Hawaii’s weather stays pretty steady all year, but if you know the monthly quirks, you can dodge a few surprises on your trip. People often think the islands never change, but honestly, each month has its own thing going on with temperature, rainfall, and wind—stuff that can totally change your plans, whether you’re hitting the beach or heading out for a hike.
Hawaii really has just two seasons—a warmer, drier stretch from May to October and a cooler, wetter one from November to April. Temperatures usually hover somewhere between the mid-60s and upper 80s Fahrenheit. These seasonal swings affect rainfall, ocean moods, and just how comfy it feels to be outside.
The islands’ wild geography means you get crazy weather shifts in just a few miles, so knowing what to expect each month can help you plan better. Some windward slopes get dumped on with over 400 inches of rain a year, while leeward coasts barely see 20 inches. That kind of variety shapes everything—your travel moves, your outdoor fun, and even daily island life.
Understanding Hawaii’s Tropical Climate
Hawaii’s tropical climate keeps things warm all year, with only tiny changes in temperature—usually between 70°F and 85°F. Trade winds, shifting weather, and a bunch of microclimates give each island its own weather personality.
Role of Trade Winds
Trade winds blow in from the northeast and basically act like Hawaii’s natural AC. They keep things comfortable and shape the local weather in some pretty dramatic ways.
These winds push moist air up the windward mountains. As the air rises and cools, it dumps rain on the northeast sides. By the time the air crosses over to the leeward sides, it’s lost most of its moisture.
Wind Effects:
- Keep temperatures nice by constantly cooling things down
- Make windward sides wet and leeward sides dry
- Usually blow at 10-25 mph most days
- Help lower humidity along the coasts
If the trade winds disappear, Hawaii feels way hotter and stickier. When they’re blowing, even July and August feel good enough for just about any outdoor plan.
Seasonal Variation in Weather
Hawaii skips the usual four seasons. Instead, there’s the dry season from April to October and the wet season from November to March.
Seasonal Temperature Differences:
- Winter: averages 70°F – 80°F
- Summer: averages 76°F – 85°F
- Only about a 5-6 degree swing between seasons
Most of Hawaii’s rain falls during the wet season. December usually gets the most—somewhere between 6 and 12 inches in a lot of places. June tends to be the driest, barely getting an inch statewide.
The ocean cools off a little in winter, down to about 75°F, and warms up to around 80°F in summer. That small shift still changes the feel of the weather and how nice the water feels for swimming.
Microclimates Across the Islands
Each island packs in a bunch of different microclimates. Elevation, hills, and those trade winds make the weather flip fast, even if you drive just a few miles.
Coastal spots stay warm and pretty dry all year. But higher up, it gets cooler and a lot wetter. Once you get above 6,000 feet, winter temps can drop to 30°F.
Microclimate Examples:
- Waikiki Beach: Warm, dry, about 80°F
- Haleakala Summit: Cool and all over the place, 40-60°F
- Hilo: Wet, tropical, over 200 inches of rain a year
- Kona Coast: Dry and sunny, less than 20 inches of rain a year
Windward sides can see 100-400 inches of rain every year. Leeward sides? Sometimes less than 20 inches. Mount Waialeale on Kauai is famous for being one of the wettest places on the planet, with over 400 inches of rain.
These microclimates mean you can hit a desert, a rainforest, and even an alpine zone all in one day if you’re ambitious.
Average Monthly Temperatures in Hawaii
Hawaii keeps warm temps all year, usually somewhere between the low 60s and mid-80s Fahrenheit. It’s coolest from December through March, and hottest from July through September.
Temperature by Month Overview
Hawaii’s temperatures don’t really surprise you. February is usually the coldest, averaging around 63.5°F (17.5°C).
August is the warmest, with averages near 70.5°F (21.4°C). The whole year only swings about 7°F from coldest to hottest month.
Monthly Temperature Breakdown:
- Winter (Dec-Feb): 63-66°F average
- Spring (Mar-May): 66-72°F average
- Summer (Jun-Aug): 72-75°F average
- Fall (Sep-Nov): 68-72°F average
Temps usually hit their lowest just before sunrise. The warmest part of the day is early afternoon.
These slow changes make the weather feel pretty steady. Most places almost never see temps below 60°F or above 90°F.
Seasonal Temperature Differences
Hawaii really only has two seasons. The “cool” one goes from October to April, and the “warm” one runs May through September.
During the cool season, most places sit between 68°F and 80°F. January usually lands right in that range.
The warm season only bumps things up a little. Summer averages are between 75°F and 87°F in most spots.
Key Seasonal Patterns:
- Temps only vary about 15-20°F throughout the year
- Ocean stays warm enough for swimming any month
- Nights rarely dip below 65°F
- Daytime highs almost never hit 90°F at sea level
This mellow range is a big reason people visit Hawaii any time of year. The seasons change so gently, it’s almost hard to notice.
Temperature Variation Across Regions
Different parts of each island feel different, mostly because of elevation.
Honolulu barely changes all year. Highs usually land between 80-87°F, lows between 68-75°F.
Hilo feels a bit cooler, thanks to its windward spot. It usually runs 2-3°F cooler than Honolulu.
Go up into the mountains and it gets a lot colder. Above 3,000 feet, you can lose 20-30°F compared to the beach.
Regional Temperature Factors:
- Windward sides: Cooler, thanks to trade winds and clouds
- Leeward sides: Warmer, sunnier
- Coastal areas: Most stable temps of all
- Interior valleys: Sometimes warmer during the day
Trade winds do a lot to keep things comfortable everywhere. They really are Hawaii’s built-in air conditioning.
Monthly Rainfall Patterns in Hawaii
Rainfall in Hawaii jumps all over the place, depending on the month and where you are. The wettest stretch is November to March, while June through October stays driest. December usually gets the most rain, June the least.
Rainfall Patterns by Month
Rain in Hawaii follows some pretty clear patterns. The wet season is November through March, with December usually topping the charts for rainfall.
June is the driest month, almost everywhere. April to October is the dry season, and rain drops off a lot. March often sees a bump in rain compared to February, even after you factor in the extra days.
April and October are kind of in-between months. Spring dries out, fall starts to get wetter again. These patterns don’t change much from year to year, which makes planning easier.
Typical Monthly Rainfall Distribution:
- Wettest: December, January, February
- Moderate: March, April, October, November
- Driest: May, June, July, August, September
Regional Rainfall Differences
Rain can be wildly different depending on which side of the island you’re on. The windward (northeast) sides get way more rain than the leeward (southwest) areas.
Hilo, on the Big Island, gets drenched compared to Kona on the same island’s drier side. Honolulu’s airport weather matches Waikiki, while Oahu’s North Shore gets more rain than the south.
Maui’s weather splits up too. Kahului gets more rain than touristy Wailea and Lahaina. Hana, on the east side, is super wet because it’s windward.
Kauai has the same thing going on—North Shore is wet, Lihue airport is drier, and the South Shore barely gets any rain. Sometimes, places just a few miles apart see several inches of difference in a single month.
Impact of Wet and Dry Seasons
The wet season (November to March) means higher humidity and more showers, especially on windward sides. Rain usually comes in short, heavy bursts—not all-day downpours.
You can swim and do ocean stuff all year since the water stays warm. But hiking on the windward sides gets tricky in the wet months—muddy trails and slippery rocks are no joke.
The dry season is perfect for outdoor adventures and beach days. Resorts on leeward sides keep nice weather even when it’s rainy elsewhere. If you want to dodge showers, just pick lodging on the dry side.
Seasonal rain changes the landscape—wet months refill streams and reservoirs, while dry months stress native plants and can even bring fire risk.
Key Weather Features of Major Hawaiian Locations
Every major Hawaiian spot has its own weather quirks, shaped by the land and the height above sea level. Honolulu stays warm and dry, Hilo gets soaked, and the mountains can be freezing.
Honolulu: Weather Details
Honolulu’s weather barely changes. Summer days average 85°F, while winter days dip to around 78°F.
Nights are usually about 10°F cooler than the day. It’s rare for the city to hit 90°F. February is the coolest month, hanging around 72°F, and August is the warmest at about 78°F.
Trade winds blow through most of the year, giving the city a nice breeze and keeping humidity down. When they stop, though, you get kona weather—hot and sticky.
Sitting on Oahu’s leeward side, Honolulu doesn’t get much rain. The city stays drier than the windward parts of the island.
Hilo: Rainfall and Climate
Hilo feels totally different from Honolulu. It’s on the windward side of the Big Island, so it ranks as one of the rainiest cities in the country.
Trade winds shove moist air up the mountains, where it cools and dumps a ton of rain. Most of that rain falls between November and March.
Hilo doesn’t get too hot, thanks to the constant clouds and rain. Humidity stays high because of all the moisture.
Microclimates pop up all around Hilo. Some spots get over 200 inches of rain, while others nearby stay much drier.
Mountain and Volcano Areas
Mauna Kea, Mauna Loa, and Haleakala all make their own weather. For every 1,000 feet you climb, temps drop about 3.5°F. These mountaintops can be a full 30°F colder than the beaches.
Haleakala’s summit sits at 10,023 feet. If you’re heading up, you’ll want pants and layers. The thin air means stronger sun, too.
Volcanic fog or “vog” sometimes drifts over areas near active volcanoes. Kilauea’s sulfur dioxide mixes with moisture and sunlight, making hazy air that can bug your eyes or breathing.
Snow sometimes falls on Mauna Kea and Mauna Loa. During winter, these peaks can freeze.
Monthly Weather Impact on Activities and Travel
Hawaii’s weather shapes what you can do and when. April, May, September, and October usually hit the sweet spot for nice weather, smaller crowds, and better deals.
Best Months for Outdoor Activities
April and May are great for just about anything outside. Temps run 75-85°F, and rain is moderate. It’s prime hiking season on every island.
June through August are the driest months, so if you want beach time or water sports, that’s your window. Trade winds keep things comfortable, even when it’s hot.
Surfing depends on the month and the beach. Winter (November to March) brings big waves to north shores. In summer, south shores get gentle waves, perfect if you’re learning.
September and October are another good stretch for outdoor plans. Rain drops off after summer, and temps stay warm but not crazy hot.
Winter (December to February) can make mountain trips tougher. Sometimes there’s snow on Mauna Kea. But you can do coastal stuff year-round.
Whale watching is best from January through March, when humpback whales show up in Hawaii’s waters.
Weather Considerations for Travelers
If you’re heading to Hawaii, pack for the islands’ microclimates rather than just the season. You might need shorts at the beach but a jacket once you hit the mountains—all in a single day.
The rainy season runs from November through April, so you’ll probably see afternoon showers. Usually, rain falls in short bursts, maybe 30 to 60 minutes. If you’re planning outdoor activities, waterproof gear definitely helps.
Hurricane season stretches from June through November. Actual hurricanes almost never reach Hawaii—just four major strikes since 1957. Still, tropical storms roll through more often than you’d expect.
Peak tourist seasons can make the weather feel different because of the crowds. December through March and June through August are the busiest. If you can visit during the shoulder months, you’ll probably enjoy better weather and fewer people.
No matter when you go, grab some sunscreen. Hawaii sits close to the equator, so UV exposure gets intense, even if it’s cloudy. The sun just feels stronger here than on the mainland, even when the temperature seems mild.
Heavy rain sometimes causes flash flooding. If there’s a storm warning, avoid hiking in valleys or near streams.
Long-Term Trends and Weather Variability
Over the decades, Hawaii’s tropical climate has changed, with some islands seeing big shifts in rainfall and temperature. Each year brings its own weather quirks, making it tough for visitors to predict what they’ll get.
Year-to-Year Weather Variations
Hawaii’s weather swings a lot from year to year, even in the same season. Some years, the wet season from November to April brings way more rain than usual.
El Niño and La Niña have a huge impact on weather patterns. El Niño years tend to be drier, with less rain. La Niña usually means wetter weather and more tropical storms.
The amount of rain the islands get changes a lot each year. Sometimes a dry year has just half the normal rainfall. On the flip side, a wet year can bring double the usual precipitation.
Temperature changes from year to year aren’t as dramatic, but you’ll still notice them. Most years stay within two or three degrees of the long-term average. Ocean temperatures move up and down too, which affects swimming and marine life.
Hurricane activity jumps around a lot. Some years, Hawaii doesn’t see any storms. Other years, several tropical systems roll by and shake up the weather for weeks.
Changing Climate Patterns in Hawaii
Since 1950, Hawaii’s climate has changed a lot. Some places have gotten much drier, and the Big Island stands out for the most dramatic shifts in weather.
Rainfall has decreased across many parts of Hawaii over the past 70 years. Hilo, sitting on the Big Island, now gets 14 inches less rain each year than it did in 1950.
That’s a huge shift for what used to be one of the wettest cities in the United States.
The dry season has become longer on several islands. Places that used to have clear wet and dry seasons now go through even longer stretches without much rain.
Higher elevations tell a different story than the coast. Mountain regions on some islands are getting wetter, but the coastal zones keep drying out.
This mix creates new weather patterns and changes for local ecosystems. It’s not always easy to predict what comes next.
Ocean temperatures around Hawaii have crept up over the decades. Warmer waters shake up the usual weather patterns and can even influence how storms develop.
All these changes keep shifting Hawaii’s tropical climate. These days, visitors notice more ups and downs in the weather than folks did a few decades ago.