ロンドン 9月の天気
ロンドンの9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
ロンドンでは12か月中5位 · 9月に訪れたい旅行先で1413か所中535位 · 快適スコア84/100(Aランク)
- 日中
- 21°C
- 夜
- 12°C
- 雨の日
- 11
- 日照
- 7.8 h
- 湿度
- 78%
- 日の長さ
- 13 h

ロンドンの9月のようす
The best month here: warm days, no school holidays, parks still green and the late afternoon light going amber.
shoulder
確度:high
9月のロンドンについての旅行者の声
Regulars are candid that recent early-September stretches have run warm and sunny, but are careful to add that's no guarantee for any given year - the month can just as easily turn wet, windy and chilly. Our row backs the moderate average sitting between those extremes, 20.7C over 12.3C nights, with 56.2mm of rain across 10.6 days. Regulars picked this month specifically expecting lighter crowds than July or August alongside reasonably decent weather, and are consistent that layering plus an umbrella and cardigan for cooler evenings is the standard advice regardless of how the daytime weather turns out. The record: humidity 78 percent, 7.8 hours of sun, a 19 kph wind and AQI 46.
ロンドンのほかの月
Asked what to pack for late May, regulars give the only honest English answer: wet, dry, chilly, warm and sunny are all possible, so the list is layers, a light waterproof and shoes that will take five or six miles a day on uneven ground. Our row lands mild rather than warm - 18.9C reading as 17C in an 18.3 kph wind, over 9.8C nights - with 53.4mm of rain across 10 days, which is a shower every third day rather than a wet month. What May really offers is length: 15.6 hours of daylight with 10.5 of sun. The gardens are the reason people come now, and the last week of the month is also the dearest. The record: humidity 74 percent, a dew point of 7.8C and AQI 46.
London-forum threads on August are candid that it's the year's peak for crowds - school holidays fill the museums and attractions with families - though several posters note the weather itself runs milder than June or July, without June's harder sun. The catch more than one mentions: much of the city, from shops to older hotels, still doesn't have air conditioning, so a warm spell is felt more than the numbers alone suggest. August's record: 23.7C days, 14.8C nights, 53mm of rain across nine and a half days, 9.7 hours of sun and a clean AQI of 41 - comfortable weather, uncomfortable queues.
London regulars are unanimous that January is “cold and, at times, wet” rather than dramatic — expect “0°C and 10°C,” “damp, grey weather rather than freezing cold,” and snow that “never falls properly... when it does, it's over within hours.” The advice is layering over a full parka: warm coat, hat, scarf, gloves, with snow boots only needed if a forecast actually predicts sub-zero days. The upside forum posters keep repeating: attractions stay open, queues vanish, and hotel prices drop. Our record matches the “cold, not brutal” read: 7.4°C days, 1.7°C nights, 10.6 rain days and just 1.7cm of snow for the month.
Ask what June is like and Londoners on the forum answer with a range, not a number: "the June temperature in London could be anything from 20°C to 40°C," and "the weather in the UK has become even more unpredictable than usual." A more grounded regular puts typical daytime highs in the 70s Fahrenheit — maybe high 60s, maybe 80s on a hot day. The useful consensus is that June is one of the drier months and "an umbrella or a full waterproof jacket is unlikely to be needed," though it can equally be very dry or thundery. Standing advice is layers plus a light raincoat, which covers both. The unarguable part is daylight: this is the longest-light month of the year, and evenings run late. Our record has 20.7°C highs and 16.5 hours of daylight.
通年のメモはロンドンの概要ページにあります。 地図のロンドンのカードから自分のメモを追加できます。
ロンドンの気候平年値 — 9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。
9月のロンドンの混雑
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。
混雑繁忙期の合間、Open House Festival、London Fashion Week (Sep)
ピークの混雑混雑ショルダーシーズン閑散
ロンドンの天気が良い月
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)。
天気はまずまずロンドン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
9月のロンドンのイベント
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
Open House Festival
9月12日〜20日芸術祭混雑早めの予約をOver 600 buildings across all 33 boroughs, from private members' clubs to government offices, open free for two weekends; the popular sites need tickets booked well ahead. 出典 ↗
- 祭り
London Fashion Week (Sep)
9月17日〜21日大きな祭り混雑早めの予約をThe spring/summer counterpart to February's shows, with the same runway-week crush on hotels and central venues, timed a few days after the Open House weekend. 出典 ↗
近くで開催中のイベント
ロンドンから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。
ロンドンはどこにある?
9月のロンドン — よくある質問
- 9月はロンドンを訪れるのに良い時期ですか?
- ロンドンの9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、ロンドンの12か月中5位です(84/100)。
- 9月のロンドンはどんな天気ですか?
- 9月のロンドンは、平均最高気温20.7°C、最低気温12.3°C、降水量は約56.2 mmで、雨の日はおよそ10.6日です。
- 9月のロンドンの大気質はどうですか?
- 9月のロンドンの米国大気質指数(US AQI)は、平均約46です。
300 km圏内:BournemouthのNew Forest heather(8月1日〜9月10日ごろ)、BathのJane Austen Festival(9月11日〜20日)。