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Gassan ski resort

Asia

Gassan Snow Forecast

Likely closed for the season (no closing date on record)

Likely closed for the season (no closing date on record)

Best months to book: January, February, March · 30-yr snow record

Likely closed for the season (no closing date on record)

Weather data is still collected for informational purposes.

Last Snowfall

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Past 24 Hours

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Past 48 Hours

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Past 10 Days

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7-Day Forecast

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Snow Depth

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Updated: Oct 13, 11:02 PM•Weather at base: 1,235m
SnowSure™ ScoreWhen to book
Likely closed for the season (no closing date on record)

Gassan is closed for the season. Here is when it is usually best to book.

Best months to book: January, February, March.NovDec1Jan2Feb3MarAprMay

Best months to book

  1. #1January179cm avg
  2. #2February117cm avg
  3. #3March84cm avg

Ranked on 30-year snowfall and base-depth record. The live score returns when the lifts turn.

Snow Summary

1,526m · mid-upper

Updated Oct 13, 2026 at 11:02 PM

0cm
24h
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Past 10d
7-Day Forecast
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Prev10d
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Now14
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T15
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F16
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S17
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S18
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M19
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T20
Days 8–14 and every model are in Pro.Unlock with Pro
Past
Today
Forecast

Hourly Forecast

14 Wed
8° / 2°
15 Thu
7° / 0°
16 Fri
8° / 3°
17 Sat
7° / 1°
18 Sun
11° / -1°
19 Mon
11° / 6°
20 Tue
9° / 5°
Days 8–14 and every model are in SnowSure Pro.Unlock with Pro
AMPMNightAMPMNightAMPMNightAMPMNightAMPMNightAMPMNightAMPMNight21 Wed22 Thu23 Fri24 Sat25 Sun26 Mon27 Tue
Conditions🌧️🌧️🌧️🌤️☁️🌤️🌧️🌧️🌤️🌧️☀️🌧️⛅🌤️🌤️🌧️🌧️🌧️🌤️☁️🌧️
rainheavy drizzlelight drizzlemostly clearcloudymostly clearlight drizzlelight rainmostly clearlight drizzleclearlight drizzlesome cloudsmostly clearmostly clearlight drizzlerainlight drizzlemostly clearcloudylight drizzle
Summit1,670 mModeled
Temp°C8°7°5°4°6°3°6°7°4°4°5°1°5°11°4°10°9°7°6°8°6°
Feels like°C6°4°2°0°2°-1°3°3°1°0°1°-2°2°8°1°7°6°5°3°6°3°
Snowcm·····················
Precipmm13.07.93.40.20.10.91.16.10.60.4·0.5··0.24.913.52.6··0.8
Windkm/h1113101314121715101013777314156727
Mid-mountain1,453 mModeled
Temp°C9°8°6°5°8°4°8°8°5°5°7°3°7°12°5°11°10°8°7°10°7°
Feels like°C7°6°4°1°4°1°4°5°2°2°3°0°4°10°3°9°8°7°5°7°5°
Snowcm·····················
Precipmm13.07.93.40.20.10.91.16.10.60.4·0.5··0.24.913.52.6··0.8
Windkm/h1113101314121715101013777314156727
Base1,235 mModeled
Temp°C11°9°8°7°9°5°9°9°6°7°8°4°8°13°6°13°12°10°9°11°9°
Feels like°C9°7°5°3°6°2°6°7°4°4°5°2°5°12°5°11°10°8°7°9°7°
Snowcm·····················
Precipmm13.07.93.40.20.10.91.16.10.60.4·0.5··0.24.913.52.6··0.8
Windkm/h1113101314121715101013777314156727
Humidity%959997766494839795836694606180909993775084
0°C linem—————————————————————
Sunhours

Freeze line is the height where rain turns to snow. Plain: straight from the models. Marked ○: estimated from temperature. Sun is hours of actual sunshine, not day length; blank means we have no reading.

Forecast Range · SnowSure Pro

Every model for Gassan, side by side for 14 days

Where the models agree, where they split, and which one has been most accurate here.

Unlock with Pro

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 →

Snowfall Forecast Maps

Japan (Tohoku & Niigata) region

14 Day map is in SnowSure ProUnlock with Pro

El Niño Outlook · Winter 2026-27

Gassan El Niño rank & forecast

Gassan ranks #402 of 488 SnowSure resorts — Tier E, −14% in strong El Niño winters.

Tier E — Deep timing play — aim late winter: Strong El Niño winters ran clearly below this resort’s own baseline (≤ −8%). Still skiable — schedule late season; one storm cycle can beat the climatology.

#402 of 488Tier E — Deep timing play — aim late winter

Strong-event signal: −14% vs this resort's 30-yr avg

In the three strongest El Niño winters on record ('97-98, '15-16, '23-24), Gassan averaged -14% versus its own 30-year snowfall baseline. Historically this is a timing play rather than a reason to stay home: aim for late winter (February–March) in winter 2026-27. Analog winters: '97-98 -35%, '15-16 -34%, '23-24 +26%. A pattern, not a promise.

'97-98 −35%'15-16 −34%'23-24 +26%

ENSO seasonal analog

History · not a forecast

In 10 past El Niño winters at Gassan, ERA5 season snowfall median was 508 cm (200 in), about 5% below this resort’s long-term median. This is a historical analog from reanalysis — not a prediction of this winter’s storm track.

Prevailing ONI

El Niño

JAS 2026 · ANOM +2.16°C

Analog season median

508cm

10 El Niño winters · 5% below median

All-season median

537cm

Across 30 ERA5 seasons (2026-27)

PhaseSeasonsMedianp25–p75Recent analogs
El Niñocurrent10508cm419cm – 666cm2023, 2019, 2018, 2015, 2014, 2009
La Niña12561cm510cm – 706cm2022, 2021, 2020, 2017, 2011, 2010
ENSO-neutral8550cm486cm – 771cm2025, 2024, 2016, 2013, 2012, 2003

Season snowfall from Open-Meteo ERA5 reanalysis (~9 km). ENSO phase from NOAA CPC Oceanic Niño Index. Relative phase differences are more trustworthy than absolute cm totals. Source: NOAA CPC Oceanic Niño Index + Open-Meteo ERA5 via SnowSure season archive.

Local Reports

0 reports

How accurate is this forecast?

We verify every forecast against what actually fell — see the model-by-model results.

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Frequently asked questions about Gassan

How much snow is Gassan getting this week?
No significant snow is forecast at Gassan over the next 7 days.
What is the 14-day snow forecast for Gassan?
The full 14-day forecast for Gassan — the SnowSure™ blend and every model we track, day by day — is part of SnowSure Pro. The first 7 days are free on this page.
How accurate are SnowSure forecasts for Gassan?
We verify every forecast against what actually fell and publish the results — see our forecast verification pages for model-by-model accuracy, updated continuously.