Arc’teryx Atom SL vs LT

Arc’teryx Atom SL vs LT

Arc’teryx Atom SL vs LT: An In-Depth Comparison

As an avid adventurer passionate about veganism and sustainable choices, I know how crucial it is to have the right gear for every outdoor escapade. The Arc’teryx Atom series has been a favorite among outdoor enthusiasts, and today, we’re diving deep into a comparison of the Atom SL and Atom LT. Both jackets offer unique features tailored to different needs, but which one should you choose? Let’s find out.

Key Features and Technologies


Atom SL (Super Light)

  • Insulation: Coreloft Compact 40 g/m²
  • Temperature Range: Best for mild conditions, late spring to early fall
  • Weight: Approximately 8.6 oz (244 grams) for men’s medium

The Atom SL is designed to provide light insulation for high-exertion activities in milder climates. This makes it perfect for activities like spring hiking, summer alpine climbing, or as a lightweight travel companion. The lower amount of Coreloft insulation keeps the jacket lightweight and highly packable, ensuring it doesn’t weigh you down during intense activities.

Atom LT (Lightweight)

  • Insulation: Coreloft Compact 60 g/m²
  • Temperature Range: Suitable for colder conditions, winter layering
  • Weight: Approximately 13.2 oz (375 grams) for men’s medium

The Atom LT, on the other hand, offers more insulation, making it better suited for colder weather. This jacket is an excellent choice for winter hikes, mountaineering, or as an insulating layer under a shell in frigid conditions. The increased insulation provides extra warmth without adding significant bulk, making it a versatile option for various cold-weather activities.

Fabric Technologies

Both jackets incorporate Arc’teryx’s innovative fabric technologies:

  • Tyono 20 Denier Shell: This fabric is both lightweight and durable, providing a good balance between weight and protection.
  • Hardface Technology: Enhances the abrasion resistance of the fabric, making the jackets more durable and long-lasting.
  • Bluesign Approved Materials: Reflects Arc’teryx’s commitment to environmentally friendly and sustainable production practices.
  • Permeair Liner: Increases breathability, ensuring comfort during high-exertion activities by allowing moisture to escape.

The Atom LT’s shell is slightly more robust compared to the Atom SL, which provides better weather resistance. This makes the LT more suitable for harsher conditions, while the SL’s lighter fabric enhances mobility and is perfect for more dynamic activities.

Weather Protection

Atom SL

  • Weather Resistance: The Atom SL is water-resistant with a durable water repellent (DWR) finish, making it suitable for light rain and damp conditions. However, it is not fully waterproof.
  • Wind Resistance: Offers moderate wind resistance, suitable for light winds and mild conditions.

Atom LT

  • Weather Resistance: The Atom LT offers improved water resistance thanks to a thicker shell and DWR finish. It provides better protection against heavier rain and wet conditions.
  • Wind Resistance: With higher wind resistance, the Atom LT is suitable for stronger winds and colder conditions.

The Atom LT’s additional insulation and more substantial shell make it more effective in handling harsh weather. In contrast, the Atom SL excels in lighter, milder conditions where high mobility and breathability are prioritized.

Comfort and Fit

Both jackets offer a trim, athletic fit that allows for layering without bulkiness. Key features contributing to comfort and fit include:

  • Fleece Side Panels: These panels improve mobility and breathability, ensuring you stay comfortable during high-exertion activities.
  • Adjustable Hem and Hood: These features enhance fit and provide added protection against the elements, ensuring a snug fit that keeps out wind and rain.

The Atom SL feels almost weightless, making it ideal for activities that require high mobility, such as climbing or running. The Atom LT, while slightly heavier, offers more warmth without significantly compromising on movement, making it suitable for a broader range of conditions and activities.

Performance in Various Conditions

Cold Weather

Atom LT

  • Superior Warmth: The Atom LT is designed for superior warmth, making it suitable for winter hikes, mountaineering, and other cold-weather activities. Its higher insulation (Coreloft Compact 60 g/m²) and robust shell provide excellent thermal protection, ensuring you stay warm even in freezing conditions.

Atom SL

  • Cool Summer Nights: The Atom SL performs well in milder conditions, such as cool summer nights or as a light insulating layer during high-exertion activities. Its lighter insulation (Coreloft Compact 40 g/m²) is ideal for keeping you warm without overheating during moderate temperatures.

Wet Conditions

Atom LT

  • Better Rain Repellence: The Atom LT offers better rain protection due to its thicker insulation and more robust shell with a durable water repellent (DWR) finish. This makes it more effective at repelling rain and wet conditions, keeping you dry longer compared to the SL.

Atom SL

  • Light Rain Protection: The Atom SL is adequate for light rain and damp conditions. However, its lighter shell and lower insulation make it less suitable for heavy downpours. It can handle short, mild showers but is not designed for prolonged exposure to heavy rain.

High-Exertion Activities

Atom SL

  • Optimized for Breathability: The Atom SL excels in high-exertion activities where breathability and lightweight performance are crucial. Its design prioritizes ventilation and mobility, making it ideal for activities like running, climbing, and intense hiking.

Atom LT

  • Warmth Without Overheating: While the Atom LT provides significant warmth, it is also designed to manage body heat during high-exertion activities. Its fleece side panels and breathable construction help regulate temperature, preventing excessive overheating while maintaining warmth.

Weight and Packability

Atom SL

  • Weight: 8.6 oz
  • Packability: The Atom SL is highly compressible, fitting easily into small spaces like backpacks or travel bags. Its lightweight design makes it perfect for minimalist packing and high-mobility activities.

Atom LT

  • Weight: 13.2 oz
  • Packability: While still compressible, the Atom LT is slightly bulkier due to its additional insulation. It remains portable and packable but requires a bit more space compared to the SL.

Versatility and Use Cases

Atom SL

  • Ideal for: Spring, summer, and early fall activities, high-exertion sports, and travel. Its lightweight and breathable design make it versatile for various moderate conditions.
  • Not Ideal for: Extremely cold or wet conditions. The lighter insulation and less robust weather protection limit its use in harsh environments.

Atom LT

  • Ideal for: Winter activities, colder climates, and as a mid-layer in extreme cold. Its superior insulation and weather resistance make it suitable for a wide range of cold-weather applications.
  • Not Ideal for: Very warm weather or ultra-light packing needs. The heavier insulation can be too warm for hot conditions and adds some bulk compared to lighter alternatives.

Comparison Chart

FeatureAtom SLAtom LT
InsulationCoreloft Compact 40 g/m²Coreloft Compact 60 g/m²
Weight8.6 oz13.2 oz
Weather ResistanceModerateHigh
Ideal ConditionsMild, high-exertion activitiesCold, versatile use
MobilityVery HighHigh

This comprehensive analysis ensures that you have all the information needed to make an informed decision between the Arc’teryx Atom SL and Atom LT jackets based on your specific outdoor needs and conditions.


Choosing between the Arc’teryx Atom SL and LT depends largely on your specific needs. If you’re looking for a lightweight, highly breathable jacket for mild conditions and high-exertion activities, the Atom SL is your best bet. However, if you need a versatile, warm jacket that can handle colder weather and provide robust protection, the Atom LT stands out as the superior choice.

Both jackets reflect Arc’teryx’s commitment to quality and performance, ensuring you’re well-equipped for your next adventure. Whether you’re hiking through the mountains or navigating urban landscapes, these jackets offer the perfect blend of comfort, style, and functionality


  • Kyle Moore

    Kyle founded Kalook to merge his professional life with his love for the outdoors. When not working, Kyle enjoys hiking through nature, biking, camping, relaxing at the beach, exploring snowy terrains and forest walking.

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