Badwater 135 Weather: Complete Guide to the Hottest Race on Earth

The Badwater 135 ultramarathon begins at the lowest point in North America—Badwater Basin, 282 feet below sea level—and climbs 135 miles across Death Valley to Mt. Whitney Portal, at 8,360 feet elevation. This course profile alone would make it a formidable challenge. But Badwater runs in mid-July, when Death Valley routinely records the hottest temperatures on Earth. Runners face air temperatures exceeding 120°F, pavement temperatures above 200°F, and the relentless brutality of desert heat that transforms mere movement into a survival challenge. The weather at Badwater isn't just a factor—it IS the race.

This guide covers everything about Badwater 135 weather: the extreme conditions runners face, the physiology of running in life-threatening heat, survival and pacing strategies, the preparation required to attempt this race, and what draws athletes to test themselves against the hottest weather on the planet.

Understanding Death Valley Heat

Why Death Valley Is the Hottest Place

The geography of extreme heat:

The geography:

Below sea level basin surrounded by high mountains
Hot air descends and is trapped
Mountains block any cooling oceanic influence
Sparse vegetation offers no cooling effect
Terrain absorbs and radiates heat

The physics of extreme heat:

Clear skies allow maximum solar radiation
Low humidity means no evaporative cooling in the environment
High thermal mass (rock, sand) stores and radiates heat
Air compression in below-sea-level basin adds warmth
Everything combines to create the hottest place on Earth

The records:

Highest reliably recorded air temperature: 134°F (1913)
Regularly exceeds 120°F in July
Ground temperature can exceed 200°F
Overnight lows may stay above 100°F
This is heat beyond normal human experience

Badwater Weather During the Race

What runners actually experience:

Typical race conditions:

Start temperature (6:00 PM): 105-115°F
Overnight low: 90-105°F (yes, the LOW)
Midday high (next day): 120-130°F
Ground temperature: 180-200°F+
Direct sun radiation is intense

The timing logic:

Race starts at 6:00 PM, not morning
Cooler (relatively) evening start
Night miles in "only" 100-110°F
Hottest midday hours on subsequent day(s)
Still brutal but marginally better than morning start

The progression:

First night: Hot but manageable with support
Dawn brings temperature rise
Midday of Day 2: Peak brutality
Second night (if still out): Heat stress accumulation
Conditions don't meaningfully relent until Mt. Whitney climb

The Pavement Problem

Why the ground is more dangerous than the air:

Ground temperature reality:

Black pavement absorbs all solar radiation
Can reach 200°F or higher
Heat radiates upward constantly
Standing on the road feels like standing on a griddle
Your feet are cooking from below

The white line strategy:

White road line is slightly cooler than black pavement
Many runners stay on the white line when possible
Temperature difference can be 10-20°F
Small advantage but meaningful over 135 miles
Every degree matters

Footwear implications:

Standard running shoes may not provide enough insulation
Some runners use thicker-soled shoes
Gaiters prevent sand/debris but add heat
Blisters are almost universal
Feet are a major limiting factor

The Physiology of Extreme Heat Running

How Your Body Responds

The failing cooling system:

Normal heat response:

Blood flow increases to skin
Sweat production increases
Evaporation cools the body
Core temperature stabilizes
System works up to a point

When the system breaks down:

At 120°F+, air is hotter than skin
Convective cooling reverses (air heats you)
Sweat evaporates but may not cool enough
Blood flow to skin compromises muscle blood supply
Core temperature rises despite all efforts

The dangerous cascade:

Core temperature rises above 104°F
Cognitive function begins to decline
Sweating may decrease (bad sign)
Heart works extremely hard
Heat stroke becomes imminent

Survival through intervention:

External cooling becomes essential
Water, ice, shade
Cannot rely on body's systems alone
Active cooling required to survive
This is why crews are mandatory

The Energy Cost of Heat

What 120°F does to performance:

Metabolic realities:

Enormous caloric expenditure just to thermoregulate
Running compounds the heat production
Energy that could go to running goes to survival
Pace must be dramatically slower
This is physiology, not weakness

Heart rate consequences:

Heart rate skyrockets in extreme heat
Same pace requires much higher HR
Maximum HR may be reached at modest pace
Cardiac output is challenged
The heart is the limiting factor

Fluid and electrolyte demands:

Sweat rates can exceed 2 liters per hour
Electrolyte loss is massive
Dehydration happens despite drinking
GI system may struggle to absorb fluids
Hydration becomes a constant battle

Badwater Survival Strategies

Crew-Based Cooling

The support system that makes survival possible:

Why crews are mandatory:

Runners cannot carry enough water
External cooling is essential
Medical monitoring required
Logistical support needed
No crew = no race (and potentially no survival)

Crew cooling techniques:

Spraying water on runner constantly
Ice vests, ice bandanas
Cold water immersion (at stops)
Shade structures at crew vehicles
Fans when stopped

The spray strategy:

Crew vehicle follows runner
Constant water spraying on body
Evaporation provides cooling
Must maintain continuously
Stopping spray = temperature rises

Ice strategy:

Ice in hats, around neck
Carrying ice in hands
Ice baths at crew stops
Ice inserted in clothing
Every cooling method helps

Night Running Strategy

Using darkness for advantage:

The night benefit:

No direct sun radiation
Air cools (somewhat)
Ground starts to cool
Best hours for progress
Most competitive runners push hard at night

Night challenges:

Still extremely hot (100-110°F common)
Accumulated fatigue from hours of heat
Navigation in darkness
Crew fatigue affects support
Must balance pushing with preservation

Strategic night approach:

Make maximum progress during night hours
Bank miles for the brutal midday
Some runners minimize sleep to maximize night miles
Others take short naps and continue through day
Strategy depends on pace and goals

Pacing for Survival

How pace works at Badwater:

Forget normal pace:

Your marathon pace is meaningless here
Your ultra pace is meaningless here
Conditions determine pace
Some sections may be walking only
Finishing is the accomplishment

Section-based pacing:

First section (night): Can push somewhat
Furnace Creek to Stovepipe Wells: Hot but manageable
Stovepipe Wells to Panamint: Peak brutality (often midday)
Father Crowley to Lone Pine: Climbing, different challenge
Mt. Whitney Portal climb: Cooler, but cumulative fatigue

The midday survival mode:

10 AM to 4 PM: Survival pace
Walking may be necessary
Shade and cooling stops more frequent
Progress is slow but continuous
Staying alive is the goal

Cut-off awareness:

Race has time cutoffs
Must balance pace with survival
Some runners miss cutoffs in survival mode
Strategic decisions about pushing vs. resting
The balance is individual

Preparation for Badwater Heat

Heat Acclimatization

The essential training component:

Why acclimatization is non-negotiable:

You cannot show up untrained for this heat
Body needs physiological adaptations
Takes weeks of consistent exposure
Adaptations fade without maintenance
Insufficient heat training = DNF or worse

Acclimatization timeline:

Begin serious heat training 4-6 weeks before race
Minimum 60-90 minutes of heat exposure daily
Continue until race day
Can't do a brief heat block and be ready
This is a sustained commitment

Acclimatization methods:

Training in heat (running, walking)
Sauna exposure post-exercise
Overdressing in cooler conditions
Heat chamber training (if available)
Any and all methods that create heat stress

What acclimatization provides:

Increased sweat rate and efficiency
Earlier sweating (starts sooner)
Expanded blood plasma volume
Lower core temperature at given effort
Better cardiovascular efficiency in heat
You can't succeed without these adaptations

Training for the Course

Preparing for 135 miles in extreme heat:

Physical preparation:

High-volume ultra training base
Long runs in heat
Back-to-back long efforts
Significant vertical (10,000+ feet in race)
Night running practice

Gear testing:

All equipment tested in heat
Shoes that can handle hot pavement
Clothing that maximizes cooling
Hydration systems that work in heat
Nothing untested on race day

Crew preparation:

Crew is as important as runner
They need training too
Protocols for cooling, feeding, supporting
Communication systems
Backup plans for everything

Mental Preparation

The psychological demands:

What you're facing mentally:

Hours of suffering with no relief
Knowing it will get worse before it gets better
The isolation of extreme heat (even with crew)
Fear of physical limits
The question: "Why am I doing this?"

Building mental readiness:

Training in miserable conditions
Practicing continuing when you want to stop
Developing mantras and coping strategies
Understanding your "why"
Accepting suffering as part of the experience

The Badwater mindset:

This is voluntary extreme suffering
You chose this
The heat is the point
Finishing means conquering the elements
Every finisher has earned it

The Badwater Experience

What It's Actually Like

From those who've done it:

The start:

Standing in Badwater Basin, below sea level
The heat hits you immediately
135 miles of road stretching ahead
The adventure begins

The first night:

Making miles while conditions are "only" terrible
Crew settling into rhythm
Body still fresh but heat is relentless
Finding a groove

The furnace hours:

Sun rises and everything changes
Temperature climbs past 120°F
Movement becomes pure survival
Time dilates
The brutality reveals itself

The climb:

Leaving the desert floor
Temperature drops (slightly) with elevation
Legs are destroyed but conditions improve
The end becomes visible
Hope returns

The finish:

Mt. Whitney Portal at 8,360 feet
Temperature in the 70s feels arctic
135 miles conquered
The heat is behind you
You're a Badwater finisher

The Community

Who attempts this and why:

The Badwater runners:

Experienced ultramarathoners
Heat training specialists
Adventure seekers
Those driven to test absolute limits
A small, dedicated community

Why they do it:

To see what they're made of
The ultimate heat challenge
A unique accomplishment
Testing the intersection of physical and mental
Because it exists

The crew bond:

Crews share the experience
48+ hours of supporting their runner
Intense, exhausting, rewarding
Bonds formed in extreme conditions
Everyone who finishes earns it

The Dangers

Heat Illness at Badwater

The real risks:

What happens:

Heat exhaustion is common
Heat stroke is a real possibility
Medical drops occur
The danger is genuine
This is not a safe event

Warning signs:

Cessation of sweating (bad sign)
Confusion, disorientation
Nausea and vomiting
Extremely rapid heart rate
Core temperature above 104°F

Response protocol:

Stop immediately
Aggressive cooling
Medical evaluation
Possible evacuation
Life over race, always

The safety net:

Medical support throughout
Crew monitoring constantly
Race officials checking runners
Hospitals accessible
But personal responsibility is primary

Is This Safe?

The honest assessment:

The risks:

Heat illness can be fatal
Cardiac events possible
Dehydration can cause organ damage
Long-term effects possible
This is genuinely dangerous

The mitigations:

Proper heat acclimatization
Experienced crew
Mandatory medical checks
Pull-out protocols
Smart decision-making

The reality:

Deaths have not occurred at Badwater (as of recent years)
Medical drops do occur
Proper preparation reduces risk
It's still extreme
Not for casual bucket-listers

Key Takeaways

Temperatures exceed 120°F. This is the hottest place on Earth, and you're running through it.
Pavement can reach 200°F. The ground is often hotter than the air; foot management is critical.
Crews are mandatory. You cannot survive this without constant external support and cooling.
Heat acclimatization is essential. Weeks of dedicated heat training are required before attempting.
Night hours are precious. Make maximum progress when temperatures "only" reach 100-110°F.
Normal pacing doesn't apply. Forget your usual ultra pace; conditions determine speed.
The danger is real. Heat illness can be fatal; this requires respect and preparation.
Finishing is the accomplishment. Time is secondary; conquering the heat is the achievement.

Badwater 135 represents the absolute extreme of heat running. Run Window can help you prepare for hot-weather running at home, but Badwater requires dedicated preparation, an experienced crew, and a willingness to test yourself against the planet's harshest conditions.