Do I Need a Jacket Day has arrived earlier than expected this year.
It's much warmer than usual on the first day of spring - but the Bureau of Meteorology is warning that next week will be chillier again.
With a maximum of 22 degrees in Canberra on Wednesday, the unseasonably high temperatures are set to continue until Saturday.
Thursday will be slightly warmer, but then it's back down to 16 degrees on the weekend.
This spring is also forecast to be wetter than average, but not much hotter or colder.
The bureau doesn't expect temperatures to be that out of the ordinary, except that maximums will be a little bit lower than usual while minimums are forecast to be a little bit higher than usual.
In the three months of spring, rain is expected to be heavier than usual, with a good chance of it being substantially heavier. A usual spring would see 170 millimeters over September, October and November, but the bureau reckons there's a reasonable possibility of 200 millimetres or even 250.
But the warm opening day of spring is what everyone notices.
"We are running six or seven degrees above average at the moment, but then it all cools down from Saturday," forecaster Hugh McDowell said.
The warmth has arrived because a ridge of high-pressure air is drawing in warmer air from central Australia and the north, but that will change as the week progresses so colder air from the south is drawn in instead.
We can thank (or curse) the Indian Ocean Dipole for the expected wetter spring.
Like the more famous El Nino over the Pacific, different temperatures of the ocean result in different weather patterns in Australia.
Waters in the eastern Indian Ocean (near Indonesia) are expected to be warmer than normal, and those in the western Indian Ocean (near Africa) are expected to be cooler than normal.
This causes more moisture-filled air to flow towards Australia.
And that means more moisture-filled air over Australia - in other words, rain.
The heavy rain of winter has led to lusher grass around the ACT so the territory government's 73 lawn-mowers are being deployed.
"The focus for our crews will be mowing at roadside intersections to keep grass maintained to a safe level and prevent any line-of-sight issues for drivers," Transport and City Services Minister Chris Steel said.
"We will also be mowing the irrigated parks around town at staggered times and ACT Government sportsgrounds, which are seeing extra traffic at the moment with more Canberrans doing individual exercise outside.
"We ask for the community's understanding and patience as our crews work to mow priority areas across the city while also complying with current health directions."
Lawn-mowers have GPS trackers so a central data-base of where they've been working can be drawn up.
"When the mowing program is in full operation after lockdown, this information will be used to populate a live mowing map that will show where crews have been and where they are intending to mow in the coming weeks," the ACT Government said.
