Weather in Invercargill in December

Shoulder season. December sits in between. You will get good days and you will lose some. You should expect rain on 17 days of the month, which is more days wet than dry.

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

Rain on 17 days, 3 of them heavy. Enough to need a plan B, not enough to need a plan around it. Pack for 16.1 °C days and 10.6 °C nights; the spread matters more here than any single number.

What the averages hide

Averages flatten a month, and this one hides a few things: 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 24.1 °C and the coldest night fell to 6.1 °C, and the wettest single day dropped 40 mm — roughly 38% 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 207 mm against 38 mm in the driest. In a month this wet, even a tame spread is a lot of rain in absolute terms — the 105 mm average is a reasonable planning figure, not a promise.

Wind is light at 14.8 km/h, so the temperature on the page is close to the temperature on your skin, and humidity runs at 78%, high enough to notice on the warm days without dominating them.

How December sits in the year

Temperatures hold steady either side: 14.1 °C in November, 16.1 here, 17 in January. Nothing about the timing within the month matters much.

Daylight in December

December is at or near the longest days of Invercargill's year: 15.8 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 11.7 °C in December — too cold to swim without a wetsuit. The sea peaks at 12.7 °C in February and bottoms out at 9.9 °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

Peak season. Expect the highest prices of the year and to be booking well ahead. If the dates are flexible, April is the trade worth considering — 13 points weaker on weather, and materially quieter.

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

December in Invercargill versus nearby

If Invercargill is one option among several, the nearby comparison is worth making. Papatowai is a better bet in December — within a degree on temperature, 2 days less rain. Te Anau is close enough to be a coin toss — within a degree on temperature, 4 days more rain.

So: December works, with February the better month by 7 points if the dates can move. If they cannot, nothing here should stop you booking.

Every month in Invercargill

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