Weather in Sydney in January

The month to avoid. Of the twelve, January is the one to avoid. Highs sit at -0.6 °C and the day is short; this is an indoors-with-excursions month, not an outdoors-all-day one.

January ranks 12 of 12 — near the bottom of Sydney's year. July is the month that works, and the swing between the two is 65 points, which is a different holiday rather than a slightly better one.

Rain on 15 days, 4 of them heavy. Enough to need a plan B, not enough to need a plan around it. Layers, and a genuinely waterproof outer — at -0.6 °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: 29 nights drop below freezing, so anything left outside stays frozen; the day barely swings — 5.7 °C between the overnight low and the afternoon high. Across the twenty years measured, the hottest January day reached 9.4 °C and the coldest night fell to -17.5 °C, and the wettest single day dropped 46 mm — roughly 42% of the month's rain in one day.

January is statistically steady but not small: the year-to-year variation is modest in relative terms, yet the wettest January on record still delivered 165 mm against 40 mm in the driest. In a month this wet, even a tame spread is a lot of rain in absolute terms — the 109 mm average is a reasonable planning figure, not a promise.

Wind sits around 24.4 km/h — a steady breeze rather than a nuisance, and welcome on the warmer days, and humidity runs at 87%, which at -0.6 °C means damp rather than muggy — the kind of cold that gets into a coat and stays there.

How January sits in the year

Temperatures hold steady either side: 2.7 °C in December, -0.6 here, -1.5 in February. Nothing about the timing within the month matters much.

Daylight in January

January sits at the dark end of Sydney's year — 9 hours of daylight against 15.7 at midsummer, gaining 0.9 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 1.9 °C in January — too cold to swim without a wetsuit. The sea peaks at 18.4 °C in August and bottoms out at -0.2 °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.

January in Sydney versus nearby

If Sydney is one option among several, the nearby comparison is worth making. Halifax is close enough to be a coin toss — within a degree on temperature, 2 days less rain. Moncton is close enough to be a coin toss — 3.1 °C cooler, 3 days less rain.

So: January is a compromise. July is 65 points better and is what Sydney 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 Sydney

See all twelve months in Sydney, or where else to go in January.