Will it rain during my Hawaii vacation? (and other Hawaii rainfall questions answered)

In Hawaii, just like anywhere else in the world, rain can be very unpredictable. In this article, we want to address some frequently asked questions about rain in Hawaii.

1. I’m looking at the forecast and I see raindrops every day. How much rain will I actually experience?

Rainfall levels are different for each island and even within the microclimates of each island. For example the windward (north and east) sides of each island tend to get more rain than the leeward (south and west) sides of the islands. See the explanation of leeward and windward. If the weather is rainy on one side, the other side might be dry.

Chances are that if rain is in the forecast, the windward sides are going to get rain, while the leeward side might not get any rain at all. That’s the most prevalent weather pattern Hawaii, but it’s not always the case as the weather is literally dependent upon which way the wind is blowing.

There’s also a chance that rain falls while your sleeping as research shows that rain mostly falls over night rather than day time hours.

Finally, be sure that you are reading the forecast properly. If you see rain in the forecast there’s usually an estimated percentage — from 0% to 100% —  alongside the rain prediction. The lower the percentage, the less likely you might see rain — for example, a 10% chance is quite low. A higher percentage indicates a greater chance of rain. Even if you see a high percentage, that doesn’t necessarily mean that you’ll see rain the entire day. It only indicates that there is a high chance that rain might fall at some point in that 24-hour period.

Before our most recent trip to Kauai (the “wettest” of the Hawaiian Islands) the forecast showed overcast skies and more that 40% chance of rain every day. We experienced two, very brief passing showers during our seven-day visit. These showers lasted no longer than a few minutes. Then, the sun was out again. So, don’t panic when you see rain in the forecast as there’s a chance it won’t interfere with your plans at all.

2. I want to go to <insert Hawaiian island> in <insert month>. Will it rain then?

No one knows if there’ll be rain in specific areas in Hawaii weeks or months into the future. Even expert meteorologists have trouble accurately predicting the weather a day or two in advance. It’s simply impossible for any human to know. We don’t know.

You and I can only look at seasonal rainfall trends to try to make the best decisions that we can. Even then, it’s purely a guess. We recommend that you read our island specific weather guides that offer lots of rain-related weather advice. Here are the guides:

Oahu Weather Guide

Maui Weather Guide

Hawaii (Big) Island Weather Guide

Kauai Weather Guide

3. I’m looking at the rainfall chart for <insert Hawaiian island> for the month of <insert winter month> and it shows a lot of rain. Does that mean it rains all the time? 

No, it does not rain all the time. When you read the rainfall charts, make sure that you are putting the data in the right context. To get perspective, compare the average monthly rainfall levels in your city to the Hawaii rainfall levels. For example, we live in Raleigh, North Carolina. I searched the internet for “average monthly precipitation Raleigh, NC”. From the search results, I learned that July is our “rainiest” month with an average of 4.29 inches, which also happens to be comparable to some of the rainiest months in the Hawaiian Islands. Does 4.29 inches of precipitation mean that it rains all the time in Raleigh in July? No, it doesn’t! As I’m writing this article on a mid-July day, the weather is so sunny that I can’t even see a cloud in the sky. We’ve had plenty of sunny days this month. We’ve also had plenty of rain, higher than average actually, but the rain has mostly fallen during evening thundershowers, while the days have mostly been sunny.

When you look at the average rainfall for an island, particularly for a winter month, don’t panic if you see three or four or even five inches of rain. Though those numbers are higher than what you might find in Hawaii for a summer month, it is by no means an indicator that the weather is rainy the entire winter month. We’ve been to all the islands in the wetter, winter months. We enjoyed more sunny days by far than rainy days on every visit.

Remember that averages are simply averages. Your actual experience may not be average. There are so many variables that can change the weather – fronts, changes in wind direction and, though unlikely, but still possible, a hurricane.

4. I want to go to Hawaii but I’m afraid it will rain. What should I do?

First, we wouldn’t hesitate to go to Hawaii any time of year — even in the “rainier” months. Chances are that rain won’t interfere with plans. Though we’ve lost count of the number of times we’ve been to Hawaii, we estimate it’s been well more than 30 times. In all those visits, we’ve very, very rarely had to change our plans because of rain.

Second, hope for the best weather, but be prepared if it’s not ideal. In our packing guide, we recommend bringing quick-drying clothes and a breathable, rainproof jacket just in case you get caught in a passing rain shower. You can still comfortably be out enjoying Hawaii’s scenery.

As previously mentioned in the first section, each island has its dry side and its wet side. If we visit in the wetter months, we try to stay on the dryer sides. See this article with advice on where to stay in Hawaii to avoid rain.

Finally, it’s important to have a positive attitude no matter what weather you encounter. Enjoy all of your short time in Hawaii even if there’s rain. If you happen to have a rainy day, check out our suggestions for what to do on Oahu,  Maui and Kauai

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In closing, remember that rain has many benefits. Here are just a few to note:

• Rain is necessary to grow the delicious tropical fruit and other produce that we enjoy on our Hawaii vacations.
• Rain supplies the water for Hawaii’s spectacular waterfalls.
• After a passing shower, you usually get to enjoy one of Hawaii’s famous rainbows.