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Weather in Kōyasan for September 2025

Your guide to Kōyasan weather in September - trends and predictions

    Temperatures

  • In general, the average temperature in Kōyasan at the beginning of September is 29.3 °C. As the month progressed, temperatures tended to significantly cool down, reaching an average of 26 °C by the end of September.

    • Rain 🌧️

  • Kōyasan in September brings notable rainfall, with an average of 18 rainy days and a total precipitation of 124 mm.

    • More

  • Is September a good time to visit Kōyasan? check out the best time to travel to Kōyasan page.

  • New! Chat with our AI weatherman - it’s amazing and free.

Average dry days
12
Dry days
Average rainy days
18
Rainy days
Average snowy days
0
Snow days
Average temperatures
29°/20°
Temperatures
Average wind speed
9 km/h
Avg max wind
Average humidity
80 %
Avg humidity

Kōyasan Weather September

Move between months or click on a day
August
October
Mon.Tue.Wed.Thu.Fri.Sat.Sun.
1
Patchy rain possible
25°
2
Overcast
31°
3
Heavy rain at times
29°
4
Overcast
29°
5
Patchy rain possible
30°
6
Cloudy
30°
7
Cloudy
31°
8
Cloudy
31°
9
Overcast
33°
10
Heavy rain at times
33°
11
Heavy rain at times
32°
12
Moderate or heavy rain shower
31°
13
Moderate rain at times
31°
14
Moderate or heavy rain shower
31°
15
Heavy rain at times
27°
16
Moderate or heavy rain shower
31°
17
Patchy rain possible
30°
18
Patchy rain possible
31°
19
Partly cloudy
32°
20
Sunny
32°
21
Overcast
29°
22
Moderate or heavy rain shower
26°
23
Overcast
24°
24
Patchy rain possible
25°
25
Sunny
27°
26
Overcast
28°
27
Patchy rain possible
28°
28
Heavy rain at times
25°
29
Moderate rain at times
24°
30
Moderate or heavy rain shower
25°

Temperatures trend during September in Kōyasan

See the weather trend as well as the moving average line

September weather in Kōyasan day by day

Click on a date for more information
August October
Date Weather Temperatures Rain UV More
1 Sept. Patchy rain possible
Patchy rain possible
 25° /21° 2.2 mm 5
2 Sept. Overcast
Overcast
 31° /22° 0.6 mm 7
3 Sept. Heavy rain at times
Heavy rain at times
 29° /21° 1.4 mm 6
4 Sept. Overcast
Overcast
 29° /20° 0 mm 6
5 Sept. Patchy rain possible
Patchy rain possible
 30° /19° 0.2 mm 7
6 Sept. Cloudy
Cloudy
 30° /19° 0 mm 7
7 Sept. Cloudy
Cloudy
 31° /19° 0 mm 7
8 Sept. Cloudy
Cloudy
 31° /20° 0.2 mm 7
9 Sept. Overcast
Overcast
 33° /22° 0.1 mm 7
10 Sept. Heavy rain at times
Heavy rain at times
 33° /22° 4.2 mm 7
11 Sept. Heavy rain at times
Heavy rain at times
 32° /21° 2.6 mm 7
12 Sept. Moderate or heavy rain shower
Moderate or heavy rain shower
 31° /22° 11 mm 7
13 Sept. Moderate rain at times
Moderate rain at times
 31° /21° 2.8 mm 7
14 Sept. Moderate or heavy rain shower
Moderate or heavy rain shower
 31° /21° 5.1 mm 7
15 Sept. Heavy rain at times
Heavy rain at times
 27° /22° 1.8 mm 6
16 Sept. Moderate or heavy rain shower
Moderate or heavy rain shower
 31° /21° 15 mm 7
17 Sept. Patchy rain possible
Patchy rain possible
 30° /21° 1 mm 7
18 Sept. Patchy rain possible
Patchy rain possible
 31° /21° 0.3 mm 7
19 Sept. Partly cloudy
Partly cloudy
 32° /22° 0 mm 8
20 Sept. Sunny
Sunny
 32° /22° 0 mm 8
21 Sept. Overcast
Overcast
 29° /23° 0.1 mm 6
22 Sept. Moderate or heavy rain shower
Moderate or heavy rain shower
 26° /18° 41.1 mm 6
23 Sept. Overcast
Overcast
 24° /17° 0 mm 5
24 Sept. Patchy rain possible
Patchy rain possible
 25° /17° 1.2 mm 6
25 Sept. Sunny
Sunny
 27° /16° 0 mm 7
26 Sept. Overcast
Overcast
 28° /19° 0 mm 6
27 Sept. Patchy rain possible
Patchy rain possible
 28° /20° 0.5 mm 6
28 Sept. Heavy rain at times
Heavy rain at times
 25° /20° 1.4 mm 6
29 Sept. Moderate rain at times
Moderate rain at times
 24° /19° 3.9 mm 5
30 Sept. Moderate or heavy rain shower
Moderate or heavy rain shower
 25° /16° 24.9 mm 6
Next
Important Notice
Our weather forecast for Kōyasan in September is based on the analysis of historical data rather than real-time forecast models. While this provides a general overview, weather conditions can change. We recommend that you check the Kōyasan forecast closer to your planned date for the most up-to-date weather information.
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Kōyasan in September - FAQ

What are the expected maximum and minimum temperatures in Kōyasan during September?
During September, expect a variety of temperatures with highs around 29° and lows near 20°, suitable for diverse activities and preferences.
How much rainfall should be expected in Kōyasan during September?
Significant rainfall exceeding 124 mm is expected in Kōyasan during September, occurring over more than 18 days. Preparing for wet conditions is recommended in your planning.
What are the typical wind conditions in Kōyasan during September?
The average wind speed in Kōyasan during September is 9 km/h, suggesting breezy to windy conditions, depending on your activities.

What to pack to Kōyasan in September?

As you prepare for your trip to Kōyasan in September, it's important to consider the typical weather patterns for the time of year. Below is a carefully tailored packing list to ensure that your time in Kōyasan, during September, is comfortable and enjoyable, regardless of the weather conditions.

  • Clothing
    • Lightweight Clothing: T-shirts, blouses, shorts, skirts
    • Rain Gear: Lightweight, waterproof clothing
  • Footwear
    • Waterproof Shoes
    • Sandals/Flip-flops: Comfortable for warm climates
  • Accessories
    • Sunglasses: For sun protection
    • Sun Hats: Wide-brimmed hats for sun protection in warm weather
    • Umbrellas/Raincoats: For rainy days
  • Personal Items
    • Sunscreen: High SPF for sunny destinations
    • Lip Balm with SPF: To protect against chapped lips

September rainfall patterns in Kōyasan

Explore the daily rainfall trends and prepare for Kōyasans September weather 💧

UV exposure in Kōyasan during September

Stay informed about UV levels for safe outdoor activities throughout the month of September ☀️

Quick links

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Location coordinates Where is Kōyasan?

Get accurate weather forecasts for Kōyasan, located at latitude 34.217 and longitude 135.583. Stay updated with localized weather information tailored for Kōyasan.

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