Weather in Adelaide in September

Prime time. If you get to pick your dates, September is the one. Highs average 18.6 °C, lows 8.6 °C, and rain falls on 9 days — nothing in the month is working against you.

September ranks 7 of 12 in Adelaide: past the worst of the year but short of March, which is the month to book if the dates are open.

Rain on 9 days, 1 of them heavy. Enough to need a plan B, not enough to need a plan around it. 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. Across the twenty years measured, the hottest September day reached 30.2 °C and the coldest night fell to 3 °C, and the wettest single day dropped 26 mm — roughly 55% of the month's rain in one day.

September is moderately variable: 11 mm in the driest year against 107 mm in the wettest, around an average of 47 mm. Roughly two Septembers in three land near that average, and the third does something else entirely.

Wind is light at 9.5 km/h, so the temperature on the page is close to the temperature on your skin, and humidity is unremarkable at 71%.

How September sits in the year

The month is on the way up: 2.8 °C warmer than August, and October adds another 3.5 °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

11.8 hours of daylight, gaining 1.1 hours across the month. That is between Adelaide's extremes of 14.5 and 9.8 hours, so days are long enough not to constrain the plan.

An inland climate

Despite being inland, the year stays fairly even: 23.5 °C between the year's warmest afternoons and coldest nights.

How busy it gets

Shoulder. The value months — prices ease off and you get the place closer to itself. September is the value pick for Adelaide: it scores within 13 points of March without carrying March's prices.

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

September in Adelaide versus nearby

If Adelaide is one option among several, the nearby comparison is worth making. Gawler is close enough to be a coin toss — within a degree on temperature, 1 day less rain. Whyalla is a better bet in September — 2.6 °C warmer, 4 days less rain.

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

Every month in Adelaide

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