Bali has a tropical climate, with warm, balmy, consistent temperatures. The mercury seldom leaves the 80- to 85-degree range year-round. Up in the mountains, it can get slightly chillier, but rarely colder than the mid-60s. The sunlight is consistent throughout the year, too, with 12 hours a day in both winter and summer.
The bad news, and the biggest factor in planning a trip to Bali, is the rain. The island's wet season is humid and really damp, with precipitation usually daily. It stretches from November to March, but the worst of it falls between December and January, with an average of 13 inches. Sudden rain showers can flood the rivers, making travel nearly impossible at times.
The Nyepi festival falls right at the end of the rainy season. Every March, a day of silence is taken, and anything that plays against that is restricted: no working, no talking, no eating.
The dry season, which lasts from April to October, is much more pleasant and a lot less humid. This period is also considered high tourist season, and hotels sometimes charge higher rates.
If you want to come during Galungan, Bali’s most important festival, check before booking. It occurs every 210 days, lasting for ten days each time, and it’s believed that all Balinese gods will come down to earth to party with you.