オースティン 9月の天気
オースティンの9月:猛暑、ときどき雨、空気がきれい — 午後37°Cの暑さ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
オースティンでは12か月中9位 · 9月に訪れたい旅行先で1413か所中1019位 · 快適スコア66/100(Cランク)
- 日中
- 34°C
- 夜
- 22°C
- 雨の日
- 4
- 日照
- 10 h
- 湿度
- 65%
- 日の長さ
- 12 h

9月のオースティンについての旅行者の声
Austin forum regulars split September cleanly in two: the early half is “horribly hot and humid” — some years running “highs between 95° and 107°F every day except for 3 days” in mid-month — while it “usually starts to cool off by the middle of the month” and the end of September reads as genuinely nice. Some locals go further and say to absolutely avoid September outright, calling it “just more summer here,” though the consensus among regulars is softer: fine to visit if you accept the early weeks will be hot. The practical workaround: mornings for outdoor activities, afternoons for swimming, shaded patios or indoor attractions. Late October into November gets named as the genuinely reliable alternative. Our record: 33.4°C days, 23.2°C nights and 7.4 rain days — hot and dry, backing the “still summer at the start” read over the “cooled off” framing for the month as a whole.
オースティンのほかの月
Regulars call this the most unpredictable month of the year here, capable of sub-freezing cold or 60-plus Fahrenheit warmth within the same week - one recent February never dropped below freezing at all and ran genuinely hot, while a different year brought a full week of snow and ice. Our row backs the moderate average sitting between those real extremes, 19.6C over 7.4C nights feeling 5C, with 52.2mm of rain across 4.9 days and a trace of possible snow, 0.9cm. Regulars are direct that the practical response is flexibility rather than optimism - avoid non-refundable bookings and be ready to adjust plans on short notice given how fast conditions can flip. The record: humidity 70 percent, 6.8 hours of sun, a 20.5 kph wind and AQI 36.
October is the month regulars rate highest for weather here - late October into November is the best of the year - and the month the city is hardest to book. The festival weekends, the grand prix and the university's home games between them fill the hotels, push rates up and bring minimum stays, so the advice is to book early or choose the weeks between. If you are not going to the festival it barely touches downtown, because the music is all out at the park. Our row gives 29.4C over 16.5C at 62 percent humidity with 91.4mm of rain across 5.7 days - sixteen millimetres at a time. The record: 9.1 hours of sun, a 17.2 kph wind and AQI 38.
April is the month regulars hand out here, and the reason is the hill country: the bluebonnets run from March and the real show is usually early to mid April, with nothing left by summer. The weather half is a slope - pleasant and not yet hot at the start, hot and humid by the end, with nights still in the low teens. Our row averages 27.3C over 15.1C, a twelve-degree gap, at 68 percent humidity with a 21.4 kph wind. Rain is 108mm across 6.5 days, which means storms rather than showers when they arrive. Wildflower roads west of the city are the day out this month is for. The record: a dew point of 13.5C, 8.8 hours of sun and AQI 40.
November is the month Austin regulars hand over as the city's best weather, with the summer humidity gone and highs in the 60s and 70s Fahrenheit through the first half. The month does not hold still, though: by late November it has turned, shorts are unlikely, and the standing description of the swing is 40 one day and 75 the next. What they suggest packing for the last week is jeans, a long-sleeved shirt and a light jacket. Two practical consequences follow: the rivers are too cool for tubing by now, a heated pool aside, and the Hill Country is the day trip people name instead. Our row's 22.9C average high against 10.8C nights is that gap in one line. The record: 5.1 precipitation days carrying 56.2mm, 7.2 hours of sun and AQI 34.
地図のオースティンのカードから自分のメモを追加できます。
オースティンの気候平年値 — 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月のオースティンの混雑
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。
ピークの混雑Austin City Limits Festival、アメリカ合衆国のSummer break(推定)
ピークの混雑混雑ショルダーシーズン閑散
オースティンの天気が良い月
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)。
天気はまずまずオースティンの天気が最も良いのは3月、4月、11月です — ひと続きのシーズンではなく、別々の時期です。
天気が最高天気はまずまず天気が厳しい
9月のオースティンのイベント
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。
- 自然
Congress Avenue bats
3月20日〜11月1日 · 例年野生動物シーズンA million and a half Mexican free-tailed bats roost under the bridge from spring until they head south in the autumn. August, when the pups are flying, gives the biggest emergence at dusk. 出典 ↗
- 要注意
Blue-green algae on the lake
5月15日〜10月31日 · 例年藻類・赤潮休業The city posts warnings for toxic cyanobacteria on Lady Bird Lake through the warm months. It is a dog problem more than a swimmer's problem, but it closes the water access points. 出典 ↗
- 要注意
Texas summer heat
6月1日〜9月20日 · 例年酷暑Weeks of triple-digit afternoons with the run of hundred-degree days now routinely stretching into September. Anything outdoors happens before nine or after eight, or in Barton Springs. 出典 ↗
- 祭り
Austin City Limits Festival
9月30日〜10月13日 · 例年音楽祭混雑早めの予約をTwo consecutive three-day weekends in Zilker Park in early October, with the same lineup twice. The second weekend is usually the easier ticket and the cooler weather. 出典 ↗
近くで開催中のイベント
オースティンから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。
オースティンはどこにある?
9月のオースティン — よくある質問
- 9月はオースティンを訪れるのに良い時期ですか?
- オースティンの9月:猛暑、ときどき雨、空気がきれい — 午後37°Cの暑さが気にならなければ悪くない時期。SeasonMapの快適スコアでは、オースティンの12か月中9位です(66/100)。
- 9月のオースティンはどんな天気ですか?
- 9月のオースティンは、平均最高気温34.4°C、最低気温22.2°C、降水量は約62.8 mmで、雨の日はおよそ4日です。
- 9月のオースティンの大気質はどうですか?
- 9月のオースティンの米国大気質指数(US AQI)は、平均約44です。
300 km圏内:DallasのState Fair of Texas(9月25日〜10月18日)。