Weather in Mackay in September

Prime time. If you get to pick your dates, September is the one. Highs average 23.7 °C, lows 20.9 °C, and rain falls on 3 days — nothing in the month is working against you.

September ranks 2 of 12 in Mackay. Only August scores clearly higher, and the difference is small enough to be settled by price rather than weather.

Rain falls on only 3 days, so an itinerary with no wet-weather fallback is a reasonable risk. 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 September reaches 30 °C; the day barely swings — 2.8 °C between the overnight low and the afternoon high. Across the twenty years measured, the hottest September day reached 28.1 °C and the coldest night fell to 15.6 °C, and the wettest single day dropped 79 mm — roughly 376% of the month's rain in one day.

This is the volatile part. September rainfall has ranged from 0 mm to 154 mm across the twenty years measured — a 154 mm spread around an average of 21 mm. The average is real but almost no individual September looks like it, so treat the figure as the middle of a wide range rather than a forecast.

Wind is light at 13.6 km/h, so the temperature on the page is close to the temperature on your skin, and humidity is unremarkable at 74%.

How September sits in the year

The month is on the way up: 1.8 °C warmer than August, and October adds another 1.7 °C. Late in the month feels noticeably different from the start of it, which is worth knowing if the trip is short.

Daylight in September

11.9 hours of daylight, gaining 0.6 hours across the month. That is between Mackay's extremes of 13.4 and 10.9 hours, so days are long enough not to constrain the plan.

Sea temperature

The sea sits at about 23.8 °C in September — comfortable for a proper swim. The sea peaks at 28.5 °C in February and bottoms out at 23 °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, November is the trade worth considering — 12 points weaker on weather, and materially quieter.

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

September in Mackay versus nearby

If Mackay is one option among several, the nearby comparison is worth making. Airlie Beach is close enough to be a coin toss — 2.6 °C warmer, the same number of rain days. Rockhampton is the weaker option in September — 4.7 °C warmer, 1 day more rain.

So: September is effectively as good as it gets here — 0 points behind August, which is inside the margin where the weather stops being the deciding factor and price starts being it.

Every month in Mackay

See all twelve months in Mackay, or where else to go in September.