Weather in Dublin in May

Shoulder season. May is shoulder season in Dublin — cheaper, quieter, and a genuine gamble. Highs sit at 13.8 °C and the day is short; this is an indoors-with-excursions month, not an outdoors-all-day one.

May ranks 5 of 12 in Dublin: past the worst of the year but short of July, which is the month to book if the dates are open.

This is persistent light rain rather than storms: 14 wet days but only 1 heavy ones. It rarely cancels anything outright, and it rarely fully clears either. A jacket beats an umbrella. Layers, and a genuinely waterproof outer — at 13.8 °C the difference between a good day and a miserable one is entirely down to what you are wearing.

What the averages hide

Averages flatten a month, and this one hides a few things: the day barely swings — 5.5 °C between the overnight low and the afternoon high. Across the twenty years measured, the hottest May day reached 21.7 °C and the coldest night fell to 3 °C, and the wettest single day dropped 27 mm — roughly 40% of the month's rain in one day.

May is statistically steady but not small: the year-to-year variation is modest in relative terms, yet the wettest May on record still delivered 128 mm against 20 mm in the driest. In a month this wet, even a tame spread is a lot of rain in absolute terms — the 67 mm average is a reasonable planning figure, not a promise.

Wind is light at 14.3 km/h, so the temperature on the page is close to the temperature on your skin, and humidity runs at 84%, which at 13.8 °C means damp rather than muggy — the kind of cold that gets into a coat and stays there.

How May sits in the year

The month is on the way up: 2.7 °C warmer than April, and June adds another 2.6 °C. Late in the month feels noticeably different from the start of it, which is worth knowing if the trip is short.

Daylight in May

15.8 hours of daylight, gaining 1.6 hours across the month. That is between Dublin's extremes of 17 and 7.6 hours, so days are long enough not to constrain the plan.

An inland climate

Despite being inland, the year stays fairly even: 13.9 °C between the year's warmest afternoons and coldest nights.

How busy it gets

Busy. Popular without being frantic; book the things you care about, improvise the rest.

Crowd levels are estimated from climate desirability and school-holiday calendars, not from visitor numbers.

May in Dublin versus nearby

If Dublin is one option among several, the nearby comparison is worth making. Galway is close enough to be a coin toss — 2 °C warmer, 3 days more rain. Cork is close enough to be a coin toss — within a degree on temperature, 3 days more rain.

So: May works, with July the better month by 9 points if the dates can move. If they cannot, nothing here should stop you booking.

Every month in Dublin

See all twelve months in Dublin, or where else to go in May.