Sendai Weather in September

 Season: Autumn
 Key points:
1.    Sendai has an overall hot weather in September, but it starts to turn cool in the late month.
2.    Although with the highest precipitation throughout the year, Sendai is scarcely rinsed by heavy rainfall but moistened by light rain from time to time.
3.    Some places in Sendai Jozenji Avenue will be very crowded during the Jazz Festival on the second weekend of September. 

Temperature: Hot Daytime Mostly, Cool Night

The hot climate lingers mostly in the daytime of early and mid-September, normally about 26-30 degrees Celsius (78.8-86 degrees Fahrenheit). However, there are possible circumstances that the highest temperature may exceed 34℃ (93.2℉) when it’s sunny. For example, it’s said that there were over ten days with the highest temperatures up to about 34-35℃ (93.2-95℉) in September 2025. Therefore, if you are planning your 2026 Sendai trip in the same month, you’d better prepare some summer clothes and keep hydrated, just in case. Delightfully, late September will see a cooling down trend, with the maximum temperatures of basically no more than 28℃ (82.4℉); and the night is accordingly much cooler than that of the previous period, at 14-20℃ (57.2-68℉), so you may need to add a thin coat outside your cool shirt.

Precipitation: Highest of the Year but Not Too Frequent

Sendai receives its highest average rainfall of the year in September, but don’t be alarmed by this figure, as the total rainfall for the month is about 188 mm, far less than in Tokyo. Furthermore, there aren’t too many rainy days, only about 13. This means there will be 2-3 days of heavy rain, with the rest of the time mostly light rain. Therefore, we would like you to check the weather forecast beforehand and avoid traveling in heavy rainy days, and prepare your rain gear for other times.

The average humidity is as high as 78%, so you probably still feel sticky in sunny weather in the first half of the month.

Daylight Duration & Sunshine Hours

Sunrise time (1st-30th): 05:07 – 05:32
Sunset time (1st-30th): 18:09 – 17:23
Average daylight duration (1st-30th): from about 13 hours to 12 hours
Average sunny days: 14 days
Average sunshine hours: 7 hours

The daylength is shortening over the month, yet the utilization rate of daylight hours is generally satisfactory as the frequency of sunny days increases and there are rare impacts brought by intense rain. You can spend more time for outdoor sightseeing and recreation. However, the UV index should not be ignored; it averages around 5, perhaps even higher on clear days, so sun protection measures should be properly implemented.

Packing Guide for Sendai Trip in September

 Clothing
Summer clothes like T-shirts, thin loose pants or shorts, and dresses are still appropriate during the daytime throughout September. One thing to note is that if you plan to stay in Sendai for several days in the early or middle period, it’s best to bring enough light, quick-drying clothes to facilitate timely change and washing after sweating. The early mornings and evenings in late September are quite cool, so it’s recommended to add a light jacket over your summer clothes and wear thin long pants.

 Shoes
You can choose to wear sandals or canvas shoes depending on your preference; the former is much cooler, while the latter is more comfortable for walking.

 Others

Sunhat and sunscreen are significant to bring considering the moderate UV rays. For extra sun protection, you can wear sunglasses and sun protective suit. Besides, it’s necessary to pack an umbrella in your bag in case it rains.

Seasonal Event You May Be Interested

Every year on the second weekend of September, a Jazz Festival is held on the streets of Sendai Jozenji. During this festival, about 700 bands from Sendai and other parts of Japan and abroad gather here to participate in the event, filling the streets and alleys with a joyful atmosphere of art. Of course, there are many other types of music played here, including Rock, Ska, Latin, and Gospel music. If you are into them, why not come for a visit!

Note: 
1.    The performance schedule will be published on the relevant Sendai website. If you want to secure a good spot, remember to arrive early for the designated time.
2.    Both indoor and outdoor performances are available. If you choose to performance outdoors, be sure to take precautions against sunburn.

Travel Suggestions & Information You Might Need

 The Jazz Festival attracts a large number of tourists over the two days, but only a few large stage areas, such as Sendai Kotodai Park, will be more crowded due to performances by well-known musicians; other performance areas will be less crowded. If you want a peaceful visit, consider attractions like the Zuihoden, Aoba Castle, or Osaki Hachiman Shrine, other than those around the business streets.

 As the summer travel peak in July and August comes to an end, the ticket prices for flights and trains in September will be more favorable.

Sendai Weather by Month