WEATHER
Yakushima is often blessed with clear skies and periods without rain. In the winter it`s a lot warmer than Honshu further north and in the summer it is cooler than the crippling heat of Kyoto. This being clarified, it is important to note that Yakushima receives the highest volume of rain in Japan! The annual rainfall is about 3,000mm around the coastal region and 10,000mm in the mountains. (Just to put that into perspective – the notoriously damp UK gets a maximum 2000mm – 3,000mm a year). The southern area of the island receives a considerably lower annual level of rainfall and this is most obvious in the winter months. During the summer months there is little difference in rainfall anywhere on the coast of the island. Due to the influence of the mountains then there are many micro-climates. It can be raining heavily in one area of the island, but just a few minutes drive away you can find tropical sunshine.
The citation of “35 days of rain a month” would be a more accurate description if it read “35 days of rain volume in ONE day”.
Whatever season you plan to come then bring waterproofs with you (including trousers) if you plan to go hiking. You can save yourself some luggage space by renting equipment on the island. YES offers a free booking service for renting waterproof gear, boots, poles, camping gear etc.
The Japanese take great pride in explaining that the country has four distinctive seasons. However, on Yakushima we could claim to have SIX! The following is a short run-down of the seasons on Yakushima.
Let’s start with the worst one! The rainy season from early June to mid-July is particularly wet with 2 to 3 times the rainfall of other months. You’d be very lucky to be on Yakushima for a few days without getting rained upon during this period. However, the island is well-equipped to deal with torrential downfalls, due to its steep granite mountains and around 150 rivers. The island rarely has a flooding problem (unlike other areas of Japan). It is still possible to go hiking in the rain as the temperature is warm and the forests look great in the rain. Make sure you have a good set of waterproofs and boots, and don’t forget to double bag everything in your backpack. However, in the event of heavy rain then consider an alternative activity as the rivers of Yakushima become dangerous and the National Parks will close. A popular hiking area that can be badly affected by the rain is Shiratani Unsuikyo due to the number of river crossings. Therefore on rainy days it is advisable to check if the trails are open and if not then change your itinierary to the Yakusugi Land area which has bridged river crossings.
Typhoons approach the island several times a year and one or two hit the island every year. The typhoon season usually begins towards the end of the rainy season and can continue up to late-October. If you come from a country unaffected by typhoons (hurricanes) then you may well be concerned about planning a trip during this time of the year. For the Japanese, typhoons are simply a fact of life and though there is always an element of risk in planning your trip during this time, if a typhoon does cause you to change your travel plans then it is customary for Yakushima hotels and activity operators to waiver any cancellation charges. If you are planning your trip to Japan during the typhoon season then consider coming to Yakushima first and NOT LAST – just in case there are ferry or flight cancellations off the island. During the typhoon season hotel changes caused by flight/ferry cancellations are a common occurrence. However, visitors who book Yakushima accommodation or car rentals with YES are always relieved to receive our support service when quick changes to bookings are required.
If you are stuck on the island during a typhoon then there is no need to panic. You won`t see the islanders trying to flee the island for fear of their lives being swept away. The greatest inconvenience is that access to/from the island will be cancelled and on the day of the typhoon you are likely to be stuck inside your hotel all day.
As we deal with typhoons every year then we request that visitors who have booked their Yakushima accommodation / tours etc with YES to first contact YES to find out what is happening at ground level rather watching the media or asking Japanese on the mainland. The Japanese media LOVE the typhoon season as it gives them easy content for their programming and they will always blow it all out of proportion. Mainland Japanese have no idea about life on the islands and they get their wisdom from the media – so go figure! Therefore, contact YES to receive accurate information. Those visitors that do not make bookings with YES then do not contact YES for storm information as the enquiry will be ignored.
The summer months are the peak season for Japanese tourists to visit Yakushima and this is for good reason. Temperatures hover around 30°C during the summer months which, combined with balmy sea breezes, makes Yakushima a much more comfortable place compared to the sweltering heat on the Japanese mainland. The humidity on Yakushima is high (usually 90%), but with the mountains considerably cooler than the coastal areas, hiking is popular and the sea, rivers and waterfalls offer a multitude of ways to have fun and stay cool. Don’t be surprised if you have the beach all to yourself as well!
The humidity begins to drop around mid-September and evenings start to feel a little cooler. Autumn is probably the driest season on Yakushima. Once the typhoon season is over, the weather can be stunning. Clear blue skies and excellent visibility mean perfect hiking conditions. Even in late October, the temperature can still reach 28°C – meaning you may still be able to swim (do expect some strange looks from any passing locals though!). Japanese hikers favour October and the hiking in November is equally good. By November, you will need a warm layer or two especially for trekking and expect the tops of the highest mountains to be under 10°C while the coast still hovers above 20 °C. The downside is that the Japanese also consider this season the ideal time for hiking on Yakushima and so you should anticipate many people on the trails. October is the busiest month of the year so prepare a few months in advance of the trip.
Winter has the largest seasonal difference in temperature and climate between the north and south of the island. The northern area is often very grey, damp and cool, while the southern area is significantly drier, sunnier and milder. The whole coastal area is sub-tropical, meaning that the temperature around the sea level of the island never falls below zero. However, Yakushima is the southernmost place in Japan where there is snow in the mountains. January and February are the coldest months when the temperature on the peaks can go as low as -10°C, but will feel much colder with the wind chill. To go hiking into the interior mountains at this time of the year requires alpine equipment (available to rent) and we strongly advise you do not attempt it without a guide as weather conditions can be very changeable and dangerous. The exterior mountains are more accessible in the winter, Mocchomudake in the south is close enough to the coast to be snow-free all winter. The popular trekking areas of Yakusugi Land and Shiratani Unsuikyo can have a light covering of snow, but are usually accessible.
Though the forests of Yakushima are mainly evergreen, when spring does come to the island it arrives with an explosion of a myriad shades of green. The island has little cherry blossom to see around the coast, but from the end of March to early April you will be able to see the ‘yamazakura’ (mountain cherry blossom) which cloaks the mountains in a beautiful pink haze. Spring is a mixture of sunshine and rainy days with lots of strong breezes and by the end of April the temperature will be around 20C. May offers beautiful conditions for hiking, but be warned if you happen to be coming during Golden Week and make sure to book everything well in advance.
| Jan | Feb | Mar | Apr | May | Jun | July | Aug | Sept | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg High ℃ | 14.4 | 15.2 | 17.5 | 21.1 | 24.3 | 26.8 | 30.4 | 30.6 | 28.7 | 24.9 | 20.9 | 16.6 |
| Record High ℃ | 25.3 | 26.1 | 9.6 | 29.8 | 31.9 | 34.8 | 35.2 | 35.4 | 34.7 | 31.0 | 30.7 | 25.7 |
| Avg Low ℃ | 8.7 | 9.1 | 11.1 | 14.2 | 17.3 | 20.7 | 23.7 | 24.2 | 22.6 | 19.0 | 14.9 | 10.6 |
| Record Low ℃ | 1.1 | 0.7 | 1.5 | 4.5 | 9.3 | 13.7 | 18.3 | 19.6 | 15.2 | 9.1 | 5.6 | 2.2 |
| Rainfall mm | 272 | 286 | 428 | 421 | 441 | 773 | 311 | 269 | 406 | 299 | 303 | 262 |
| Humidity % | 68 | 68 | 71 | 72 | 76 | 83 | 82 | 81 | 79 | 73 | 70 | 68 |