185skywagon,
Good question. The highest peak (Mt Wilhelm) is around 14 700' from memory. Plenty of other peaks in the 10-14 000' range. On these highest peaks it is visibly 'alpine' terrain which is essentially terrain with no trees. That is on the occasional exceptionally good mornings when you can actually see the peaks before they get covered in cloud! I don't believe snow is a regular weather feature even at those high altitudes. However I have had one PNG veteran tell me that many years ago he did once sight snow on one of the peaks (I think it was Mt Gilluwe near Mt Hagan?).