Daytime high temperatures on Maui range from about 78 degrees in the wintertime to about 88 degrees in the summertime. This slight variation in temperature during the year is due to Hawaii's proximity to the equator and the cooling effect of the surrounding ocean during the summer.

Because the weather on the islands is usually very mild and pleasant, there is really no bad time to visit. The weather can be rainy and wet from the last few months of the year until March, but the rain is not drastic enough for any vacationers to avoid the island during particular months. Also, if it does rain, it can do so in specific locations and also be over quickly. The specific locations are the windward sides of the island, which includes the road to Hana. There is also a "wrap around" effect as the wind blows the rain around the northwest end of Maui.

The majority of the resorts are along the leeward side of the island. This means any showers, blown in on the tradewinds, have dropped their moisture along the windward side. It has been found that does not do the best job in predicting weather along the south and west sides of the island. There can be a winter storm - called a kona low when the wind comes from the southwest - which will blow in off the ocean with rains for the resort towns. This usually happens about one time during the winter months.  

The water that surrounds the Hawaiian Islands, including Maui, is warm all year. In the winter, water temperature averages 75° and in the summer 82°. Surfing, which is one of the most popular sports on Maui, can be practiced all year long but the waves are bigger on the north shores during the winter months and south shores during the summer months.

The weather is more affected by what area you are staying in, more than when you choose to go. There are many micro climates on Maui. If it is raining where you are, move a few miles away, and you can find better weather there.

When to go 

Whale season starts in mid-December and generally is over by the end of April. February is the peak of the season which provides visitors with the ability to see many pods of whales in the ocean from various tour operators based in Lahaina, Ma'alaea and Kihei. You can even see them breach out of the water from viewpoints on the Pali highway (road between Lahaina and Ma'alaea). Stopping along this road is not recommended except at a very few pull-outs as the emergency lane is narrow.

The Maui Weather site shows Lahaina's monthly average high, low and ocean water temperatures. Historic rainfall and temperature charts are also available for many Maui towns.

Beyond the weather, another deciding factor on when to go is what time in the tourism calendar your vacation is. Maui  has a pretty consistent ebb and flow as far as how many tourist are on the island at a particular time. The busiest times are when school students have vacation. This allows families to come to the island together and many take advantage of that time frame. Times like summer vacations, spring break, Thanksgiving and Christmas are the most affected. On the other hand, the times right before or after these dates are usually quiet. This makes getting reservations for activities and accommodations easier.  

Mosquitos are common on the Hana side in late August, especially in lawn areas. Just be sure to keep doors closed. Generally speaking mosquito repellent is not needed, with mosquitoes only being a problem at night.