Weather on the Big Island, Explained

One island runs from a beach at sea level to snow near 13,800 feet, and from 9 inches of rain a year to nearly 200, close to a twenty-fold spread in rainfall. Where you stay on the Big Island matters far more for your weather than when you visit.

Hilo, on the windward east, is one of the wettest cities in the country. Waikoloa, 60 miles west, is drier than parts of the Sonoran Desert. Between them stand Mauna Kea and Mauna Loa, both dusted with snow most winters. Pick your coast and your elevation first.

The best time to visit the Big Island

For weather alone there is no bad month: Kona and the Kohala resorts stay warm and dry year round, while Hilo and Volcano are green and showery in every one. The drier stretch island-wide runs from late spring into fall. Prices and crowds move more than the weather does, and our full guide to the best time to visit the Big Island breaks those down month by month.

Hurricane season runs June through November, though a direct hit is rare. Our Hawaiʻi weather overview covers the season, and how the islands compare, in full.

The island at a glance

The extremes worth knowing before you pick a base: the wettest and driest coasts, the warmest beaches, the coldest summits, and where the beach-day odds run highest. Each card jumps to the detail below.

Month by month: temperature, rainfall, and cloud

Winter is the wetter half almost everywhere, summer the drier, but that seasonal swing stays small next to the gap between the coasts. Temperature, rainfall, and cloud each shift a little through the year, and the three maps here track them across the island, month by month.

Daytime warmth barely changes at sea level

At the coast, temperatures vary by only a few degrees across the year. Kona averages 84°F highs and Hilo 81, and Hilo’s spread between its coolest and warmest month is only about 5°F (Saul Price, Atlas of Hawaiʻi climate chapter, 1983). Elevation, not season, is what cools the air: reckon roughly 3 to 4 degrees lost per thousand feet, so Volcano at 4,000 feet runs 12 to 16 degrees below the coast, and the summits sit near or below freezing.

Average daytime high for each month, draped over the island’s terrain. Every month uses the same color scale, so any two months can be compared directly. These are monthly averages of the daily high, so a warm afternoon is warmer than the figure shown. Data: Evapotranspiration of Hawaiʻi (Giambelluca et al. 2014), 250 m grid. Map by Love Big Island.

Rainfall depends on which slope you’re on

Averaged over the island the wet season peaks in winter, but the gap between slopes is far larger than the gap between seasons. The windward east and the 2,000-to-4,000-foot slopes get the heaviest rainfall, close to 200 inches a year in the wettest spots above Hilo. The leeward Kona and Kohala coasts stay in single or low double digits, under 10 inches at Waikoloa. The wettest slopes get more rain in a single month than the driest coast gets all year.

The map below shows the same rainfall month by month on one fixed scale: the windward east stays wet in every frame while the Kona coast stays almost dry.

Average rainfall for each month, draped over the island’s terrain. All twelve months share one color scale, so a wet month and a dry month can be compared directly. March averages 8.4 inches across the island, June 4.3. The wet and dry areas are the same every month, and only the totals change. Data: Rainfall Atlas of Hawaiʻi (Giambelluca et al. 2013), 250 m grid. Map by Love Big Island.

Cloud and sun

The clearest skies on the island sit in two very different places: the leeward Kona and Kohala coast, and the summits above the trade-wind inversion. The cloudiest band wraps the windward slopes at 2,000 to 4,000 feet. On the Kona side skies are clearest in the morning; sea breezes build cumulus up the slope by early afternoon.

Average cloud cover for each month, on the island’s terrain. All twelve months share one color scale, so a cloudy month and a clear month can be compared directly. March averages 57% across the island, September 41%. The clearest ground of all is the high summits and the saddle, which sit above the cloud layer at about 25%. Data: Evapotranspiration of Hawaiʻi (Giambelluca et al. 2014), 250 m grid. Map by Love Big Island.

How the trade winds shape local weather

The trades arrive from the east and northeast and climb the windward slopes, dropping their rain on the way up and sliding down the leeward side dry. On the Big Island a second mechanism adds to this: a trade-wind inversion, a stable layer usually between 5,000 and 7,000 feet, present most of the time. Below it the air is moist and cloudy; above it the air is dry and clear. So the very high slopes and the two summits are among the driest, clearest places on the island, and Mauna Kea stays cool and dry from about 7,000 feet up.

Trade winds arrive from the northeast almost year round, as a broad front rather than from any one point. They split around Mauna Kea and Mauna Loa instead of climbing them, so the windward side stays wet and Kona sits in the lee. Kona winds are the exception and come from the southwest. The arrows show the prevailing pattern rather than measured wind. Terrain from USGS 3DEP. Map by Love Big Island.

Read more about the 8 climate zones on the Big Island, which come from this split between wet and dry sides and high and low ground.

Weather by region

If you’re staying higher up, we have the same month-by-month detail for Volcano, up near 4,000 feet, and Waimea, in the uplands between Kohala and Mauna Kea.

Kona: the dry, sunny coast

Kona has the island’s beach weather, warm and dry and sunny, with roughly 10 inches of rain a year down at Keāhole and nearer 27 up in Kailua-Kona town. Skies are clearest in the morning, because afternoon sea breezes climb the slope and build cloud, and in summer the odd thunderstorm.

Kailua-Kona on the same 0 to 18 inch rainfall scale used for Hilo. The bars are thin: Kona averages about 27 inches a year. Data: Giambelluca et al. (2014), Climate of Hawaiʻi. Chart by Love Big Island.

Our Kailua-Kona weather page has the same month-by-month averages for the town.

Kohala and the Waikoloa resort coast

The leeward coast north of Kona, from Waikoloa up through Mauna Lani and the Mauna Kea and Hāpuna resorts, is the island’s driest ground. Waikoloa Beach Resort averages just 9.4 inches of rain a year, the driest weather station on the island. The lava-field coast here sits in a deeper rain shadow than Kona and builds less afternoon cloud, so beach-weather odds run high in almost every month. The coast here is black lava rather than green hillside.

Our Waikoloa weather page has the month-by-month averages for the resort coast and the hour-by-hour cloud pattern.

Hilo: the rainiest city in the United States

Hilo holds the title for how often it rains, not how hard. On the 1991 to 2020 airport normal the airport gauge records 273 days a year with measurable rain, about three in four, and totals 120 inches. A couple of Alaska towns get more total rain. Most of those days are light, and the showers clear within the hour, and the hills stay green year round. Hilo has no dry season: its driest month still averages over 7 inches.

Hilo, average weather by month. The rainfall bars use a 0 to 18 inch scale: Hilo averages 142 inches a year on the UH grid, between the 120-inch airport gauge and the 151 up the slope. Data: Giambelluca et al. (2014), Climate of Hawaiʻi. Chart by Love Big Island.

Our Hilo weather page has the same month-by-month averages for the town.

The summits: snow, cold, and thin air

Mauna Kea and Mauna Loa both rise near 13,800 feet, and both see snow most winters, generally above 11,000 feet and most likely between October and April. The NWS puts daytime highs in the 50s and 60s at the summits and overnight lows in the 30s and 40s, colder in a storm, and the mountain is dry as well as cold above the inversion.

If you drive up Mauna Kea, past the Visitor Information Station at 9,200 feet the road is steep gravel and closed to two-wheel-drive vehicles, and at 14,000 feet there is about 40 percent less oxygen than at sea level. Acclimatize at the Visitor Information Station before heading higher, and skip the summit if you are pregnant, bringing young children, or have a heart or lung condition.

Beach days and ocean conditions

You get the most beach days on the leeward Kona and Kohala coast, dry and bright most of the year, while the windward east gets trade showers in every month. High surf and brown water can both spoil a swim on an otherwise sunny day, and neither shows up in a weather forecast.

Beach days

The Big Island’s beach weather changes more from coast to coast than from day to day. Thirteen of them rate below.

A beach-weather rating for thirteen Big Island beaches, deep blue for the best. Each card marks the beach’s score out of 100, the month it’s at its best, how cloudy a typical day runs hour by hour, and the clearest hours in orange (or fairly even all day where cloud barely shifts).

The beaches on the Kohala and North Kona coast rate highest. Hāpuna, Kaunaʻoa, Kua Bay and their neighbors are dry and often clear, at their best in September. Kailua-Kona’s beaches rate a step lower because the slope clouds over through the afternoon, so go in the morning. The windward Hilo and Puna beaches are the wettest and cloudiest on the island, and the little clear sky they get comes in the early afternoon rather than the morning. Punaluʻu and the Kaʻū green-sand beach sit in between.

How we rate the beach days

We rate each beach on how many good beach hours you can count on. The score comes from how much rain falls and how cloudy the sky is, averaged month by month over thirty years. The scores are relative, comparing these beaches with each other rather than promising sun on any day: a higher one means more dry, bright days over the year. The best month is the month that scores highest, when rain and cloud are both at their lowest.

The clearest hours come from a separate record of how cloudy it gets hour by hour through a typical day, which gives the best time to be on the sand: mornings on the leeward coasts, early afternoon on the windward side.

The Big Island’s beaches come in black, green, and white sand, scattered across different coasts. Our guide to Big Island beaches maps which is where, and which are safe to swim.

Brown water

Brown water is what runs off the land after heavy rain: storm runoff carrying pathogens from cesspools and septic tanks, animal waste from storm drains, sewage from overflowing manholes, and chemicals from paved runoff. It turns the nearshore water murky and brown.

Stay out of brown water, and out of the streams feeding it, until it clears. The Hawaiʻi Department of Health sets no waiting period, so do not trust the common 48-hour figure; that number belongs to sewage and chemical spills, not storm water. Check the Clean Water Branch’s map of current beach advisories for what is posted where you are staying.

Surf

North- and west-facing shores see the big swells in winter; south-facing shores come up in summer. Large surf can still hit the north and west coasts in a dry, sunny February week, so check the National Weather Service Hawaiʻi surf zone forecast for the specific shore before you get in. Our guides to Big Island surfing and snorkeling cover the breaks and the calm coves by season.

Vog and air quality

Vog, the haze that forms when sulfur dioxide from Kīlauea reacts in the air downwind, is a hazard the other islands see far less of. When the volcano is emitting, the summit gives off on the order of 1,000 to 5,000 tonnes of SO₂ a day. The communities from Ocean View to Hilo get both the gas and the fine particles; far downwind, the Kona side mostly gets the particles. Sensitive groups, children and anyone with asthma or a heart or lung condition, feel it first.

Kīlauea’s activity comes in episodes, so check the current level before a Kaʻū or Volcano visit rather than trusting any fixed number.

A 24-hour vog forecast for the Big Island, from the University of Hawāiʻi model run on August 7, 2026. Ground-level sulfur dioxide, the gas behind vog, pools over Kaʻū and the South Kona coast near Ocean View overnight, then thins by mid-morning, while Kailua-Kona and the windward Hilo side stay clear. On the leeward south side the air is cleanest in the morning, and it changes day to day, so check the live map before you go. Source: University of Hawāiʻi VMAP.

Where to check current vog conditions

Vog shifts day to day with the eruption and the wind, so there is no fixed map of it. Before a Kaʻū, Volcano, or Kona visit, check the live sources:

• The Hawaiʻi Interagency Vog Dashboard: the vog forecast and current conditions, run jointly by the state Health Department, USGS, and the National Weather Service.
• The Hawaiʻi SO₂ Index: live sulfur-dioxide monitor readings on a green-through-maroon health scale.
• The USGS Hawaiian Volcano Observatory: current eruption status and gas-emission rate, updated daily.
• For the park itself, Hawaiʻi Volcanoes National Park’s weather and air-quality page: conditions and closures on the summit and Kaʻū side.

Sources and methods

• Station rainfall and temperature: NOAA 1991 to 2020 climate normals and the UH Rainfall Atlas of Hawaiʻi (1978 to 2007), each named where used. Extremes drawn only from well-observed stations.
• Island rainfall, temperature, and cloud maps: University of Hawaiʻi 250-meter grids (Giambelluca et al. 2013, 2014), draped over USGS 3DEP terrain.
• Beach-weather map: each beach rated on the UH 250-meter rainfall and cloud grids above, with the best time of day from the hour-by-hour cloud grid; base relief from the Terrarium DEM (SRTM/3DEP), roads © OpenStreetMap.
• Snow, summits, and the inversion: NWS Honolulu, UH Hilo Maunakea stewardship, and the 1983 Atlas of Hawaiʻi climate chapter (Saul Price).
• Vog and SO₂: USGS Hawaiian Volcano Observatory and the Hawaiʻi interagency vog dashboard (DOH / USGS / NWS).
• Explore the data yourself: the UH Hawaiʻi Climate Data Portal publishes interactive climate maps, live readings from the Hawaiʻi Mesonet station network (live data), and monthly climate summaries.

Maps and charts on this page are made by Love Big Island from the public datasets above. Averages are long-term normals: a given day can and will run above or below them.