With average temperatures ranging between 70 and 85 degrees throughout the year, there’s hardly ever a bad weather day on Kauai. Just be ready for the occasional refreshing rain.
Kauai has several weather zones. The more arid (and warmer) western region (Waimea) receives significantly less rainfall than the lush interior rain forests and mountains that receive up to 450 inches per year. The south side (Poipu) generally receives the most sunshine while the North Shore (Hanalei) receives more rain. The eastern coast of Kauai (Kapaa and Lihue) receives a good amount of sunshine with occasional rains.
If you’re seeking sun then it’s best to book your accommodations in Poipu. North Shore stays require flexibility as it can rain for days. If that’s the case, head south to Kapaa or Poipu.
Kauai is known as the “Garden Island” because it rains often. Rain can come at a moment’s notice anywhere on the island so be prepared with appropriate gear and clothing or alternate plans.
Kauai has two seasons – summer and winter – with the winter months (November through April) averaging more rainfall than the summer months, when rain showers are more brief.
At Mt. Waialeale, with an elevation of over 5,000 feet, it rains almost 365 days per year. So count on at least some rain when traveling to this part of the island (Koke’e State Park, Kalalau Lookout), and perhaps pack a windbreaker as the temperatures are cooler at the higher elevations.
If you’re hiking, be prepared for a lot of mud. Count yourself lucky if the trail is dry.
Humidity can also be a factor and many visitors notice it as soon as they get off the airplane. Drink plenty of water during your time on Kauai.
Very rarely, hurricanes may be a factor in the late summer months but the island has taken only a few direct hits in modern times.
The weather can certainly have an effect on your Kauai vacation. Winter months see more cancellations (or diversions) of Na Pali Coast boat tours due to rough seas. Also in the winter months, the Hanalei River is more likely to flood, temporarily cutting off access to Kauai’s North Shore for 24-48 hours. This closure happens very infrequently, but it does happen. Nevertheless, rough seas or flooding can happen at any time of the year and there is really no way to plan around the weather.
The sun is stronger here on Kauai than on the mainland and non-tropical locations. Sunblock and sun-protective clothing are recommended.
Overall, Kauai weather is what is to expected from a tropical island – with warm weather and refreshing rains in an island paradise.