Osaka weather in September
September in Osaka: sweltering, soaked, with muggy air — a gamble, with 13 rainy days.
Updated September 2026 · climate normals from ERA5 reanalysis
#10 of 12 months in Osaka · #1119 of 1413 destinations to visit in September · comfort 61/100 (tier C)
- Days
- 30°C
- Nights
- 23°C
- Wet days
- 13
- Sun
- 8.4 h
- Humidity
- 78%
- Daylight
- 12 h

What September is like in Osaka
Still hot and still in typhoon season; the heat breaks only in the last week.
typhoonlow season
confidence: high
Traveller notes on Osaka in September
Other months in Osaka
Regulars are specific that the coldest winter stretch usually doesn't set in until late December, and even then it isn't brutal, especially during the day - mornings can start in the low single digits Celsius before climbing to a manageable afternoon. Our row backs that cool-not-harsh read, 12.9C over 5.5C nights feeling 3C, with 49.3mm of rain across 5.6 days and only a trace of snow, 0.2cm, matching regulars' consensus that real snow in the city itself is genuinely rare. Regulars are consistent that conditions stay dry and often sunny rather than gray, a real upside for a December city trip. A warm layer for the evenings is the standard packing tip, not a heavy winter coat. The sea sits at a cold 11.9C. The record: humidity 75 percent, 7.4 hours of sun, a 15.1 kph wind and AQI 56.
Late March here swings hard - one day mild, the next genuinely cold - and regulars pack for both: long sleeves, a sweater, a light jacket and something that rolls up small. Our row gives 15.7C reading as 14C and 7C nights that feel like 4C, with 104.6mm of rain across 9.9 days, so the umbrella is not optional either. On the blossom they are careful: the trees will be somewhere between budding and open depending on the year's warmth, and the forecast is the only guide. This is the same caution kagoshima/3 records further south, where the season starts earlier. The record: humidity 72 percent, 8.4 hours of sun and AQI 64.
Regulars rate October among the best months here - warm clear days, cool but not cold evenings, few tourists and no major holidays - and add two corrections. Typhoons rarely reach this far into the month; they usually finish earlier, and a late one is likely just a day of rain. And there is no autumn colour yet: the leaves in Osaka and Kyoto do not turn until mid-November, so anyone booking October for foliage has the wrong month. Our row queries their word dry, at 170.9mm across 11.5 days under 7.7 hours of sun, though the temperature matches at 24.3C over 16.6C. A light jacket and a sweater, not a coat. The record: humidity 77 percent, a 22.7C sea and AQI 55.
April in Osaka is the blossom month with a deadline attached. Regulars put the season from the end of March to about mid-April and are blunt that by the 15th to the 22nd you have missed it in the city; Mount Yoshino in Nara is the day trip they send late arrivals on. The temperatures they give - 10 to 20C - bracket our row's 11.9C nights and 21C days, and the packing follows from that: layers, long sleeves over a t-shirt, a jumper or light jacket for the evening, and no need for a proper coat. The item they insist on is a rain jacket, because April here is wet - our row carries 137.3mm across 9.8 days. The record: 8.9 hours of sun, humidity 72 percent and AQI 70.
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Osaka climate normals — September
Monthly averages from ERA5 reanalysis. AQI is the mean US Air Quality Index for the month.
Crowds in Osaka in September
How busy the place itself is — school and mass holidays, the months an editor tagged, and how sought-after the weather makes them. Never part of the comfort score.
Quietthe editor's quiet month, Kishiwada Danjiri Matsuri, school holidays in 3 of the markets that fill it
Peak crowdsBusyShoulder seasonQuiet
Best months for Osaka's weather
Ranked by this destination's own climate comfort score across the year — a different thing from how busy it gets (see Crowds above).
Toughest weatherOsaka's best weather comes in April, May and November — separate windows, not one continuous season.
September coincides with Typhoon season.
Best weatherFair weatherToughest weather
What's on in Osaka in September
Recurring seasonal events, natural spectacles, closures and holidays — curated and sourced.
- Hazard
Typhoon season
1 Aug – 30 Sep · usuallyClosuresKansai Airport sits on a man-made island in the bay and shuts when a serious system comes up the coast. Late summer is when that is most likely. Source ↗
- Festival
Kishiwada Danjiri Matsuri
18–20 SepReligious feastCrowdedTeams sprint wooden shrine floats around street corners at full speed half an hour down the coast. It is genuinely dangerous and completely unmissable. Source ↗
Nearby, and something's on
Within 300 km of Osaka — a day trip or a short hop — with something on this month. Never part of the comfort score.
Where is Osaka?
Osaka in September — FAQ
- Is September a good time to visit Osaka?
- September in Osaka: sweltering, soaked, with muggy air — a gamble, with 13 rainy days. It ranks #10 of 12 months for Osaka on SeasonMap's comfort score (61/100).
- What is the weather like in Osaka in September?
- In September, Osaka averages a daily high of 30.3°C and a low of 23.1°C, with about 170.7 mm of rain over roughly 13.3 rainy days.
- What is the air quality in Osaka in September?
- Osaka has a mean US Air Quality Index of about 65 in September.
Within 300 km: Matsumoto's Kamikochi open season around 17 Apr – 15 Nov, and Kanazawa's Kanazawa Jazz Street on 19–21 Sep.