Arc'teryx Atom vs. Proton: Which one is better? [2026]

The Arc'teryx Atom and Proton jackets are both premium synthetic insulators, but they are built for entirely different purposes. The Atom is a versatile, all-around insulated jacket that prioritizes warmth and wind resistance, making it perfect as a standalone piece for everyday use or moderate activity. In contrast, the Proton is a highly breathable active insulation layer designed to regulate temperature during high-output activities like climbing and ski touring, prioritizing air permeability over wind resistance.

Here's a complete comparison to help you choose the right Arc'teryx jacket for your needs.

Arc'teryx Atom Hoody

The Arc'teryx Atom Hoody is arguably the brand's most recognizable and versatile piece of gear. It's a synthetically insulated jacket that strikes an exceptional balance between warmth, weather resistance, and everyday comfort. Designed as a do-it-all layer, it functions perfectly as a standalone jacket in cool, dry conditions or as a warm midlayer under a hardshell when the weather turns.

• What it is: A best-selling, synthetically insulated hoody that serves as a versatile warming layer for a wide range of activities and conditions.
• Key features: Coreloft™ Compact insulation that retains warmth when wet, a weather-resistant Tyono™ 20 face fabric, and highly breathable stretch fleece side panels for better movement and ventilation.
• Price: Around $300
• Materials/Construction: Durable Tyono™ 20 face fabric with a DWR (Durable Water Repellent) finish sheds light moisture, while Coreloft™ Compact 60 insulation is mapped for optimal thermal performance.
• Sizing/Fit: Regular fit that's slightly more relaxed than the Proton. It's designed to layer easily over a base layer and under a shell, with a comfortable hip-length cut.
• Pros: Highly versatile for city and mountain use, excellent warmth-to-weight ratio, effectively blocks wind, comfortable fleece side panels add breathability, very durable for its weight.
• Cons: Less breathable than the Proton during high-intensity exercise, the face fabric isn't as air-permeable which can lead to overheating, only water-resistant (not waterproof).

This jacket is ideal for individuals who need one reliable insulated layer for daily wear, hiking, resort skiing, and casual outdoor use.

Shop this product: arcteryx.com/us/en/shop/mens/atom-hoody

Arc'teryx Proton Hoody

The Arc'teryx Proton Hoody is purpose-built as an active insulation piece for demanding mountain pursuits. Its entire design is centered around one thing: breathability. It's engineered to work as a self-regulating midlayer that you can put on and leave on, preventing the cycle of overheating while moving and getting cold when you stop. This makes it a specialist tool for high-output activity.

• What it is: A breathable, synthetically insulated jacket designed as a performance midlayer for high-intensity activities in cold weather.
• Key features: Extremely air-permeable Fortius™ Air 20 face fabric, Coreloft™ Compact insulation for efficient thermal regulation, a helmet-compatible hood, and articulated elbows for climbing mobility.
• Price: Around $350
• Materials/Construction: The fabric package is the star here. Fortius™ Air 20 offers exceptional abrasion resistance and air circulation, while mapped Coreloft™ Compact insulation provides warmth without trapping air.
• Sizing/Fit: Trim, athletic fit designed for maximum mobility and minimal bulk. It layers perfectly under a harness or shell without restricting movement.
• Pros: Unbeatable breathability prevents overheating during climbs or ski tours, surprisingly durable face fabric withstands abrasion, fantastic freedom of movement, effectively manages moisture.
• Cons: Lacks significant wind resistance by design, does not feel as warm as the Atom when stationary, and the trim fit may be too snug for some as a casual jacket.

This jacket is the choice for climbers, backcountry skiers, and alpinists who require a midlayer that breathes well and moves with them through dynamic activities.

Shop this product: arcteryx.com/us/en/shop/mens/proton-hoody

Arc'teryx Atom vs. Proton Comparison

Breathability & Air Permeability

This is the most critical difference between the two jackets. The Proton Hoody is built around air permeability. Its Fortius™ Air 20 face fabric intentionally allows airflow, which lets excess heat and moisture escape during intense activity. This dynamic breathability prevents the sweaty, clammy feeling you often get when climbing a steep trail.

Conversely, the Atom Hoody's Tyono™ face fabric is more focused on blocking wind. While it has stretchy fleece panels under the arms for some ventilation, its main body fabric is far less air permeable than the Proton's. This makes the Atom feel warmer when you're standing still but can lead to overheating if your heart rate spikes.

Warmth & Weather Resistance

When you're stationary, the Atom generally feels warmer than the Proton. This is simply because it holds onto your body heat better by blocking out the wind. Both jackets use comparable amounts of Coreloft™ insulation, so their potential for warmth is similar, but the Proton willingly lets air pass through, which can feel cooling.

Both models feature a DWR finish, providing decent resistance against light snow and drizzle, but neither is waterproof. For heavy rain or wet snow, you'll need to layer a hardshell over either jacket.

Fit & Intended Use

The Atom features Arc'teryx's "Regular Fit" profile, which offers enough room for comfortable layering and a casual look that works well in the city. It’s the quintessential all-rounder - perfect for cold-weather walks, campsite evenings, and layering for resort skiing.

The Proton uses a "Trim Fit" designed for athletic movement. It sits closer to the body to improve moisture wicking and reduce bulk under a harness or outer shell. This specialized, active fit makes it the superior choice for high-output mountain sports where mobility and efficiency are critical.

Price & Value

Both jackets are a premium investment, with prices typically separated by about $50. The value proposition depends entirely on your needs. For the average user, the Atom offers better value because its versatility spans a wider range of scenarios. You get a single piece for everyday wear, travel, and moderate adventures.

The Proton delivers exceptional value for dedicated outdoor athletes. If you frequently engage in sports that cause you to overheat, its specialized breathable performance is a truly worthwhile feature that fundamentally improves comfort and efficiency in the mountains.

Both jackets excel in their intended roles, but your primary activities will make the choice clear.

Choose the Atom if:

• You need a single versatile jacket for daily wear, travel, and moderate hiking.
• You prioritize warmth while stationary and wind resistance over constant breathability.
• You'll use it mostly as a standalone jacket in cool, dry weather or for stop-start activities like resort skiing.
• Comfort and all-around functionality are more important than specialized active performance.

Choose the Proton if:

• You need a highly breathable layer for high-output activities like ski touring, ice climbing, or alpine running.
• You frequently find yourself taking layers on and off as you move.
• Performance fit, mobility under a shell, and temperature regulation are your top priorities.
• You see this piece as a dedicated midlayer within a technical layering system.

Frequently Asked Questions

What's the main difference between the Arc'teryx Atom and Proton?

The main difference is breathability and intended use. The Atom is an all-around insulator that blocks wind and prioritizes warmth, making it versatile for general use. The Proton is a specialized active insulator with a highly breathable face fabric that purges heat and moisture during intense activity.

Is the Arc'teryx Atom or Proton warmer?

The Atom feels warmer when you're not moving because its less breathable fabric is better at blocking wind. During high-output activity, the warmth level can feel similar, but the Proton excels at regulating temperature to keep you from getting too hot or too cold.

Which is better for everyday use?

The Arc'teryx Atom Hoody is significantly better for everyday use. Its more relaxed fit, superior wind resistance, and versatile nature make it the perfect jacket for commuting, walking around town, and casual outings.

Which one should I get for skiing?

For resort skiing, with frequent stops for chairlifts, the Atom is usually the better choice for its reliable warmth and wind protection. For physically demanding backcountry skiing or ski touring, the Proton's superior breathability is essential for managing heat and sweat on the uphill ascent.

Are the Atom and Proton waterproof?

No, neither jacket is waterproof. Both are treated with a DWR (Durable Water Repellent) finish that causes light rain and snow to bead off, but they will become saturated in sustained precipitation. A waterproof hardshell jacket is required for wet conditions.

How do the Atom and Proton jackets fit?

The Atom has a regular fit, which leaves room for light layering underneath. The Proton has an athletic trim fit that sits closer to the body to maximize mobility and moisture-wicking and minimize bulk under a shell or harness.

Can I use the Proton as a standalone jacket?

Yes, the Proton works well as a standalone jacket in cool, calm, and dry conditions. However, because it is not wind-resistant, you may feel cool in breezy conditions compared to an Atom.

Does Arc'teryx have a good warranty?

Yes, Arc'teryx offers a limited warranty that covers defects in materials and workmanship for the practical lifetime of the product.