http://www.thredbo.com.au/weather-and-c ... e-cams.asp
Check the conditions before you go. A couple of days can make a big difference. It's often quite windy up high (above 1600m) but the main danger is getting lost in bad weather in all that flat terrain. Take a GPS that you've practiced using. Winds around genuine 40 knots (70 km/h) are not uncommon, even if it's sunny, though the people at their desks down in the resort have no clue
about anything beyond the chairlifts.
In good weather it's an easy trip. I usually do it once or twice each winter, either on snowshoes or skis. Allow a couple of hours each way to enjoy the scenery. It's just walking, no climbing, but the middle section can get quite hard and icy, scoured by winds - slippery to walk on sometimes.
Note that if you don't have a 4WD then you need to hire chains in Jindabyne - the police set up roadblocks to check and fine those without them. Chains + Nat Park entry + chairlift(!) + breakfast pies & coffee = $100 to climb Kozi. And that's in addition to getting to Jindabyne, accomodation, pizza, beer and 2am rum shouts at the Brumby Bar.