Two seasons, one clear winner
The Maldives has a dry season and a wet season. The dry season (December to April) is when most tourists visit. The wet season (May to November) brings rain, rougher seas, and lower prices. Here is the detailed breakdown.
Dry season (December to April)
December to April is the classic Maldives season — calm seas, excellent visibility for diving and snorkeling (20-30m), minimal rain, consistent sunshine. December and January are peak months with the highest prices. February to April is slightly quieter with marginally lower rates. The water temperature is 28-30°C year-round regardless of season.
Wet season (May to November)
The southwest monsoon brings increased rainfall and sometimes rough seas from May onwards, peaking in June-July. This does not mean it rains all day — typically short heavy afternoon showers rather than continuous rain. Diving visibility drops somewhat (15-20m rather than 25-30m) but manta ray season coincides with this period (May-November in the south atolls). Prices are 20-40% lower. July and August see European school holiday travelers pushing prices back up slightly.
My recommendation
February to April for the best weather and not peak pricing. May for the best value in dry-ish weather. November for manta rays on local islands at reasonable prices. Avoid late December and early January unless you are booking a year ahead and have a resort budget.