A Historic El Niño Is Forecast. Here Is What the Last Big One Did to Japan's Snow.
NOAA gives a very strong El Niño better than a 90% chance this winter. We measured every Japanese ski area across the last 12 winters: El Niño winters ran 88% of normal, and the strongest one on record left Japan at 63%. But Hakuba held 92% of its average that winter while Niseko fell to 57%.
On 10 September the US Climate Prediction Center put out an El Niño Advisory: a greater than 90% chance of a very strong event through the coming Northern Hemisphere winter, and a 75% chance that October–December runs stronger than anything measured since 1950.
We do not forecast snow, and nothing here is a forecast. What we can do is measure. We have the daily snowfall at all 3,065 ski areas on earth for the last 12 winters, on one method. So the question “what does an El Niño winter actually do to Japan?” has an answer that does not depend on anyone’s opinion.
The last 12 winters in Japan, with the El Niño index beside them
ONI is the Oceanic Niño Index for December–February, published by NOAA. Above +0.5 is El Niño, below −0.5 is La Niña. The snowfall column is the average December–March total across 393 Japanese ski areas, as a share of the 12-winter average.
| Winter | ONI | Japan’s snowfall | Share of normal |
|---|---|---|---|
| 2014/15 | +0.73 | 279 cm | 98% |
| 2015/16 | +2.50 | 179 cm | 63% |
| 2016/17 | −0.08 | 311 cm | 109% |
| 2017/18 | −0.71 | 322 cm | 113% |
| 2018/19 | +0.99 | 273 cm | 96% |
| 2019/20 | +0.71 | 238 cm | 84% |
| 2020/21 | −0.99 | 282 cm | 99% |
| 2021/22 | −0.76 | 342 cm | 120% |
| 2022/23 | −0.55 | 281 cm | 99% |
| 2023/24 | +1.84 | 283 cm | 100% |
| 2024/25 | −0.46 | 349 cm | 122% |
| 2025/26 | −0.39 | 275 cm | 97% |
The relationship is real and it is not weak. Across these 12 winters the correlation between the ONI and Japan’s snowfall is −0.73: the warmer the tropical Pacific, the less snow Japan got.
| Average share of normal | |
|---|---|
| El Niño winters (5) | 88% |
| Neutral winters (3) | 110% |
| La Niña winters (4) | 108% |
What the strongest El Niño actually did
2015/16 holds the ONI record in this set at +2.50, and it was Japan’s worst winter of the 12 by a wide margin: 63% of normal. That is not an average hiding a few disasters. 365 of the 393 ski areas we measure came in below their own average, and 241 of them below 70% of it.
Where it landed mattered more than whether it landed.
| Region | Ski areas | 2015/16 share of normal | Below 70% |
|---|---|---|---|
| Hokkaido | 86 | 81% | 22 |
| Tohoku | 89 | 63% | 61 |
| Chubu, Joetsu and Nagano | 165 | 67% | 109 |
| Western Japan | 53 | 44% | 49 |
Western Japan effectively lost the winter — Gozaisho came in at 4% of its average, Kutsuki at 10%, Grandsnow Okuibuki at 11%.
The part that will surprise you: Hakuba beat Niseko that winter
The resorts people name are not affected in the same order as the regions they sit in.
| Resort | Typical winter | 2015/16 | 2023/24 |
|---|---|---|---|
| Hakuba Happo-One | 414 cm | 92% | 102% |
| Hakuba Goryu & Hakuba47 | 414 cm | 92% | 102% |
| Furano | 220 cm | 93% | 93% |
| Shiga Kogen | 255 cm | 84% | 116% |
| Rusutsu | 212 cm | 73% | 98% |
| Nozawa Onsen | 450 cm | 67% | 103% |
| Myoko Suginohara | 357 cm | 65% | 110% |
| Kiroro | 331 cm | 63% | 106% |
| Niseko Grand Hirafu | 289 cm | 57% | 97% |
| Naeba | 446 cm | 54% | 101% |
| Zao Onsen | 258 cm | 50% | 113% |
| APPI Kogen | 377 cm | 44% | 110% |
Niseko, the name everyone books first, lost 43% of its snow that winter. Hakuba, 1,000 km south, lost 8%. A strong El Niño weakens the winter monsoon that drives Hokkaido’s sea-effect snow; the Nagano ranges keep taking orographic snowfall from what is left.
The honest counterexample
2023/24 was also a strong El Niño — ONI +1.84, the second highest in this set — and Japan came in at 100% of normal. Zao got 113% of its average that winter. Whatever happened in 2015/16, “strong El Niño” on its own did not repeat it.
Two very strong El Niños, one catastrophic winter and one completely ordinary one, is the whole sample. Anyone telling you with confidence what this winter will bring is filling that gap with something other than data.
What we would actually plan around
Not the forecast — the floor. Every resort page on this site now carries the worst of its last 12 winters, which is the number that decides whether a trip booked a year out still works.
- Hakuba Happo-One: worst winter of 12 was 301 cm, against a 414 cm average
- Nozawa Onsen: worst was 301 cm, against 450 cm
- Niseko Grand Hirafu: worst was 166 cm, against 289 cm
- Zao Onsen: worst was 129 cm, against 258 cm
A resort whose bad winter still delivers 300 cm is a different proposition from one whose bad winter delivers 129 cm, and that gap does not show up in the season averages every other site quotes.
If you are booking from Australia or New Zealand off the back of a thin season at home, that is the column to read.
How this was measured
Snowfall is the December–March total at each ski area’s coordinates, from ERA5 reanalysis via the Open-Meteo Historical Weather API, summed on Japan time and averaged over the 12 winters from 2014/15 to 2025/26. The same method is used for all 3,065 ski areas on this site, which is what makes the comparison possible. ERA5’s grid is 10–30 km across, so absolute totals differ from what a resort’s own snow stake reports; the year-to-year ratios shown here are what the method is good for.
ONI values are NOAA’s published Oceanic Niño Index for December–February. The outlook is the Climate Prediction Center’s ENSO Advisory of 10 September 2026. JAPANSNOWLINE publishes no forecast of its own — for conditions before you travel, check the Japan Meteorological Agency and the resort.
Book the trip
We do not take bookings. These are the sites Japanese ski accommodation actually sits on.
Contains advertising. We may earn a commission on bookings made through Rakuten.
Keep reading
Other guides built from the same dataset.