Labour weekend in New Zealand is the traditional time to get your tomato plants in the ground, supposedly the worst of the vagaries of spring weather are past and will be kind to them from now on. I spent the morning planting mine, inside the greenhouse because I know from experience that our climate is too fickle to trust! As usual I have lots of different varieties and have crammed too many into the space I have, so will have an unmanageable thicket all too soon LOL
oops - mine are still waiting to be planted - I agree the weather is a little too fickle but my glasshouse has lost a few panes of glass - more like a wind tunnel now! good luck with the growth!
Those home grow tomatoes are so tasty, and you are right, too risky to plant them out now.