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Tier C — ENSO-proof

North America

Projected to open October 25, 2026

Best months to book: April, March, February · last season + 30-yr record

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Projected to open Oct 25

Weather data is still collected for informational purposes.

Last Snowfall

Oct 16

today

Past 24 Hours

1cm

Past 48 Hours

1cm

Past 10 Days

13cm

7-Day Forecast

0cm

Snow Depth

Updated: Oct 16, 12:00 PM•Weather at base: 2,830m

SnowSure™ Score2025-26 season

Projected to open Oct 25

Keystone is projected to open October 25, 2026. Here is when it is usually best to book.

Best months to book

#1April51cm avg · last season 24.8
#2March41cm avg · last season 25.9
#3February36cm avg · last season 32.4

Best weeks to book

#1 5 Apr – 11 Apr · last season 23.4
#2 29 Mar – 4 Apr · last season 25
#3 1 Mar – 7 Mar · last season 31

Ranked on 25% last season's SnowSure score (2025-26) · 75% 30-year snowfall and base-depth record. The live score returns when the lifts turn.

Snow Summary

Updated Oct 16 at 12:00 PM

Freezing line

13cm

Season

5cm

Past 10 days

8cm

48h

1cm

24h

0cm

Today

1cm

Next 6 days

Days 8–14 · Pro

Seasontotal

Wed14

Thu15

14 daystotal

—

SunOct 4

Mon5

Tue6

Wed7

Thu8

Fri9

Sat10

Sun11

Mon12

Tue13

TODAY16

Sat17

Sun18

Mon19

Tue20

Wed21

Thu22

Fri23

Sat24

Sun25

Mon26

Tue27

Wed28

Thu29

Freezing line

Days 8–14 and every model are in SnowSure Pro.Unlock with Pro

Hourly Forecast

	16 Fri 6° / -10°			17 Sat 8° / -7°			18 Sun 7° / -6°			19 Mon 4° / -7°			20 Tue 6° / -6°			21 Wed 8° / -7°			22 Thu 5° / -4°			Days 8–14 and every model are in SnowSure Pro.Unlock with Pro
	AM	PM	Night	AM	PM	Night	AM	PM	Night	AM	PM	Night	AM	PM	Night	AM	PM	Night	AM	PM	Night	23 Fri	24 Sat	25 Sun	26 Mon	27 Tue	28 Wed	29 Thu
Conditions	☀️	☀️	☀️	☀️	☀️	☀️	☁️	☁️	☀️	⛅	🌧️	☀️	🌤️	⛅	☀️	☀️	🌤️	☁️	☁️	🌧️	☁️	❄️	❄️	☀️	☀️	🌤️	🌤️	☀️
	clear	clear	clear	clear	clear	clear	cloudy	cloudy	clear	some clouds	light drizzle	clear	mostly clear	some clouds	clear	clear	mostly clear	cloudy	cloudy	light drizzle	cloudy	light snow	light snow	clear	clear	mostly clear	mostly clear	clear
Summit3,782 mModeled
Temp°C	-5°	4°	-5°	-1°	7°	-2°	0°	7°	-1°	0°	5°	-1°	-1°	5°	-1°	0°	5°	-1°	1°	5°	0°	-1°	-4°	-5°	-4°	-4°	-6°	-6°
Feels like°C	-8°	1°	-11°	-6°	3°	-8°	-5°	2°	-8°	-4°	0°	-8°	-4°	1°	-7°	-4°	2°	-7°	-3°	-1°	-5°	-4°	-9°	-8°	-7°	-8°	-9°	-9°
Snowcm	·	·	·	·	·	·	·	·	·	·	·	0.1	·	·	·	·	·	·	·	0.1	0.4	5.9	4.4	3.7	1	4.5	3.7	·
Precipmm	·	·	·	·	·	·	·	·	·	·	0.8	0.4	·	0.1	0.1	0.1	0.1	·	·	1.0	1.1	8.3	5.2	3.8	1.0	4.5	3.7	·
Windkm/h	1	2	1	2	6	1	1	4	2	1	4	3	3	9	4	3	8	5	11	14	9	6	7	5	4	10	8	8
Mid-mountain3,306 mModeled
Temp°C	-2°	8°	-2°	1°	10°	1°	2°	10°	1°	3°	8°	2°	2°	8°	2°	2°	9°	2°	3°	8°	2°	2°	-1°	-2°	-1°	-1°	-3°	-3°
Feels like°C	-5°	5°	-7°	-2°	6°	-5°	-1°	5°	-4°	-1°	3°	-4°	-1°	4°	-4°	-1°	6°	-4°	0°	3°	-2°	-0°	-5°	-5°	-4°	-5°	-6°	-6°
Snowcm	·	·	·	·	·	·	·	·	·	·	·	·	·	·	·	·	·	·	·	·	0.1	2.6	3.1	2.7	0.7	3.4	2.8	·
Precipmm	·	·	·	·	·	·	·	·	·	·	0.7	0.4	·	0.1	0.1	·	0.1	·	·	0.6	0.8	7.5	4.4	3.2	0.9	3.9	3.2	·
Windkm/h	1	2	1	2	6	1	1	4	2	1	4	3	3	9	4	3	8	5	11	14	9	6	7	5	4	10	8	8
Base2,830 mModeled
Temp°C	0°	11°	1°	3°	14°	3°	4°	13°	4°	5°	12°	4°	5°	12°	5°	5°	12°	5°	6°	12°	5°	5°	2°	2°	3°	2°	0°	0°
Feels like°C	-2°	8°	-4°	1°	9°	-1°	2°	8°	-1°	3°	7°	-1°	3°	8°	0°	3°	9°	0°	4°	7°	2°	3°	-2°	-2°	-0°	-2°	-2°	-2°
Snowcm	·	·	·	·	·	·	·	·	·	·	·	·	·	·	·	·	·	·	·	·	·	2	1.9	1.7	0.5	2.4	2.2	·
Precipmm	·	·	·	·	·	·	·	·	·	·	0.7	0.4	·	0.1	0.1	·	0.1	·	·	0.6	0.8	7.4	4.2	3.0	0.9	3.9	3.2	·
Windkm/h	1	2	1	2	6	1	1	4	2	1	4	3	3	9	4	3	8	5	11	14	9	6	7	5	4	10	8	8
Humidity%	37	18	57	31	19	40	38	23	62	73	68	89	79	38	80	65	33	78	84	81	96	69	70	35	35	51	56	53
0°C linem	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	3,400	2,950	2,400	2,300	2,650	2,950	2,450
Sunhours																						9	6.5	9.4	9.2	9.1	9	9

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 Keystone, side by side for 14 days

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

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SnowSure™ blend — verified model weighting

The black line is not a simple average. For Keystone (rockies), 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

Rockies & Southwest region

14 Day map is in SnowSure ProUnlock with Pro

El Niño Outlook · Winter 2026-27

Keystone El Niño rank & forecast

Keystone ranks #208 of 488 SnowSure resorts — Tier C, 0% in strong El Niño winters.

Tier C — ENSO-proof: Strong El Niño winters looked like a normal year here — within about ±3% of this resort’s own 30-year snowfall average. Not a jackpot, not a bust: a hedge if you’re planning around El Niño.

#208 of 488Tier C — ENSO-proof

Strong-event signal: 0% vs this resort's 30-yr avg

In the three strongest El Niño winters on record ('97-98, '15-16, '23-24), Keystone averaged +0% versus its own 30-year snowfall baseline — effectively ENSO-proof. Keystone has held within a few percent of normal across every phase of the Pacific cycle, making it one of the safest bets of a record El Niño winter 2026-27. Analog winters: '97-98 -17%, '15-16 +2%, '23-24 +16%.

'97-98 −17%'15-16 +2%'23-24 +16%

Signal = average snowfall in the three strongest El Niño winters since 1996 ('97-98, '15-16, '23-24) vs this resort's own 30-year ERA5 baseline. n=3 — a lean, not a law. Updated monthly against measured snowfall Dec–Mar.

Full El Niño report →

Key

What the tiers mean

% vs each resort's own 30-year average in strong El Niño winters.

Tier	Signal	Means
A — Prime terrain	≥ +8%	Historically much snowier than normal.
B — Favored	+3% to +8%	Modest upside vs normal.
C — ENSO-proof	about −3% to +3%	Near-normal snowfall — a hedge, not a jackpot or bust.
D — Late bloomer	−3% to −8%	Often lighter early — aim Feb–Mar.
E — Timing play	≤ −8%	Often lighter overall — aim late winter.

ENSO seasonal analog

History · not a forecast

In 10 past El Niño winters at Keystone, ERA5 season snowfall median was 305 cm (120 in), about 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

305cm

10 El Niño winters · ≈ long-term median

All-season median

305cm

Across 30 ERA5 seasons (2026-27)

Phase	Seasons	Median	p25–p75	Recent analogs
El Niñocurrent	10	305cm	298cm – 333cm	2023, 2019, 2018, 2015, 2014, 2009
La Niña	12	306cm	264cm – 318cm	2022, 2021, 2020, 2017, 2011, 2010
ENSO-neutral	8	293cm	265cm – 331cm	2025, 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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