📷 Gassan
Asia
Gassan
Off-season
Conditions data updated Sat, Jul 4, 04:02 PM UTC · informational only
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Closed for Season
Weather data is still collected for informational purposes.
Last Snowfall
--
Past 24 Hours
0cm
Past 48 Hours
0cm
Past 10 Days
0cm
14-Day Forecast
0cm
Snow Depth
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Overview
Gassan is a ski resort in Asia, Japan, currently closed for the season. Today's SnowSure™ Score is 10/100. Conditions last updated 2026-07-04 16:02 UTC.
Resort Guide
Gassan Ski Resort is located in Yamagata Prefecture, Japan, on the slopes of Mount Gassan. Known for its unique spring and summer ski season due to heavy winter snowfall, the resort typically operates from April to July. Gassan offers a relaxed atmosphere with natural, ungroomed slopes, catering primarily to intermediate and advanced skiers seeking a distinctive late-season experience. Key amenities include rental services and a simple base lodge, with the resort standing out for its deep snowpack and scenic mountain views.
Gallery
Click to expand • 5 total photos
Terrain & lifts
Resort-reported stats for Gassan
Lifts
3
Skiable area
2 ac
Longest run
10 km / 6.2 mi
Runs by difficulty(4 total)
Beginner
1
20% of terrain
Intermediate
2
40% of terrain
Advanced
1
40% of terrain
Run counts estimated from resort-reported totals and terrain mix.
Lift fleet
- Double chair1
- Surface lift2
Resort Info
Ski passes
No ski pass found
Access tiers change by season — confirm benefits on the pass operator's site.
Top Après Ski
Unable to determine top apres ski place for this resort.
Not operating — season has ended
SnowSure scores and forecasts below are for planning and reference only while the resort is closed.
Depth
Resort closed — no current ski-base depth.
Recent
No new snow has fallen in the past week.
Forecast
The 14-day snow outlook is currently unavailable.
Historic
Season-to-date snowfall is not available for comparison, while the 5-year average to date stands at 710cm.
Closed for the season · Data updated Sat, Jul 4, 04:02 PM UTC · informational only
Snow Summary
Updated Jul 4, 2026 at 4:02 PM
Historical data from Open-Meteo archive • Forecast from ECMWF IFS model
Snowfall Forecast Maps
Japan (Tohoku & Niigata) region
Current Conditions
Reported Sat, Jul 4, 04:02 PM UTC
Base
1235m
Temp
12.9°C
Wind
4.5km/h
Snow Depth
--
14-Day Forecast
0cm
Mid-Mountain
1453m
Temp
--°C
Wind
5km/h
Snow Depth
--
14-Day Forecast
0cm
Summit
1670m
Temp
10.1°C
Wind
4.5km/h
Snow Depth
--
14-Day Forecast
0cm
Local Reports
0 reportsDaily Snowfall Forecast by Model
Black line = verified SnowSure™ blend (not a simple average). Weights update weekly from measured snowfall at SNOTEL stations and resort reports.
SnowSure™ blend — verified model weighting
The black line is not a simple average. For Gassan (japan), we combine seven global weather models using weights learned from daily forecast verification — comparing each model's prediction to measured snowfall (SNOTEL, resort reports, ERA5).
- 1.Horizon buckets: days 1–3, 4–7, and 8–14 each get separate weights — short-range skill differs from long-range.
- 2.Regional calibration: weights come from verified error in this geography (Rockies, Alps, Japan, etc.), recalculated weekly.
- 3.Ground truth only: we never grade a forecast against another model — only against measured snow.
Building verification history for this resort.
How we verify forecasts →Hourly Forecast Detail
AM / PM / Night breakdown with wind and freezing level
NWP models refresh up to 4× daily · Last synced Jul 4, 4:02 PM
Sun, Jul 5 17 / 10 | Mon, Jul 6 14 / 91.7mm | Tue, Jul 7 16 / 90.7mm | Wed, Jul 8 17 / 1114.6mm | Thu, Jul 9 19 / 132.2mm | Fri, Jul 10 19 / 143.6mm | |||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Period | AM | PM | Night | AM | PM | Night | AM | PM | Night | AM | PM | Night | AM | PM | Night | AM | PM | Night |
| Snow (cm) | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| Precip (mm) | 0 | 0 | 0 | 0 | 0.9 | 0.8 | 0 | 0.3 | 0.4 | 2.8 | 9.4 | 2.4 | 1 | 0.9 | 0.3 | 2.1 | 1.5 | 0 |
| Temp (°C) | 14 | 16 | 11 | 12 | 13 | 10 | 13 | 15 | 11 | 15 | 17 | 13 | 16 | 19 | 14 | 17 | 19 | 15 |
| Wind (km/h) | 6 | 8 | 6 | 8 | 10 | 7 | 6 | 5 | 5 | 3 | 2 | 3 | 6 | 3 | 2 | 11 | 11 | 3 |
| Gusts (km/h) | 21 | 26 | 18 | 27 | 33 | 22 | 21 | 21 | 16 | 13 | 19 | 13 | 31 | 34 | 22 | 38 | 35 | 24 |
14-Day Snow Forecast by Model
Summit elevation (1670m)
10-Day Forecast
Sun
5
☁️
16.8°
10°
8 km/h
Mon
6
🌧️
14°
9.2°
12 km/h
Tue
7
🌧️
15.5°
8.9°
8 km/h
Wed
8
🌧️
17.1°
10.8°
4 km/h
Thu
9
🌧️
19°
12.6°
6 km/h
Fri
10
🌧️
19.2°
13.5°
13 km/h
Sat
11
🌦️
16.1°
13°
8 km/h
Sun
12
🌦️
15.2°
12.6°
6 km/h
Mon
13
🌧️
17.9°
12.3°
5 km/h
Tue
14
🌧️
17.7°
12.1°
14 km/h
Summit elevation (1670m) • ECMWF model
Season vs Historic
Updated Sat, Jul 4, 04:02 PM UTC
0cm
Season Total
This Season to Date
—
vs 5-Year Avg
Off-season · 710cm full-season avg
—
vs 30-Year Avg
Off-season · 710cm full-season avg
710cm
5-Yr Avg by Now
Snowfall over the past five years has been significantly above the long-term 30-year average, with the recent 5-year average reaching 787.7 cm compared to the 30-year average of 588.2 cm. The current season's snowfall is 2% higher than the recent 5-year average and 37% above the 30-year average, indicating a sustained period of above-average snowfall. Notably, the 2020 season was an outlier with substantially lower snowfall, but subsequent years have rebounded strongly, maintaining this elevated trend. Overall, the data reflects a marked increase in snowfall in recent years relative to historical norms.
Gassan Snow History
Average annual snowfall is 595cm with an average of 118 snowfall days per season. The table below shows monthly averages across 30 seasons of archive data (modeled snowpack at mid-elevation).
| Month | Avg Snowfall | Snowfall Days | Avg Base Depth | Max Base Depth | Biggest Snowfall |
|---|---|---|---|---|---|
| November | 40.3cm | 10 days | 4cm | 17cm | 10.2cm |
| December | 150.9cm | 25 days | 44cm | 86cm | 16.3cm |
| January | 178.7cm | 29 days | 125cm | 160cm | 18cm |
| February | 116.9cm | 25 days | 167cm | 187cm | 13.6cm |
| March | 83.9cm | 21 days | 170cm | 191cm | 13.2cm |
| April | 24cm | 8 days | 113cm | 162cm | 8.6cm |
| May | 0.3cm | 0 days | 13cm | 61cm | 0.7cm |
Source: SnowSure archive · Open-Meteo ERA5 reanalysis at mid-elevation. Depth is modeled, not resort-reported.
Season at a Glance
Next season(2025-26)
Opens Apr 10, 2026
Multi-season averages will appear once SnowSure has tracked more than one full season.
Best Months to Visit
January
Peak Powder
February
Peak Powder
March
Good
December
Good
Note: Based on typical powder season patterns for this region.
