The weather forecast for the Big Island indicates a series of partly cloudy and breezy conditions accompanied by varying chances of showers, with several areas expected to experience rain over the next few days.
As we head into tonight, Hilo is set to remain partly cloudy, with scattered showers expected. Temperatures will range from low 62 to 69 near the shore, dropping to 49 to 56 at 4000 feet. Northeast winds up to 10 mph will shift to the northwest around midnight, with a 50 percent chance of rain.
In Kona, conditions will be mostly cloudy with showers likely in the evening, transitioning to partly cloudy with isolated showers after midnight. Haze may also be present throughout the night. Overnight temperatures will hover around 71 near the shore, with cooler temperatures of 45 to 51 near 5000 feet. Winds from the northwest will calm down, becoming light by the evening, and a 70 percent chance of rain is expected.
Waimea will experience breezy conditions tonight, with partly cloudy skies and isolated showers. Temperatures will range from 61 to 70 near the shore, dropping to 52 to 61 near 3000 feet. East winds at 10 to 20 mph will be present, but the chances of rain are lower at 20 percent.
Kohala will see similar weather to Waimea tonight, with breezy conditions, isolated showers, and partly cloudy skies. The temperatures will match those of Waimea, with lows of 61 to 70 near the shore and 52 to 61 near 3000 feet, under east winds of 10 to 20 mph and a rain chance of 20 percent.
In the South Big Island region, the forecast suggests mostly clear and breezy conditions, with scattered showers likely in the evening and haze persisting overnight. Lows will be around 72 near the shore, dipping to about 50 near 5000 feet, with a 40 percent chance of rain.
Puna’s forecast resembles that of Hilo, with partly cloudy skies and scattered showers expected overnight. Similar temperature ranges of 62 to 69 near the shore will prevail, and the chance of rain stands at 50 percent.
Finally, Waikoloa will experience partly cloudy skies with scattered showers in the evening, complemented by haze persisting overnight. Temperatures will range from 69 to 75 near the shore and approximately 49 to 54 above 4000 feet, with east winds of 10 to 15 mph and a 50 percent chance of rain.
Looking ahead to Wednesday, Hilo will transition to partly sunny skies accompanied by scattered showers. Daytime temperatures are forecasted to reach between 78 and 83 near the shore, while 4000-foot elevations will see temperatures around 66. Winds will remain consistent from the northeast at up to 10 mph, with a continued rainfall chance of 50 percent.
In Kona, scattered showers will still be present with partly sunny skies expected. Highs will range from 83 to 88 near the shore while temperatures near 5000 feet hover around 66. West winds up to 10 mph will be observed, again featuring a 50 percent chance of rain.
Waimea will continue to experience breezy conditions with mostly sunny skies. Daytime highs are expected around 79 near the shore, reaching 69 to 78 near 3000 feet, all under east winds ranging from 10 to 20 mph and a rain chance of 20 percent.
Kohala’s forecast reflects that of Waimea, with breezy and mostly sunny conditions, scattered isolated showers, and similar temperature ranges.
The South Big Island’s weather on Wednesday predicts mostly sunny conditions in the morning, turning partly sunny later in the day, with scattered showers likely as haze persists. Highs are expected to be around 86 near the shore and about 65 near 5000 feet, with east winds of 10 to 15 mph and a 50 percent chance of rain.
Puna will see similar conditions on Wednesday as Hilo, with a forecast of partly sunny skies and scattered showers. Daytime temperatures will match those of Hilo.
Waikoloa’s weather on Wednesday features mostly sunny skies in the morning, switching to partly sunny with scattered morning showers and isolated showers in the afternoon. Highs will reach between 82 to 89 near the shore and from 63 to 70 above 4000 feet, with a 50 percent chance of rain.
Wednesday night’s forecast continues the trend of mostly cloudy skies with scattered showers overnight. Lows in Hilo will remain between 63 to 69 near the shore and 49 to 56 at 4000 feet, under northeast winds shifting to northwest after midnight, with a 50 percent chance of rain.
Kona will experience mostly cloudy conditions with scattered evening showers and then partly cloudy skies later in the night, presenting a continued haze. Low temperatures will be around 72 near the shore and around 46 to 51 near 5000 feet. The chance of rain returns at 50 percent.
Waimea and Kohala’s night forecast includes partly cloudy conditions with isolated evening showers. Lows will again range from 62 to 71 near the shore and 52 to 61 near 3000 feet, under breezy east winds and a rain chance of 20 percent.
The South Big Island will remain partly cloudy with isolated showers in the evening and haze throughout the night. Overnight lows are forecasted to stay constant around 72 near the shore and around 50 near 5000 feet, accompanied by breezy east winds and a 20 percent chance of rain.
Puna follows suit with mostly cloudy and scattered shower conditions, with lows remaining the same as earlier in the week.
Lastly, Waikoloa’s weather on Wednesday night sees partly cloudy skies and isolated showers in the evening, with lows expected between 70 to 75 near the shore and 49 to 54 above 4000 feet, again under east winds of 10 to 15 mph and a rain chance of 20 percent.
As forecast models suggest, moderate to locally breezy trade winds will deliver showers to windward and mauka areas throughout the week, while some showers will decay and reach leeward regions.
There are expectations for heavier showers and potential thunderstorms late Wednesday through the weekend due to a disturbance aloft moving over the island chain.
Current radar indicates conditions with partly cloudy skies and isolated showers primarily over windward slopes. With a persistent trade wind flow expected, winds will strengthen slightly through Thursday due to a weak upper-level low moving slowly off the northeastern coast of the Big Island.
Reports predict that as the low pressure system deepens over the northwestern region, temperatures aloft will cool, leading to thundershowers and heavier downpours beginning Wednesday evening and continuing to Saturday.
This low is anticipated to weaken and move northwest on Sunday, expected to bring a reduction in overall rainfall and yield drier weather, coinciding with the holiday weekend.
Aviation conditions are forecasted to include breezy trade winds with the potential for low-level turbulence, particularly over and downwind of terrain. There may be areas of MVFR conditions along windward slopes.
Besides afternoon clouds and sporadic showers along the Kona slopes, VFR will dominate over leeward areas. Increased chances for heavier showers and thunderstorms are anticipated as the upper-level low approaches on Thursday.
In the marine outlook, surface high pressure moving far north across the island will sustain moderate to locally strong trade winds until Friday. Small Craft Advisories are currently in effect for the treacherous waters surrounding the Big Island.
The high pressure system is forecasted to pull back westward during the weekend, while a series of frontal systems will migrate far to the north, likely reducing wind speeds across the islands.
Surf conditions along south-facing shores are predicted to remain just below seasonal averages through Thursday. A small, long-period south-southwest swell is anticipated to affect the area late Thursday, bringing surf levels in line with average conditions through the weekend.
Conversely, east shore surf will remain near seasonal averages, yet will likely see a gradual decline during the weekend and early next week, while north-facing shores are expected to see minimal surf throughout the week.
To conclude, the Big Island’s weather remains dynamic, with variable conditions and frequent chances for rain throughout the week. Residents and visitors should remain alert and prepared for sudden weather changes as a disturbance approaches the islands.
image source from：https://bigislandnow.com/2025/05/20/hawaii-county-weather-forecast-for-may-21-2025/
