Weather in Cork in December

The month to avoid. December is the month most people should skip in Cork. You should expect rain on 20 days of the month, which is more days wet than dry.

December ranks 11 of 12 — near the bottom of Cork's year. July is the month that works, and the swing between the two is 36 points, which is a different holiday rather than a slightly better one.

Rain on 20 of the month's 31 days, 4 of them heavy. At that frequency a wet-weather backup is not a contingency, it is the itinerary — book the indoor things first and treat the clear days as the bonus. Layers, and a genuinely waterproof outer — at 9.1 °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 — 4.2 °C between the overnight low and the afternoon high. Across the twenty years measured, the hottest December day reached 14.2 °C and the coldest night fell to -4.8 °C, and the wettest single day dropped 31 mm — roughly 25% of the month's rain in one day.

December is moderately variable: 51 mm in the driest year against 345 mm in the wettest, around an average of 124 mm. Roughly two Decembers in three land near that average, and the third does something else entirely.

Wind is light at 15.5 km/h, so the temperature on the page is close to the temperature on your skin, and humidity runs at 94%, which at 9.1 °C means damp rather than muggy — the kind of cold that gets into a coat and stays there.

How December sits in the year

Temperatures hold steady either side: 10.8 °C in November, 9.1 here, 8.7 in January. Nothing about the timing within the month matters much.

Daylight in December

December sits at the dark end of Cork's year — 7.8 hours of daylight against 16.7 at midsummer, losing 0.4 hours across the month. Sightseeing days are genuinely shorter, and an itinerary built for summer will not fit.

Sea temperature

The sea sits at about 10.9 °C in December — too cold to swim without a wetsuit. The sea peaks at 16.6 °C in August and bottoms out at 9 °C — water lags the air by a month or two, which is why the best swimming often comes after the best weather.

How busy it gets

Off season. The genuine off season: cheapest by a distance, with the caveat that some tours and restaurants close entirely.

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

December in Cork versus nearby

If Cork is one option among several, the nearby comparison is worth making. Galway is close enough to be a coin toss — within a degree on temperature, 1 day less rain. Dublin is close enough to be a coin toss — within a degree on temperature, 2 days less rain.

So: December is a compromise. July is 35 points better and is what Cork is actually like at its best — worth moving the trip for if that is possible, and worth adjusting expectations for if it is not.

Every month in Cork

See all twelve months in Cork, or where else to go in December.