Weather in Greymouth in December

Shoulder season. December is shoulder season in Greymouth — cheaper, quieter, and a genuine gamble. You should expect rain on 18 days of the month, which is more days wet than dry.

December ranks 4 of 12 in Greymouth: past the worst of the year but short of February, which is the month to book if the dates are open.

This is wet-season rain: 18 wet days and 7 genuinely heavy ones, which in this climate means concentrated downpours rather than all-day grey. The pattern is usually a clear morning and a loud afternoon, so front-load the day and stop fighting the 3pm hour. Nothing specialised needed — this is the month you pack for the trip rather than for the weather.

What the averages hide

Averages flatten a month, and this one hides a few things: it never really gets hot: not one day in an average December reaches 30 °C; the day barely swings — 5.6 °C between the overnight low and the afternoon high. Across the twenty years measured, the hottest December day reached 23.7 °C and the coldest night fell to 6.7 °C, and the wettest single day dropped 66 mm — roughly 35% of the month's rain in one day.

December is statistically steady but not small: the year-to-year variation is modest in relative terms, yet the wettest December on record still delivered 268 mm against 87 mm in the driest. In a month this wet, even a tame spread is a lot of rain in absolute terms — the 190 mm average is a reasonable planning figure, not a promise.

Wind is light at 4.3 km/h, so the temperature on the page is close to the temperature on your skin, and humidity runs at 84%, high enough to notice on the warm days without dominating them.

How December sits in the year

Temperatures hold steady either side: 16 °C in November, 18 here, 19.2 in January. Nothing about the timing within the month matters much.

Daylight in December

December is at or near the longest days of Greymouth's year: 15.3 hours of daylight, holding steady all month. Evenings are the real gain — dinner outdoors still happens in full light.

Sea temperature

The sea sits at about 16.4 °C in December — cold — a quick dip rather than a swim, and a wetsuit if you are in for longer. The sea peaks at 18.5 °C in February and bottoms out at 13.3 °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

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.

December in Greymouth versus nearby

If Greymouth is one option among several, the nearby comparison is worth making. Waikowhai is close enough to be a coin toss — within a degree on temperature, 1 day less rain. Christchurch is a better bet in December — 4.1 °C warmer, 4 days less rain.

So: December works, with February the better month by 13 points if the dates can move. If they cannot, nothing here should stop you booking.

Every month in Greymouth

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