Five teams were set to be in action at Winton today with Brad Jones Racing, Tickford Racing and Walkinshaw Andretti United all planning full test days with both of their cars.
Erebus Motorsport was set to run an evaluation day while Grove Racing planned a rookie day for Matt Payne.
However wet weather has curtailed the day after limited running in the morning.
Teams are able to abandon a test day within two hours of their first lap, or before 11am local time, whichever comes first, without eating into their limited allocation.
That makes the cancellation particularly important for BJR, Tickford and WAU as those are the teams that were set to use one of their two remaining full test days.
The weather has already affected Tickford's plans, the Ford squad having called off rookie tests for Thomas Randle and Declan Fraser on Tuesday.
The weather could be a free kick for the Queensland-based teams which are set to test at Queensland Raceway tomorrow.
The forecast for Ipswich tomorrow is mostly sunny with top of 26 degrees.
