The dry season: from April to October
Bali lies in the southern hemisphere, so its seasons are reversed from those in France, but the climate is very different, with higher humidity and higher temperatures on average. The monsoon is a climatic phenomenon that mainly affects Asian countries. Winds blow from sea to land, or vice versa, from land to sea, carrying away accumulated humidity. In some years, the two seasons are offset by a month.
The dry season is dominated by southeast winds. The best time to visit Bali is undoubtedly June, when there aren't too many tourists, low humidity and little rainfall. But a dry season doesn't necessarily mean no rain. Rainfall is rarer and generally occurs at the end of the day and at night, leaving you all day to enjoy the beach, hiking and other activities that Bali has to offer.
Dry-season temperatures range from 24 to 32°C during the day. In the evening, they tend to drop more significantly than in the wet season. Sunscreen and headgear are a must, as the sun beats down hard: in just one hour, the skin can quickly become sunburnt! In August, the weather is dry, but it's coolest of all, which is relative for a Westerner: around 26°C.
The wet season: from November to March
The wet season is dominated by north-easterly winds. Avoid coming in January, as this is the most unfavorable month, combining intense rain and high temperatures (almost 25 days of rain and 245 mm of precipitation in December and January). During the rainy season, from November to March, showers are heavy, generally localized and humidity is high. So it's not impossible to have fine weather on the coasts, while the mountains and volcanoes are drenched. As this is the hot season, the atmosphere can be difficult to bear, and you'll need time to acclimatize. Nevertheless, there's always plenty of sunshine.
Throughout the year in Bali, it's impossible to draw up a precise picture of rainfall patterns. We've experienced wet seasons with no rain and infernal heat, and August in Ubud with daily rain and a light sweater. Generally speaking, rain is more frequent in the north than in the south of the island. Although rainy spells are rarely long, they can last for several days during the wet season, accompanied by thunderstorms. Temperatures of over 30°C are not uncommon.
Beware of temperature variations: think of the (small) wool
The north of Bali is crossed by a volcanic chain, the "Pacific Ring of Fire", where the famous Gunung Agung volcano (3,142 m), the highest on the island, is still active. In this region, the weather is cooler. If you plan to go there, warmer clothes (jacket, sweater, pants) and waterproof clothing (anorak, umbrella) are essential. It's these temperature variations we're talking about here, since the difference in temperature between the dry and wet seasons is around 2°C on average. In the evening, a little wool with a light outfit will not go amiss. For hiking and mountain climbing, don't forget to bring good walking shoes.
As for the water temperature, it remains ideal all year round, at around 29°C.
Cyclones in Bali?
The 2004 tsunami, which was the first to hit Indonesia following an earthquake measuring 9.1 on the Richter scale on December 26, had very little impact on Bali, which is fortunate given the scale of this natural disaster (almost 250,000 victims!). Nevertheless, earthquakes are likely to occur as the archipelago lies at the convergence of two tectonic plates. As for tropical cyclones, Bali's position close to the equator means that it is not in the direct path of cyclones, typhoons or storms. From January to April, the risk is highest. Generally unaffected, unlike its neighbors Java and the eastern Sunda Islands, these events bring intense winds and rain to Bali for several days at a time. In 2013, cyclone Narelle brought strong winds, intense rain, 5-meter-high waves and falling trees near Denpasar. In March 2019, tropical storm Savannah caused extensive damage near Buleleng.
