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La Nina Japan 2025 Winter
October 2024 forecast update for 2024/25 season in the Nagano resorts and Myoko Kogen
First, a little bit of explanation of how we come to the following conclusions. We rely on a variety of sources – both formal (JMA, NOAA and other weather bodies) and informal (resort locals and knowledgeable pundits like those on ski.com.au), as well as my personal experience of the region over 30 years. Working with all these there tends to be a diversity of opinion but we do our best to collate it all into something intelligible.
Secondly, as much as we might not like (or many try to deny it), the effects of climate change are becoming clearer. And that means that traditional weather models are not as reliable anymore. Another La Niña this year (which seems to be on the cards ATM) would be the fifth event in just five years (see below) — well above the average of one every four years, and a frequency only previously seen twice since 1900. So there’s a bit of presumption and guesswork based on the last 3-5 seasons.
Lastly, this is our personal perspective on this winter weather, based on the above and could be completely wrong! So please take it as general advice only and don’t do all your bookings based upon it.
Last week we seemed to reach an inversion point where the weather suddenly cools. One day you’re wearing shorts and a t-shirt and then you’re suddenly rugging up at night. The change of season usually occurs around early-mid October, where the stationary boundary forms and moves south, separating the warm summer temperatures from the cooler autumn, along with the return of northerly low pressure & cold fronts that characterise the cooler seasons. However, after a couple of nights of colder temperatures, things started warming up again and it was even a bit muggy. Things can change fast however and the night after I wrote this we saw the first dusting of snow on Mount Myoko, Shiga Kogen and other parts of the Japan Alps. There was more than a dusting up north on Hokkaido though.
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Here’s a recent video looking at the forecast movement of the weather from here through to December
Further reading: Nagano Snow Report and Weather Conditions | Nagano Webcams
More about La Nina Japan 2025 Winter
Otherwise, looking first at the El Niño/La Niña phenomenon that has a major impact on winter weather, not in Japan but across the globe. Both the US weather authorities and the Japan weather agency have announced that the La Niña phenomenon is almost certain. The NOAA has claimed on Oct. 10 that, “La Niña is favored to emerge in September-November (60% chance) and is expected to persist through January-March 2025”. Next is the dipole mode phenomenon in the Indian Ocean, but this winter, you can see the trend of negative dipole phenomenon. A positive dipole is a warm winter factor. Based on all of these, this winter, the westerly winds are likely to snake from northwest to southeast near Japan, and the cold weather in Siberia is likely to flow into Japan, which means a cold and winter trend. That’s the good, hopeful news.
FYI Seasonal forecasts can be found on the JMA (Japan Meteorology Agency) site, and here are the latest screenshots for temperatures and then snowfall.
Temperature wise, for central Japan it looks slightly less promising (possibly just below regular) than northern Honshu and Hokkaido (just above regular), but snow fall looks quite promising. However, I want to dig into those disparities a little more.
Let’s look at the trend for Japan in recent years:
20-21 & 23-24 El Niño / Positive dipole mode → Warm winter with under-average and uneven falls
21-22-23 La Niña / Negative dipole mode → Cold temperatures and heavy, even record snowfalls.
However, when looking at the average temperature distribution near Japan in January during these seasons, during El Niño it’s blustery, but also during La Niña it’s slightly higher than average.
The war on snow in Akakura Onsen.
Observations of recent winters in Nagano during La Niña
Under the old weather models westerly winds usually brought cold weather and heavy snow falls to the region but, more recently, sometimes there was unseasonably warm periods in-between heavy falls and sometimes heavy rain. This is because the high pressure systems pushing cold winds from the north around Siberia and causing a lake sea effect as it crosses the Japan Sea have actually been declining in recent years. After the nor-westerly winds bring cold fronts into Japan, it is now taking longer to accumulate strength for the next cold front. This therefore causes an influx of warmer weather during the cold front accumulation period, thereby oft bringing unseasonably warmth and heavy rain.
Additionally, average global temperatures in January are rising year after year, especially in the last few years. With this warming, the cold weather in Siberia is becoming more difficult to build up, plus the cold weather buildup period is getting longer. Sadly this is a trend that seems to continue and quite likely worsen.
Looking at these in total, here are my predictions for the next winter’s weather in Nagano
1. There will be numerous strong cold weather flows into Nagano and western Japan over the season. If you are on the slopes during these times you’ll be having some great powder days.
2. However, as in recent seasons, there will likely be an influx of reasonably intense warmth between these falls. This can bring sunny, warm days quite possibly rain. These days will not be quite as good BUT it should almost definitely have a better base than last season and not be rock hopping.
3. Thanks to the strong cold regular falls, Nagano will have 2-5 metres more snow than last season, as well as a better base. Just that falls could well be irregular, and it may rain occasionally even in the middle of winter.
4. For those heading out into the backcountry, snowfall and conditions are prone to instability with some slab effect after rain. Always check conditions at https://nadare.jp/ first, be careful out there and make sure your insurance is valid. Local guides can be found and bookings made at https://myokokogen.org.
5. Spring is likely to be generally early as La Niña weakens. Many ski areas that have been traditionally open until Golden Week in May (such as Shiga Kogen, Seki Onsen, Akakan, Nozawa Onsen, etc.) may not have enough snow to keep open. It will be heavily dependent on heavy falls and a decent base.
Once again, please understand that this is just an amateur’s personal opinion, not official forecasts and predictions. Fingers crossed that some of my doom scenarios are wrong.
Help us out!
Note: During the season I write regular snow reports on Myoko/Madarao. You can also find weather and forecasts for the following Nagano ski resorts – Hakuba, Nozawa, Shiga Kogen. If you like my work please do consider donating a little something here to keep this nonsense going. You can also book your ski shuttles here, private transfers here, or your accommodation as below
Book now to get the best La Niña Japan deals!
Can’t find what you want? Send us a accommodation request or ask a question.
Note to other website owners. Whilst we know you and your guests/clients/visitors will be excited to read about La Nina Japan in 2024/25, if you choose to reference some or all of the above you must ensure that you include the acknowledgment to us. Thank you!
La Niña Japan, La Nina Japan
The post Nagano La Nina Japan 2025 Winter Myoko first appeared on Nagano Japan.
]]>The post La Nina Japan 2025 Winter | Nagano | Myoko first appeared on Nagano Japan.
]]>This is our June 24 update
La Nina Japan 2025 Winter
Our first forecast update for 2024/25 season in the Nagano resorts and Myoko Kogen
It’s the heat of summer here, but still time to crack out the crystal ball and see what the long term snow forecast could be for this 2024/25 season in Nagano and surrounding areas with La Niña Japan 2025!
Typically, during La Niña years, Japan experiences cooler and wetter conditions in winter, which can influence weather patterns and potentially affect, apart from the ski industry – agriculture, fisheries and even societal activities. However, the exact nature and intensity of these impacts can vary from year to year and area to area. At this very early stage the forecast is good with a 60% chance of a La Niña event.
Get your Nagano snow reports and weather updates for 24/25 season here!
Some Observations
On July 10, the Japan Meteorological Agency announced its “El Niño Monitoring Bulletin.” According to recent data, the current situation is normal, with neither El Niño nor La Niña occurring, but it is predicted that there is a high possibility of a La Niña occurring in the fall. The probability of heavy snowfall in the 24-25 season has increased exponentially with this forecast.
As a result of June observations, the difference between the sea surface temperature and the reference value in the El Niño monitoring area was -0.2°C, down from 0°C in May. The sea surface temperature in the equatorial Pacific Ocean was higher than normal in the west and lower than normal in the east. Therefore, it was confirmed that the overall condition is continuing to be normal. The atmosphere-ocean coupled model, a numerical model for simulating the interaction between the atmosphere and the ocean, predicts that the trade winds will become stronger in the western and central parts of the equatorial Pacific Ocean, and cold water will become even stronger in the central and eastern parts, so that the future outlook is that the temperature will remain close to or lower than the reference value through the fall. As a result, the Japan Meteorological Agency has estimated the possibility of a La Niña phenomenon occurring to be 60%.
When the La Niña phenomenon occurs, as mentioned above, the sea surface temperature in the equatorial Pacific Ocean drops, changing the atmospheric circulation pattern and increasing the probability of the Siberian high pressure system strengthening in winter. This makes it easier for cold air to flow into the vicinity of Japan, and as this cold air passes through Japan, it forms many clouds containing water vapor on the warm sea surface, and these collide with Japan’s mountainous regions, causing heavy snowfall. In addition, when the La Niña phenomenon occurs, the position and strength of the westerly winds change, making it easier for cold air to strengthen over the Japanese archipelago. This increases the possibility of increased snowfall.
Of course, heavy snowfall can sometimes be disastrous, so it’s not something to be happy about in that context. But it’s definitely good news if you’re a skier or snowboarder.
Further reading: Nagano Snow Report and Weather Conditions | Nagano Webcams
Some Observations for La Nina Japan 2024/25 (Nagano & Myoko)
At this stage we don’t have enough evidence to know what might happen specifically in Central Japan. There are many other factors that are considered when developing a winter forecast, but this year the early considerations are pointing to a promising pattern. Usually La Niña will bring above-average conditions in Myoko Kogen and Hakuba but maybe not as quite as much further inland, such as in Shiga Kogen (but still excellent!). The resorts that are the common local winners are those closer to the coast like Hiuchi Charmant, Arai, Cupid Valley and Seaside Valley.
The war on snow in Akakura Onsen.
There’s a correlation of sorts between La Nina & snowfall in some parts of Japan according to data between 1994/95 to 2015/16:
Myoko Kogen
Average 1487cm
La Nina: 1756cm
El Nino: 1308cm
Neutral: 1332cm
Yuzawa
Average 1369cm
La Nina: 1560cm
El Nino: 1121cm
Neutral: 1320cm
The worst La Nina years in this period came in around 1450cm. The best La Nina was 1876cm for Yuzawa, and 2324cm for Myoko Kogen. Both these ski resort areas lie either side of northern Nagano.
Japanese media are reporting that La Nina can cause abnormally heavy snow. Whilst not guaranteed there is a reasonable correlation. The emergence of La Niña Japan was also observed from December 2005 to February 2006, when around 150 people died as a result of heavy snow across Japan. Snows were also heavy in another recent occurrence of La Niña in 2011/12.
A great 2024/25 Nagano winter coming up we hope!
The Japan Meteorological Agency’s expectation that the La Niña Japan winter 2024/25 may appear aligns with the U.S. National Oceanic and Atmospheric Administration which upgraded it’s forecast to a 79% chance of the phenomenon appearing during the upcoming Northern Hemisphere winter.
We’ll be updating this page as further forecasts are released between August and November 2024
Book now to get the best La Niña Japan deals!
Can’t find what you want? Send us a accommodation request or ask a question.
Note to other website owners. Whilst we know you and your guests/clients/visitors will be excited to read about La Niña Japan in 2024/25, if you choose to reference some or all of the above you must ensure that you include the acknowledgment to us. Thank you!
The post La Nina Japan 2025 Winter | Nagano | Myoko first appeared on Nagano Japan.
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