We did a night at the zoo in April - the weather was starting to get cold but it was still good fun to do. The experience wasn't as good as I thought it was going to be (the pictures show you sitting down having drinks with the Sydney Harbour backdrop - that didn't happen). It was still fun though especially for Oscar and Evie - although we did go to bed at 8pm not the 10/11pm that it was supposed to be finished!
The highlight was probably getting to feed the giraffes first thing in the morning -
A fun local experience although expensive.