A very pleasant day trip using the round trip. Good weather; but even in good weather at this time of the year you need to be well-prepared with warm and weather-proof clothes. We wore jackets but didn't take, or need, weatherproof pants - which I would say, in passing, are essential for any multi-day tramps in the Arthur's Pass region.
Photos below show the Avalanche Peak summit ridge; a kea on the summit ridge; and a nearby hanging glacier (sorry, I forget on which mountain) seen from the summit.