Do you need to know, when is the best time to go to Bali? Then you should take a look here, what weather you can expect there during the year.
Bali is part of Indonesia. The climate of Indonesia is tropical. You can expect hot and humid weather, but more moderate weather in highlands. Temperatures remain fairly constant throughout the year, they are higher at the coast and a little bit lower in the inland.
When speaking about the usual weather in this area, the information is relevant for example for these popular places: Amed, Bedugul, Bukit Peninsula, Candidasa, Canggu, Central Bali, Denpasar, East Bali, Gilimanuk, Jimbaran, Kintamani, Klungkung, Kuta, Legian, Lovina, Medewi, Mount Agung, Negara, North Bali, Nusa Dua, Nusa Lembongan, Nusa Penida, Padang Bai, Pemuteran, Sanur, Seminyak, Singaraja, South Bali, Southeastern Islands, Tabanan, Tanah Lot, Tirta Gangga, Ubud, West Bali, West Bali National Park.
Let's look now what weather you can expect in the area around Denpasar and in many other cities. The warmest month here is March, the average maximum temperature is 34.6 ℃ (94.28 ℉). The average minimum temperature in this month is 24 ℃ (75.2 ℉). The coldest month here is August, the average maximum temperature is 30 ℃ (86 ℉). The average minimum temperature in this month is 22.3 ℃ (72.14 ℉). The most rainy month here is January, the average number of rainy days is 26.4. The least rainy month here is August, the average number of rainy days is 4. 
When travelling around Bali, always consider the altitude of the the place as well. We should remind you, that the highest point in Indonesia is Puncak Jaya (4884 m) and the lowest point is Indian Ocean (0 m). So there are huge differences in altitudes in this country and the weather is very different in them therefore. Keep in mind, that the temperature usually decreases by 1.2 - 1.9 ℃ (2.2 - 3.5 ℉) per 200 m (656 ft), depending on the other conditions. (And we should add, that in the very special condition named thermal inversion even the temperature may be higher in higher altitudes.)
Typical (usual) weather in Bali in January is this: The average highest temperature in Bali in January is 32.6 ℃ (90.68 ℉). The average lowest temperature is 24.7 ℃ (76.46 ℉). At the beginning of January you can expect higher temperatures, the average highest temperature is around 32.7 ℃ (90.86 ℉). At the end of January you can expect higher temperatures, the average highest temperature is around 33 ℃ (91.4 ℉). The average number of rainy days in January is 26.4. The average rainfall is 337.8 mm (look here, what this number means). When planning your travel, please, keep in mind, that actual weather may differ from these average values. The length of the day at the beginning of this month is approximately 12:37 (hours and minutes), in the middle of the month 12:34 and at the end of the month 12:29.These numbers above are valid primarily for the capital and the area around it. It is important to say, that the weather may differ significantly in different altitudes, especially in mountains.Typical (usual) weather in Bali in February is this: The average highest temperature in Bali in February is 33.4 ℃ (92.12 ℉). The average lowest temperature is 24.7 ℃ (76.46 ℉). At the beginning of February you can expect lower temperatures, the average highest temperature is around 33 ℃ (91.4 ℉). At the end of February you can expect higher temperatures, the average highest temperature is around 34 ℃ (93.2 ℉). The average number of rainy days in February is 22.5. The average rainfall is 271 mm (look here, what this number means). When planning your travel, please, keep in mind, that actual weather may differ from these average values. The length of the day at the beginning of this month is approximately 12:29 (hours and minutes), in the middle of the month 12:22 and at the end of the month 12:15.These numbers above are valid primarily for the capital and the area around it. It is important to say, that the weather may differ significantly in different altitudes, especially in mountains.Typical (usual) weather in Bali in March is this: The average highest temperature in Bali in March is 34.6 ℃ (94.28 ℉). The average lowest temperature is 24 ℃ (75.2 ℉). At the beginning of March you can expect lower temperatures, the average highest temperature is around 34 ℃ (93.2 ℉). At the end of March you can expect lower temperatures, the average highest temperature is around 34.4 ℃ (93.92 ℉). The average number of rainy days in March is 20.2. The average rainfall is 237.2 mm (look here, what this number means). When planning your travel, please, keep in mind, that actual weather may differ from these average values. The length of the day at the beginning of this month is approximately 12:15 (hours and minutes), in the middle of the month 12:08 and at the end of the month 12:01.These numbers above are valid primarily for the capital and the area around it. It is important to say, that the weather may differ significantly in different altitudes, especially in mountains.Typical (usual) weather in Bali in April is this: The average highest temperature in Bali in April is 34.2 ℃ (93.56 ℉). The average lowest temperature is 25.3 ℃ (77.54 ℉). At the beginning of April you can expect higher temperatures, the average highest temperature is around 34.4 ℃ (93.92 ℉). At the end of April you can expect lower temperatures, the average highest temperature is around 33.85 ℃ (92.93 ℉). The average number of rainy days in April is 9.1. The average rainfall is 88.7 mm (look here, what this number means). When planning your travel, please, keep in mind, that actual weather may differ from these average values. The length of the day at the beginning of this month is approximately 12:01 (hours and minutes), in the middle of the month 11:54 and at the end of the month 11:48.These numbers above are valid primarily for the capital and the area around it. It is important to say, that the weather may differ significantly in different altitudes, especially in mountains.Typical (usual) weather in Bali in May is this: The average highest temperature in Bali in May is 33.5 ℃ (92.3 ℉). The average lowest temperature is 24.3 ℃ (75.74 ℉). At the beginning of May you can expect higher temperatures, the average highest temperature is around 33.85 ℃ (92.93 ℉). At the end of May you can expect lower temperatures, the average highest temperature is around 32.3 ℃ (90.14 ℉). The average number of rainy days in May is 8.1. The average rainfall is 92.9 mm (look here, what this number means). When planning your travel, please, keep in mind, that actual weather may differ from these average values. The length of the day at the beginning of this month is approximately 11:48 (hours and minutes), in the middle of the month 11:43 and at the end of the month 11:39.These numbers above are valid primarily for the capital and the area around it. It is important to say, that the weather may differ significantly in different altitudes, especially in mountains.Typical (usual) weather in Bali in June is this: The average highest temperature in Bali in June is 31.1 ℃ (87.98 ℉). The average lowest temperature is 23.8 ℃ (74.84 ℉). At the beginning of June you can expect higher temperatures, the average highest temperature is around 32.3 ℃ (90.14 ℉). At the end of June you can expect lower temperatures, the average highest temperature is around 30.8 ℃ (87.44 ℉). The average number of rainy days in June is 6. The average rainfall is 53.4 mm (look here, what this number means). When planning your travel, please, keep in mind, that actual weather may differ from these average values. The length of the day at the beginning of this month is approximately 11:39 (hours and minutes), in the middle of the month 11:37 and at the end of the month 11:37.These numbers above are valid primarily for the capital and the area around it. It is important to say, that the weather may differ significantly in different altitudes, especially in mountains.Typical (usual) weather in Bali in July is this: The average highest temperature in Bali in July is 30.5 ℃ (86.9 ℉). The average lowest temperature is 22.9 ℃ (73.22 ℉). At the beginning of July you can expect higher temperatures, the average highest temperature is around 30.8 ℃ (87.44 ℉). At the end of July you can expect lower temperatures, the average highest temperature is around 30.25 ℃ (86.45 ℉). The average number of rainy days in July is 4.1. The average rainfall is 54.1 mm (look here, what this number means). When planning your travel, please, keep in mind, that actual weather may differ from these average values. The length of the day at the beginning of this month is approximately 11:37 (hours and minutes), in the middle of the month 11:39 and at the end of the month 11:43.These numbers above are valid primarily for the capital and the area around it. It is important to say, that the weather may differ significantly in different altitudes, especially in mountains.Typical (usual) weather in Bali in August is this: The average highest temperature in Bali in August is 30 ℃ (86 ℉). The average lowest temperature is 22.3 ℃ (72.14 ℉). At the beginning of August you can expect higher temperatures, the average highest temperature is around 30.25 ℃ (86.45 ℉). At the end of August you can expect higher temperatures, the average highest temperature is around 31.05 ℃ (87.89 ℉). The average number of rainy days in August is 4. The average rainfall is 25.3 mm (look here, what this number means). When planning your travel, please, keep in mind, that actual weather may differ from these average values. The length of the day at the beginning of this month is approximately 11:43 (hours and minutes), in the middle of the month 11:48 and at the end of the month 11:54.These numbers above are valid primarily for the capital and the area around it. It is important to say, that the weather may differ significantly in different altitudes, especially in mountains.Typical (usual) weather in Bali in September is this: The average highest temperature in Bali in September is 32.1 ℃ (89.78 ℉). The average lowest temperature is 22.5 ℃ (72.5 ℉). At the beginning of September you can expect lower temperatures, the average highest temperature is around 31.05 ℃ (87.89 ℉). At the end of September you can expect higher temperatures, the average highest temperature is around 32.55 ℃ (90.59 ℉). The average number of rainy days in September is 7.8. The average rainfall is 47 mm (look here, what this number means). When planning your travel, please, keep in mind, that actual weather may differ from these average values. The length of the day at the beginning of this month is approximately 11:54 (hours and minutes), in the middle of the month 12:01 and at the end of the month 12:08.These numbers above are valid primarily for the capital and the area around it. It is important to say, that the weather may differ significantly in different altitudes, especially in mountains.Typical (usual) weather in Bali in October is this: The average highest temperature in Bali in October is 33 ℃ (91.4 ℉). The average lowest temperature is 24 ℃ (75.2 ℉). At the beginning of October you can expect lower temperatures, the average highest temperature is around 32.55 ℃ (90.59 ℉). At the end of October you can expect lower temperatures, the average highest temperature is around 32.75 ℃ (90.95 ℉). The average number of rainy days in October is 12.1. The average rainfall is 63.5 mm (look here, what this number means). When planning your travel, please, keep in mind, that actual weather may differ from these average values. The length of the day at the beginning of this month is approximately 12:08 (hours and minutes), in the middle of the month 12:15 and at the end of the month 12:22.These numbers above are valid primarily for the capital and the area around it. It is important to say, that the weather may differ significantly in different altitudes, especially in mountains.Typical (usual) weather in Bali in November is this: The average highest temperature in Bali in November is 32.5 ℃ (90.5 ℉). The average lowest temperature is 24.1 ℃ (75.38 ℉). At the beginning of November you can expect higher temperatures, the average highest temperature is around 32.75 ℃ (90.95 ℉). At the end of November you can expect higher temperatures, the average highest temperature is around 32.65 ℃ (90.77 ℉). The average number of rainy days in November is 16. The average rainfall is 180.3 mm (look here, what this number means). When planning your travel, please, keep in mind, that actual weather may differ from these average values. The length of the day at the beginning of this month is approximately 12:22 (hours and minutes), in the middle of the month 12:29 and at the end of the month 12:33.These numbers above are valid primarily for the capital and the area around it. It is important to say, that the weather may differ significantly in different altitudes, especially in mountains.Typical (usual) weather in Bali in December is this: The average highest temperature in Bali in December is 32.8 ℃ (91.04 ℉). The average lowest temperature is 23.2 ℃ (73.76 ℉). At the beginning of December you can expect lower temperatures, the average highest temperature is around 32.65 ℃ (90.77 ℉). At the end of December you can expect lower temperatures, the average highest temperature is around 32.7 ℃ (90.86 ℉). The average number of rainy days in December is 22.2. The average rainfall is 274.1 mm (look here, what this number means). When planning your travel, please, keep in mind, that actual weather may differ from these average values. The length of the day at the beginning of this month is approximately 12:33 (hours and minutes), in the middle of the month 12:36 and at the end of the month 12:37.These numbers above are valid primarily for the capital and the area around it. It is important to say, that the weather may differ significantly in different altitudes, especially in mountains.