I ventured to Fiji (4 Days) at end of January last year and found the weather hot but also very humid.
Stayed at Fiji Hilton in a 1 bedroom beach front and thought it was great.
Ended up drinking lots of Vonu Lager
Fiji Premium was good, but tried nothing else once I had the Vonu.
When I went they had recently had floods in Nadi from memory and once I left not long after there were floods again.
I then took the kids to Fiji in September (9 days) staying at the Radisson and the weather was very good every day except one where it rained on and off all day.
Heading there again in late April and going to venture out to Blue Lagoon Beach Resort for 5 nights either side of a Denarau stay at the Westin.
The pictures on their Facebook page from Christmas / New Years look like they had near perfect weather, amazing after the Cyclone had only recently passed.
I believe the mainland (well 2 larger Islands) experience more rain than the outer Islands.
If you like diving then by all reports Yasawa and Mamanucas Island group have fantastic dive sites, thinking of giving it a go when we head over (Jaws is on TV tonight and I am purposely avoiding having the TV on
)