The outdoors clothing-to-kit retailer reported a 12% rise in total sales to £84.7m during the 13 weeks to 6 January - aided by new store openings and a leap of almost 25% in online sales during the period.
The company, which currently trades from 340 stores employing more than 3,000 staff, said its planned expansion to 400 sites over the next 18 months was on track despite the tough economic backdrop.
That has seen a string of chains either seeking rescue deals or going to the wall as the high street battles consumer caution in the run-up to Brexit and a string of rising costs from things like business rates and minimum wage rules.
Mountain Warehouse, founded by the entrepreneur Mark Neale in 1997, has been a consistent performer over the years - growing from a single store in Swindon.
It argues that its success is a result of its business model: selling own-brand goods to cut out the "middleman".
Over the Christmas season it said it flogged over 500,000 pairs of socks, almost a million fleeces, over 500,000 winter jackets and over 400,000 pairs of gloves to more than three million customers globally.
Last year Mr Neale, the majority shareholder, sold a 20% stake to a private equity fund to pay for the company's continued store and online expansion.
Its overseas store estate is nearing 100 in eight other countries including New Zealand, Germany and Canada.
Mr Neale said of the latest trading update: "The business is continuing to perform strongly despite the economic backdrop.
"We had a bumper Black Friday weekend with total sales up 20% and online sales of over £1m for the first time in a single day.
"The prior year's performance was exceptional due to the cold weather and widespread snow we saw in the run up to Christmas 2017.
"I'm therefore really pleased to report this year's strong performance despite the unusually mild weather we have been experiencing.