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The Montbell Thermawrap Guide is an almost-waterproof synthetic insulated parka that scores near the middle of the pack in our ratings. The jacket weighs 18.7 oz. (530 g) and is warm enough for overnight trips in warmer, wetter winter conditions where its waterproof fabric is beneficial. The seams are not taped and, therefore, it is not completely waterproof.

Waterproof insulated jackets are very specialized. If they’re highly durable, they are excellent for long-term use around town and activities like downhill resort skiing. However, we rarely recommend them for activities where saving weight is a priority (e.g. backpacking, climbing, mountaineering, etc.) because, most of the time, a separate rain jacket and insulated jacket with a higher warmth to weight ratio perform better and are a better value. We have found that lightweight highly water resistant and waterproof insulated jackets are best for use as a climbing belay parka. But, even then, there must be a lot of dripping water or heavy, wet snow to warrant the water resistance.

Features & Specifications

  • Lightweight waterproof fabric (though the seams are not taped)
  • 18.7 oz. (530 g) in men’s medium
  • Designed for alpinism
  • Exceloft short-staple synthetic insulation:
    • 3.5 osy (120 gsm) in the torso
    • 2.4 osy (80 gsm) in the sleeves
    • 1.5 osy (50 gsm) in the hood

Description of Field Testing

We tested this jacket on several winter hiking and skiing day trips in the mountains near Anchorage, Alaska. The author’s most instructive test was a multi-day “Darkest Days Traverse,” a lightweight solo mountaineering ridge traverse during the shortest days of the year–only five hours of daylight. Dark, cold, windy, snowy, sleeping in a bivy sack while wearing the jacket.

Performance Assessment

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