Lucy Wallace explains why, even during a heatwave, she was glad to have the Montane Women’s Fireball jacket as a spare layer living at the bottom of her mountain bag.

The Montane Women’s Fireball Jacket comes into its own either as a midlayer in winter, or a spare emergency layer in summer conditions. The Clo Vivo insulation is not quite as compressible as some, due in part to its structure in perforated sheets; but it is really breathable and wicks exceptionally well, which is why it is featured in our guide to the best synthetic insulated jackets.

Price: $299 | £200 | Weight: 366g (size 12) | Materials: shell: Featherlite Air nylon stretch; fill: 55% recycled 60gsm Clo Vivo Extreme Eco | Features: Hood, zipped handwarmer and chest pockets, elasticated cuffs | Sizes: 8-16 | Men’s version: Yes

Perhaps because of its positioning as a ‘mid layer’, the hood is not adjustable, and is best worn under rather than over a helmet. Likewise, it lacks a two-way zip so a climber will need to tuck it into their harness. The cuffs and face opening in the hood are elasticated and there’s a brushed microfleece chinguard. 

Described as an “active fit” I found the sizing to be very generous nonetheless. The shell and insulation are quite stretchy too. It’s great for athletic activities as well as layering up for keeping warm around camp in the evenings. 

I tested the Montane Women’s Fireball Jacket over a long summer of wild camping with mixed weather conditions, initially quite cool. Even during the heatwave, I was glad to have it as a spare layer living at the bottom of my mountain bag. It’s had heavy use, and has stood up really well, with no sign of wear so far.