ヒロ 5月の天気
ヒロの5月:暑い、大雨続き、空気がきれい — 雨の日22日が気にならなければ悪くない時期。
2026年9月更新 · ERA5再解析による気候平年値
ヒロでは12か月中3位 · 5月に訪れたい旅行先で1413か所中989位 · 快適スコア72/100(Bランク)
- 日中
- 28°C
- 夜
- 20°C
- 雨の日
- 22
- 日照
- 11.7 h
- 湿度
- 85%
- 日の長さ
- 13 h

5月のヒロについての旅行者の声
Hilo is the rainiest town in the United States, well over 200 inches a year, and locals still name May and June as the best time on this side of the island. Our row shows how both are true at once: 195mm across 22 precipitation days, and 11.7 hours of sun a day. The pattern they describe is squalls that blow in off the bay, dump hard and are gone, with a shower in the morning and another in the afternoon between stretches of sunshine - so the sky changes several times a day rather than settling. May is not the wettest month of the Hilo year. The island is two climates: rain on this side, dry over in Kohala, and a bad forecast here says nothing about there. The record: 28C over 20.1C reading as 31C, humidity 85 percent, a 24.9C sea and AQI 26.
ヒロのほかの月
Regulars are specific this counts as one of the wetter, more humid months of the year here, June through November generally the most humid stretch, with heavy but short-lived showers typically arriving at night rather than disrupting the day. Our row backs that hot, genuinely wet read, 29C reading as a scorching 33C, over 21.4C nights feeling 23C, with a substantial 180.7mm of rain across 22.4 days and humidity at 83 percent. Regulars are consistent daytime temperatures in the 80s Fahrenheit feel noticeably hotter than the number alone suggests given the humidity, this side of the Big Island reliably wetter than the leeward Kona coast. The sea sits at a warm, swimmable 26.1C. The record: 12.2 hours of sun, a 19.1 kph wind and AQI 20.
Regulars name March one of this side of the island's two wettest months, alongside November, and explain the mechanism: trade winds carry moisture off the Pacific, and the clouds squeeze out rain as they climb the cooler slopes of the two big mountains, arriving as a squall that can turn a sunny minute into a downpour and back again within the hour. Our row backs the intensity, 249.4mm across 19.4 days at 85 percent humidity, alongside 26.9C reading as a real 30C over 18.9C nights. Their practical answer to a full washout is a short list of indoor stops - the Pacific Tsunami Museum, the Lyman Museum, Imiloa Astronomy Center - though most days the rain is the shower-then-sunshine kind that barely interrupts a plan. The sea holds 24.3C. The record: 10.3 hours of sun, a 17.8 kph wind and one of the cleanest air readings in this project, AQI 27.
Regulars here make two points that sound contradictory and are not. February is among the drier months on this coast - November is the wet one - and this coast takes two to three hundred inches a year. Both hold because of how it falls: a squall blows in, it pours, and shortly after it is sunny again, repeating through the day. Our row is that pattern in figures, 306.7mm across 16.4 days, nineteen millimetres each. They also warn against planning on it: dry spells of a week happen on the windward side, but nobody can say which winter month will get them. Days are 26.6C over 18.1C at 84 percent humidity. The record: 10.1 hours of sun, a 24.5C sea and AQI 32.
Hilo is among the wettest cities in the United States and the forum's regulars neither deny it nor let it put you off: the usual pattern is a shower in the morning, another in the afternoon and sunshine in between, rather than a day under an umbrella - and the rain is what makes this side of the island green. January is not cold here either, only 5 to 10 degrees F below Kona. The caveat they add is about altitude: Volcanoes National Park sits near 4,000ft, is markedly cooler and damper, with highs around 66F, and is worth doing in a rain jacket whatever the sky. The record: 27.3C days, 18.3C nights, 12.8 precipitation days carrying 182.4mm, humidity 84 percent, a 25.2C sea and AQI 23.
地図のヒロのカードから自分のメモを追加できます。
ヒロの気候平年値 — 5月
ERA5再解析による月平均値です。AQIはその月の平均US AQI(米国大気質指数)です。
5月のヒロの混雑
その場所自体の混み具合 — 学校休暇や大型連休、編集部がタグ付けした月、そして天気の良さによる人気の高さ。快適スコアには含まれません。
混雑天気が一年で最も良い月のひとつ(推定)
ピークの混雑混雑ショルダーシーズン閑散
ヒロの天気が良い月
この旅行先自身の一年間の快適スコアでランキングしています — 混み具合とは別のものです(上の「混雑」を参照)。
天気はまずまずヒロの天気は一年を通じて大きく変わりません — どの月も快適さはほぼ一定です。
5月のヒロのイベント
毎年の季節のイベント、自然の見どころ、休業、祝日 — 厳選し出典を明記しています。
- 自然
Humpback whale season
11月15日〜5月15日Humpbacks come down from Alaska to breed in Hawaiian water between about November and May, peaking from January to March. Hilo Bay gets fewer than the leeward side, but they can be watched from the shore.
近くで開催中のイベント
ヒロから300 km以内 — 日帰りやちょっとした移動で行けて、今月何かがある場所です。快適スコアには含まれません。
ヒロはどこにある?
5月のヒロ — よくある質問
- 5月はヒロを訪れるのに良い時期ですか?
- ヒロの5月:暑い、大雨続き、空気がきれい — 雨の日22日が気にならなければ悪くない時期。SeasonMapの快適スコアでは、ヒロの12か月中3位です(72/100)。
- 5月のヒロはどんな天気ですか?
- 5月のヒロは、平均最高気温28°C、最低気温20.1°C、降水量は約195 mmで、雨の日はおよそ22日です。
- 5月のヒロの大気質はどうですか?
- 5月のヒロの米国大気質指数(US AQI)は、平均約26です。
300 km圏内:MauiのUpcountry jacaranda(5月1日〜6月15日ごろ)、LahainaのHumpback whale season(12月15日〜5月15日)。