how would you know ?
Because it just doesn't, nor has it ever happened. Unless a game has ever been played at Thredbo Top Station at almost 2000 mtrs asl, or Perisher Valley which would be the only two places where that temp could ever be conceivable at the time of night. Maybe some Victorian ski resorts as well like Hotham or Falls Creek.
Canberra at -6 at 8 pm? It has NEVER HAPPENED.
Even apparent temps (which aren't real temps) would rarely to get to that.
Someone else claimed it. I say it isn't remotely possible.
How about you prove me wrong?
I can categorically confirm that Canberra have never played in a temp of -6. Ever.
They have certainly played in temps hovering just above or maybe just below zero on the clearest of nights at the beginning or end of matches, but never during a game has the ground temperature been as low as -6.
Canberra has 5 months with record low mins being below -6. None of them would have occurred during an NRL match.