16°C (55F-60F). Dublin can be fairly windy, which will make it seem a little colder, but a jumper (sweater) or light jacket should usually be sufficient to keep you warm.
A general rule for Irish weather is that if you don't like the current iteration, wait five minutes and you'll have a new one.
It's one of the few counteries countries where it's not uncommon to carry an umberella and sunglasses with you at the same time
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