Hey Decoy, not sure if you have already left but we just got back to ChCh from our trip. FYI here are the conditions that we had:
We walked in from Raspberry Flat a week ago via French Ridge and the Quarterdeck in the soft snow (both above and below our feet - up to waist deep - snow from 700m altitude and continuing to fall) and crossed the Bonar Glacier to Colin Todd in full whiteout and occasional snow. Two 10 hour days through soft snow were very tiring.
A couple of rest days later (one good weather but knackered and one bad weather) and the forecast was looking good despite the recent snow and a day of sun and a highish freezing level of 2600m - "narrow ridge of high pressure followed by a brief shower in the afternoon falling as snow to 2400m".
We set off at 1:20 am to beat the afternoon shower and ended up getting to the summit via the Ramp in a snowstorm which started at about 9 am (about the time we summited) and descending back down the ramp through the snowstorm and near whiteout taking 16 hours round trip to get back to the hut with snow to 1700m. So not "brief", "afternoon" or "2400m".
Pitching the ramp and top third of the ridge then pitching/simulclimbing all the way back down because of the wind and quality of ice/riming. Snow/ice the whole way to the summit from the hut including the rock step, with substantial riming of the ridge. The ramp had actually firmed up during the day except of the 5 cm of fresh powder over the top.
Pretty unnerving in storm but we held it together. Zero view from the summit. Climbed Rolling Pin the next day in stunning weather to get some idea of the view.
Walked out in the rain and driving wind via Bevan col yesterday which thankfully had the waterfalls and guts filled in with av debris.
Full winter Mt Aspiring trip in late Spring!!
NW buttress route covered in snow but a group did go up that way.