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Which Way Do Japan's Ski Slopes Face, and Does It Matter?
We measured which way every mapped run descends at 180 Japanese ski areas. At the middle one, 77% of the vertical faces north or east. That barely predicts snow quality: the weather decides what falls. Where direction matters is after the snow stops, and above all in spring.
A slope that faces away from the sun keeps its snow colder and for longer, and ski areas tend to be built that way. Worldwide, 67% of the vertical on the world’s ski runs descends toward the pole, according to a study of OpenStreetMap data (OpenSkiStats).
We measured the same thing for Japan: which way every mapped run descends, at the 180 Japanese ski areas that have eight or more runs on the map. Then we set it beside the snow we measure at each one.
Japan’s slopes face north and east
At the middle ski area, 77% of the vertical on the runs descends to the north or east. At 66% of ski areas, more than half does. North on its own is a smaller share than you might expect, 19% at the middle ski area, so most of that is east.
The names most visitors know show the spread:
| Ski area | North | East | South | West | Snow quality (of 397) |
|---|---|---|---|---|---|
| APPI | 56% | 38% | 2% | 4% | 33rd |
| Rusutsu | 44% | 42% | 8% | 6% | 126th |
| Nozawa Onsen | 30% | 10% | 13% | 48% | 134th |
| Zao Onsen | 29% | 6% | 8% | 57% | 80th |
| Hakuba Happo-One | 25% | 66% | 6% | 3% | 102nd |
| Kiroro | 21% | 2% | 6% | 71% | 24th |
| Furano | 12% | 74% | 12% | 1% | 116th |
| Niseko United | 10% | 44% | 39% | 7% | 38th |
| Myoko Suginohara | 1% | 50% | 48% | 2% | 48th |
Share of the vertical on the runs, by the direction the run descends toward.
It says little about how good the snow is
Across the 180 ski areas, the share of north- and east-facing vertical barely tracks our snow-quality score, and what small link there is runs the wrong way. Ski areas that face north and east more are, if anything, a little warmer on snowy days (a rank correlation of +0.12 with snow-day temperature), and they score a little lower on quality (−0.19).
The reason is what the score measures. It is built from the weather when it snows: the temperature, how often it rains instead, how often a big fall comes, and the wind (how the score works). That is set by the air that arrives over the mountain, not by the direction the slope faces. Kiroro is the clearest case. Seventy-one per cent of its vertical faces west, the sunniest direction in the afternoon, and it still ranks 24th of 397 for snow quality, with snow falling at −8.0 °C and rain on 6% of winter days.
So a north-facing slope does not turn a wet climate into a dry one. It protects snow that has already fallen.
Where it does matter: after the snow stops, and in spring
Direction starts to matter once the snow stops falling. On a clear day, sun on a south- or west-facing slope turns fresh snow heavy by the afternoon and crusty overnight. North-facing snow stays cold. In midwinter Japan the next storm usually resets everything within days. From late February, as the sun climbs higher, the difference between aspects grows, and for a March trip it is worth choosing terrain that faces away from the sun.
These are the ski areas where at least 60% of the vertical faces north or east, ranked by how much snow March brings:
| Ski area | March snowfall | North + east | Snow quality |
|---|---|---|---|
| Tateyama Sanroku | 112 cm | 84% | 165th |
| Okutadami Maruyama | 105 cm | 95% | 70th |
| Hakuba 47 | 99 cm | 86% | 19th |
| Tsugaike | 99 cm | 68% | 23rd |
| Hakuba Iwatake | 99 cm | 65% | 47th |
| Mitsumata (Kagura) | 97 cm | 85% | 133rd |
| Hakuba Norikura | 95 cm | 65% | 35th |
| Kagura | 95 cm | 84% | 11th |
March snowfall is the average for March over the last twelve winters. Mitsumata, Kagura and Tashiro are the three linked areas of the Kagura ski resort.
For a March trip, Hakuba 47, Tsugaike, Iwatake, Norikura and Kagura combine the three things you want: close to 100 cm of new snow in March, most of the terrain facing north or east, and snow-quality scores in the top 50.
The best of both
These ski areas have at least 75% of their vertical facing north or east and rank in the top 50 for snow quality:
| Ski area | North + east | Snow quality | Snow-day temperature | Typical winter | Worst of 12 |
|---|---|---|---|---|---|
| Tengendai Kogen | 76% (north 74%) | 9th | −7.8 °C | 379 cm | 151 cm |
| Kagura | 84% | 11th | −6.7 °C | 542 cm | 241 cm |
| Tashiro (Kagura) | 82% | 12th | −7.1 °C | 447 cm | 241 cm |
| Shiga Kogen Kumanoyu | 92% | 14th | −8.9 °C | 333 cm | 214 cm |
| Okushiga Kogen | 88% | 18th | −8.2 °C | 333 cm | 214 cm |
| Hakuba 47 | 86% | 19th | −4.5 °C | 668 cm | 380 cm |
| Sapporo Kokusai | 84% | 25th | −7.8 °C | 331 cm | 209 cm |
| APPI | 94% | 33rd | −5.2 °C | 377 cm | 167 cm |
| Blue Resort Norikura | 97% | 36th | −7.7 °C | 317 cm | 134 cm |
| Iizuna Higashi Kogen | 87% | 37th | −5.1 °C | 357 cm | 230 cm |
| Hachimantai Shimokura | 90% | 46th | −5.3 °C | 329 cm | 167 cm |
| Asarigawa Onsen | 92% | 49th | −4.9 °C | 293 cm | 209 cm |
Of the 180 ski areas, only two have at least 60% of their vertical facing due north and also rank in the top 50 for snow quality: Tengendai and Shiga Kogen Kumanoyu. Tengendai’s runs descend 74% northward, where the typical Japanese ski area has a fifth, and it ranks 9th for snow quality. Kumanoyu is 65% north-facing and the coldest on this list. Tengendai’s catch is its floor: in its leanest winter it had 151 cm. Hakuba 47 is the opposite trade, a little less cold, but with one of the deepest floors in the country.
How this was measured
Slope direction comes from the runs mapped on OpenStreetMap, as processed by OpenSkiMap (© OpenStreetMap contributors, ODbL 1.0). We split each run into short segments and keep the ones that go downhill. Each segment counts toward the compass direction it descends toward (north, east, south or west), weighted by how much height it loses, so steep pitches count for more than flat traverses. This is the same approach OpenSkiStats uses. Only ski areas with eight or more mapped runs are included, 180 in all. Niseko’s figures are for the whole Niseko United area, which the map draws as one ski area.
This measures the mapped runs, not the whole mountain, and how finely ski areas are mapped varies. We have no measurement of how snow differs between aspects at a given ski area. What is here is the shape of the terrain and the weather when it snows, not a direct measurement of snow on each slope.
Snow quality, snow-day temperature and rain use our snow-quality score for Japan’s 397 ski areas (details). Snowfall adds up each day’s snowfall over each of the last twelve winters (December to March, 2014/15 to 2025/26) using the ERA5 reanalysis. March snowfall is the average for March over the last twelve winters. Neighbouring ski areas can share one cell of the model’s grid, which is why Hakuba 47, Tsugaike and Hakuba Iwatake have the same snowfall figures. The model understates mountain snow (details), so use the figures to compare ski areas.
The rank correlations are Spearman correlations across the 180 ski areas. A value near zero means the two measures barely move together.
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