HILO – This Monday, July 21, clouds and showers continue to shape the weather across Hawaii County, with notable variations between the windward and leeward areas of the Big Island.
Tonight, skies over Hilo will remain mostly overcast, with scattered showers developing into numerous downpours after midnight. Temperatures will dip to 65–72°F (18–22°C) near the coast, dropping to 52–59°F (11–15°C) around 4000 feet. Northeast breezes will shift northwest late into the night. The chance of rain stands at 70%.
Monday brings partly sunny conditions in Hilo, though intermittent rainfall will linger, especially in windward zones. Temperatures are expected to peak at 80–86°F (27–30°C) near the shore and around 69°F (21°C) at higher elevations. Trade winds will reach up to 15 mph, with a 50% probability of rain through the day.
KONA, on the leeward side, will experience cloudy skies and scattered rain during the evening, becoming partly clear overnight. Lows will sit around 74°F (23°C) along the shoreline, dipping to about 54°F (12°C) near 5000 feet. Calm winds dominate, and rain chances remain at 40%.
The start of the week in Kona looks sunny with only isolated showers in the morning and a few more in the afternoon. Expect highs near 86°F (30°C) at sea level and 67–72°F (19–22°C) at higher terrain. Winds stay light, and the chance of precipitation drops to 30%.
In Waimea, breezy winds will persist overnight with cloudy skies and scattered rain. Temperatures will fall between 65–72°F (18–22°C) along the shore and 56–64°F (13–18°C) near 3000 feet, with east winds peaking at 20 mph. Rainfall probability remains 50%.
Monday in Waimea will be partly sunny and windy, with a high of 65–86°F (18–30°C) and continued scattered showers. Winds hold steady from the east at up to 20 mph, and the chance of rain hovers at 40%.
Kohala mirrors Waimea’s forecast, with breezy evening winds, clouds, and intermittent showers. Overnight lows range from 65–72°F (18–22°C) down to 56–64°F (13–18°C) inland. Monday will be partly sunny, breezy, and humid, with a 40% likelihood of rainfall.
In the South Big Island, skies stay mostly clear tonight, though breezy conditions will linger. A few isolated showers may occur. Expect lows near 75°F (24°C) along the coast, cooling to 56°F (13°C) around 5000 feet. Northeast winds will hit 20 mph, and the rain chance is just 20%.
On Monday, sunshine dominates the South Big Island, especially along the coastline, with brief afternoon showers possible. Highs could reach 87°F (31°C) near the ocean and 69°F (21°C) at elevation. Winds will peak at 25 mph from the east.
Puna will also see mostly cloudy skies and frequent showers tonight, especially after midnight. Temperatures will settle between 65–72°F (18–22°C) at the shore and 52–59°F (11–15°C) inland. Winds will shift northwest late into the night. Rain chances are elevated at 70%.
The daytime weather in Puna mirrors Hilo, with partly sunny skies and scattered rainfall, highs between 80–86°F (27–30°C) on the coast, and around 69°F (21°C) at higher spots. Winds from the northeast will max out at 15 mph, with a 50% chance of showers.
Waikoloa will be partly clear tonight with isolated evening rain. Lows will hover near 76°F (24°C) on the coast, falling to 56°F (13°C) above 4000 feet. Monday stays sunny with some afternoon sprinkles, highs between 85–90°F (29–32°C) on the shoreline, and 67–75°F (19–24°C) further uphill. Northeast breezes will reach up to 15 mph. Rain chances stay low at 20% throughout.
A drier air mass is slowly spreading across the Hawaiian Islands, triggered by high pressure over the Central Pacific. The windward zones, particularly in Kauai and the Big Island, experienced intense rainfall over the weekend, including localized flooding near the Hanalei Bridge.
Now, as precipitable water levels drop and stable conditions settle in, trade winds will remain moderate to breezy through the midweek, slowly tapering toward the weekend. Despite some moisture lingering along the windward slopes, most of the leeward regions are expected to stay mostly dry, raising fire weather concerns due to low humidity and dry vegetation.
Coastal flooding could become a minor issue between Monday and Wednesday during peak high tides, especially along low-lying shores. Meanwhile, small swells from the southwest will continue, with a slight bump in surf expected by Wednesday night.
