Weather in Invercargill in August

A hard month. August is a hard month in Invercargill, and worth planning around. Highs sit at 10.4 °C and the day is short; this is an indoors-with-excursions month, not an outdoors-all-day one.

August ranks 10 of 12 — near the bottom of Invercargill's year. February is the month that works, and the swing between the two is 31 points, which is a different holiday rather than a slightly better one.

This is persistent light rain rather than storms: 18 wet days but only 2 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 10.4 °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 — 3.9 °C between the overnight low and the afternoon high. Across the twenty years measured, the hottest August day reached 16.1 °C and the coldest night fell to 1.5 °C, and the wettest single day dropped 37 mm — roughly 42% of the month's rain in one day.

August is statistically steady but not small: the year-to-year variation is modest in relative terms, yet the wettest August on record still delivered 139 mm against 41 mm in the driest. In a month this wet, even a tame spread is a lot of rain in absolute terms — the 88 mm average is a reasonable planning figure, not a promise.

Wind is light at 14.5 km/h, so the temperature on the page is close to the temperature on your skin, and humidity runs at 84%, which at 10.4 °C means damp rather than muggy — the kind of cold that gets into a coat and stays there.

How August sits in the year

Temperatures hold steady either side: 9.5 °C in July, 10.4 here, 11.8 in September. Nothing about the timing within the month matters much.

Daylight in August

10.1 hours of daylight, gaining 1.4 hours across the month. That is between Invercargill's extremes of 15.8 and 8.6 hours, so days are long enough not to constrain the plan.

Sea temperature

The sea sits at about 9.9 °C in August — 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

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.

August in Invercargill versus nearby

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

So: August is a compromise. February is 25 points better and is what Invercargill 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 Invercargill

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