The dry season runs from December to April and is the most comfortable time to visit most of Honduras. Temperatures are warm (low 30s Celsius on the coast, cooler in the highlands), humidity is lower, and roads are passable. January through March are the peak months — expect more company at the popular sites and slightly higher prices.
The wet season runs May through November. In much of the country rain comes in the form of afternoon showers rather than all-day downpours, so mornings are often clear. The north coast and La Mosquitia receive more consistent rainfall year-round. Hurricane season runs August through October and occasionally brings serious storms; October 1998's Hurricane Mitch caused catastrophic damage to the country. Check conditions if you're visiting during this period.
The Bay Islands have a slightly different pattern: their heaviest rains come from October through January, making January–March the driest and clearest months for diving.
The mountains — including the area around Copán and the western highlands — are cooler year-round. At altitude, even the dry-season evenings can be cold.
For budget travelers, the shoulder months of May and November offer the lowest prices and thinner crowds. The weather is a gamble, but many travelers find it worth it.