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Tier C — ENSO-proof

North America

Projected to open November 14, 2026

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

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Projected to open Nov 14 — closed June 7

Weather data is still collected for informational purposes.

Last Snowfall

Oct 13

3d ago

Past 24 Hours

0cm

Past 48 Hours

0cm

Past 10 Days

1cm

7-Day Forecast

31cm

Snow Depth

Updated: Oct 16, 12:00 PM•Weather at base: 2,424m

SnowSure™ Score2025-26 season

Projected to open Nov 14

Mammoth Mountain is projected to open November 14, 2026. Here is when it is usually best to book.

Best months to book

#1February88cm avg
#2January87cm avg
#3March73cm avg · last season 14.3

Best weeks to book

#1 20 Mar – 25 Mar · last season 14
#2 27 Mar – 2 Apr · last season 18.4
#3 10 Apr – 16 Apr · last season 34.4

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

Snow qualityHeavyAverageLightmeasuredestimated

Freezing line

1cm

Season

1cm

Past 10 days

0cm

48h

0cm

24h

0cm

Today

40cm

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

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Thu22

Fri23

Sat24

Sun25

Mon26

Tue27

Wed28

Thu29

Freezing line

Snow qualityHeavyAverageLightmeasuredestimated

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

Hourly Forecast

	16 Fri 12° / -1°			17 Sat 11° / 1°			18 Sun 10° / -0°			19 Mon 6° / -3°			20 Tue -1° / -5°			21 Wed -1° / -10°			22 Thu -1° / -10°			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	clear	clear	clear	clear	clear	clear	cloudy	snow	snow	light snow	light snow	cloudy	mostly clear	snow	some clouds	mostly clear	clear	mostly clear	clear	cloudy	cloudy	clear
Summit3,369 mModeled
Temp°C	1°	9°	0°	3°	10°	1°	3°	10°	1°	1°	6°	-1°	-1°	1°	-3°	-3°	-2°	-4°	-4°	-2°	-6°	-3°	-3°	-3°	-2°	-1°	-0°	-2°
Feels like°C	-3°	7°	-4°	1°	6°	-1°	1°	4°	-2°	-3°	-1°	-6°	-7°	-6°	-8°	-9°	-6°	-10°	-7°	-5°	-11°	-6°	-3°	-1°	-1°	0°	-0°	-1°
Snowcm	·	·	0.1	·	·	·	·	·	·	·	·	·	0.2	1.8	2.5	2.5	11.6	14.5	0.4	1.6	4.3	7	2.8	0.7	2.9	·	·	2.3
Precipmm	·	·	0.2	·	·	·	·	·	·	·	·	·	0.1	2.4	2.8	3.5	17.4	19.2	0.3	2.3	5.1	8.1	3.1	0.4	3.4	·	·	3.2
Windkm/h	15	10	16	3	8	3	2	11	3	10	22	9	9	5	6	3	4	4	3	2	5	13	10	4	5	5	5	7
Mid-mountain2,897 mModeled
Temp°C	4°	12°	3°	5°	13°	3°	5°	13°	3°	4°	9°	2°	1°	5°	0°	-1°	2°	-2°	-1°	1°	-2°	-0°	-0°	-0°	0°	1°	2°	0°
Feels like°C	-2°	9°	-3°	-1°	9°	-2°	-1°	11°	-3°	-3°	3°	-4°	-4°	-2°	-5°	-7°	-2°	-7°	-5°	-1°	-8°	-3°	-1°	0°	1°	1°	2°	1°
Snowcm	·	·	0.1	·	·	·	·	·	·	·	·	·	0.1	0.7	1.7	1.6	6.8	10.2	0.3	1.1	3	4.5	1.9	0.7	2.1	·	·	1.8
Precipmm	·	·	0.1	·	·	·	·	·	·	·	·	·	·	1.2	2.1	2.7	14.2	14.5	0.4	2.5	4.4	6.6	2.5	0.3	2.8	·	·	2.6
Windkm/h	5	8	4	1	8	3	3	5	5	12	23	10	10	8	6	2	4	3	3	5	4	10	3	4	5	4	4	5
Base2,424 mModeled
Temp°C	6°	16°	6°	7°	17°	6°	8°	17°	6°	6°	12°	4°	4°	8°	3°	2°	5°	2°	2°	5°	1°	3°	3°	3°	4°	4°	5°	3°
Feels like°C	2°	12°	1°	3°	13°	2°	2°	14°	1°	1°	6°	-1°	-1°	1°	-2°	-3°	1°	-4°	-1°	3°	-4°	0°	2°	3°	4°	4°	5°	5°
Snowcm	·	·	·	·	·	·	·	·	·	·	·	·	0.1	0.4	1	0.6	1.7	3.3	0.1	0.2	1.7	1.6	1.1	0.3	0.4	·	·	1.2
Precipmm	·	·	0.1	·	·	·	·	·	·	·	·	·	·	0.8	1.4	1.8	9.3	9.5	0.3	1.8	2.9	4.3	1.6	0.2	1.8	·	·	1.6
Windkm/h	5	8	4	1	8	3	3	5	5	12	23	10	10	8	6	2	4	3	3	5	4	10	3	4	5	4	4	5
Humidity%	48	20	60	47	18	50	59	16	61	48	25	57	47	59	77	82	61	88	70	51	85	59	34	36	35	39	40	44
0°C linem	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	2,950	2,800	3,150	3,650	4,050	2,850	2,450
Sunhours																						6	6	6	6	6	6	6

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 Mammoth Mountain, 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 Mammoth Mountain (sierra), 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

California & Sierra Nevada region

14 Day map is in SnowSure ProUnlock with Pro

El Niño Outlook · Winter 2026-27

Mammoth Mountain El Niño rank & forecast

Mammoth Mountain ranks #249 of 488 SnowSure resorts — Tier C, −3% 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.

#249 of 488Tier C — ENSO-proof

Strong-event signal: −3% vs this resort's 30-yr avg

In the three strongest El Niño winters on record ('97-98, '15-16, '23-24), Mammoth Mountain averaged -3% versus its own 30-year snowfall baseline — effectively ENSO-proof. Mammoth Mountain 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 -4%, '15-16 -32%, '23-24 +27%.

'97-98 −4%'15-16 −32%'23-24 +27%

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 Mammoth Mountain, ERA5 season snowfall median was 380 cm (150 in), about 6% above 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

380cm

10 El Niño winters · 6% above median

All-season median

360cm

Across 30 ERA5 seasons (2026-27)

Phase	Seasons	Median	p25–p75	Recent analogs
El Niñocurrent	10	380cm	284cm – 452cm	2023, 2019, 2018, 2015, 2014, 2009
La Niña	12	355cm	297cm – 524cm	2022, 2021, 2020, 2017, 2011, 2010
ENSO-neutral	8	306cm	227cm – 526cm	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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