シアトル 5月の天気
シアトルの5月:快適、ときどき雨、空気がきれい — 訪れるのに絶好の時期。
2026年9月更新 · ERA5再解析による気候平年値
シアトルでは12か月中5位 · 5月に訪れたい旅行先で1413か所中477位 · 快適スコア85/100(Aランク)
- 日中
- 19°C
- 夜
- 10°C
- 雨の日
- 5
- 日照
- 10.8 h
- 湿度
- 74%
- 日の長さ
- 15 h

5月のシアトルについての旅行者の声
Regulars describe this as the most variable month of the year here, unlike the more settled fall and winter, with two genuinely distinct outcomes possible on any given day - sunny and into the low 70s Fahrenheit, or overcast with highs stuck in the upper 50s to low 60s. Our row backs the mild, changeable average across that range, 19.1C over 9.5C nights, with 34mm of rain across 5.3 days. Regulars are consistent this is still a genuinely good time to visit, flowers in full bloom and springlike energy throughout the city, with layering the standard advice given how unpredictable a specific day can turn out. The record: humidity 74 percent, 10.8 hours of sun, a 12.6 kph wind and AQI 44.
シアトルのほかの月
Regulars call this one of the city's best-looking months on paper, and are specific about why: the rains that define this region typically hold off until mid-October, and the first week of the month is often the driest and warmest stretch, with the back half cooling off a little as it goes. Our row backs the shift, 21.4C over 12.3C nights, with 35.5mm of rain across 5.6 days - a real total, but light next to what regulars describe arriving a month later. Evenings call for a light jacket or sweatshirt once the sun goes down. The one caveat some years bring is wildfire smoke drifting in from regional fires, not present every September but enough that regulars mention checking air quality before a trip built around outdoor views. The record: 9.5 hours of sun, a 12.3 kph wind and AQI 40.
Juneuary is the local word for the version of this month that feels like January, and the local claim is that summer does not start until the 5th of July - the same joke the Portland board tells, two hundred kilometres south. The instruction that follows is precise: the 30th of June is a different month from the 1st, so come at the end. Our row is kinder than the nickname. Rain is 29.5mm across 5.1 days, and there are 11.6 hours of sun inside 15.9 of daylight, so the grey is brief showers between sun breaks rather than a ceiling. What June lacks is warmth - 21.6C by day, 12C at night. The record: humidity 71 percent, a 12.5 kph wind and AQI 39.
Seattle-forum threads on August are almost giddy about the weather - this and the two months around it are the reliably dry, sunny stretch of the year, with posters calling a soggy day genuinely rare and temperatures running warm without the humidity that makes other cities miserable in summer. The one recurring caveat has nothing to do with rainfall: more than one thread flags wildfire smoke as the real risk, a haze that can roll in and ruin an otherwise perfect week with no warning. Cruise-ship crowds pack Pike Place Market and the Space Needle on port days. The record backs the dry read completely: 25.2C days, 14.7C nights, just 12mm total across 1.6 days, 11.4 hours of sun and an AQI of 44 - though that AQI can spike hard on a bad smoke day, which the average doesn't show.
Seattle forum threads describe February as genuinely mixed - some stretches bring drizzly, overcast, grey days typical of the region's wet season (which runs roughly mid-October through April), while other years bring a welcome week or so of milder, lighter-sun weather that winter-weary locals specifically look forward to. Snow chances were described as relatively low by this point in winter, with January and early February the more likely window for any accumulation. One consistent tip from posters familiar with the wider region: the northern Olympic Peninsula tends to run drier and sunnier than Seattle proper in February, a worthwhile alternative for anyone chasing better odds of sun.
通年のメモはシアトルの概要ページにあります。 地図のシアトルのカードから自分のメモを追加できます。
シアトルの気候平年値 — 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月のシアトルの混雑
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Seattle International Film Festival(推定)
ピークの混雑混雑ショルダーシーズン閑散
シアトルの天気が良い月
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)。
天気はまずまずシアトルの天気がピークを迎えるのは6月〜8月で、特に良いのは7月ごろです。
天気が最高天気はまずまず天気が厳しい
5月のシアトルのイベント
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。
- 祭り
Seattle International Film Festival
5月8日〜26日 · 例年混雑早めの予約をEleven days of screenings across a dozen city venues in the middle of May, and the one stretch of the year Seattle's cinemas queue down the block. Weekend tickets for the bigger titles go before the festival opens. 出典 ↗
- 祭り
Northwest Folklife
5月22日〜31日 · 例年音楽祭Four free days at Seattle Center over Memorial Day weekend, several hundred acts and no headliners. It is the unofficial start of the dry half of the year. 出典 ↗
- 季節
Junuary
5月25日〜7月4日 · 例年霧のシーズンリスクThe local name for the grey, cool weeks that sit on the city between late May and the Fourth of July, when the marine layer refuses to lift and everyone insists summer starts later here.
近くで開催中のイベント
シアトルから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。
シアトルはどこにある?
5月のシアトル — よくある質問
- 5月はシアトルを訪れるのに良い時期ですか?
- シアトルの5月:快適、ときどき雨、空気がきれい — 訪れるのに絶好の時期。SeasonMapの快適スコアでは、シアトルの12か月中5位です(85/100)。
- 5月のシアトルはどんな天気ですか?
- 5月のシアトルは、平均最高気温19.1°C、最低気温9.5°C、降水量は約34 mmで、雨の日はおよそ5.3日です。
- 5月のシアトルの大気質はどうですか?
- 5月のシアトルの米国大気質指数(US AQI)は、平均約44です。
300 km圏内:Victoria, BCのWhale watching season(5月1日〜10月15日ごろ)、PortlandのPortland Rose Festival(5月22日〜6月14日ごろ)。