You have learned to act fast and strike faster. The freezing winds of the high peaks are the force behind your blows, and the sapping cold is your ally.

Snowpeak Soul

Starting at 3rd level when you choose this subclass, you become acclimated to the freezing mountains. You have resistance to cold damage and you ignore the effects of extreme cold as described in the Dungeon Master's Guide. 

Guiding Wind

Starting at 3rd level, the winds assist you. As a bonus action on your turn, you may spend a ki point to cast the Zephyr Strike spell. Additionally, you learn the gust cantrip if you don't already know it. Wisdom is your spellcasting ability for these spells. 

Frigid Barrage

Starting at 6th level, the chill of the storm permeates your body. Whenever you use your Flurry of Blows or Stunning Strike feature, one target takes additional cold damage equal to your wisdom modifier. 

Hail Strike

At 11th level, you can project your freezing ki into blades of frost. Whenever you take the attack action on your turn, you may spend 3 ki points to replace one of the attacks with a casting of the ice knife spell at 1st level. Wisdom is your spellcasting ability for this spell. 

Storm's Fury

At 17th level, you can manifest a raging storm at the point of your blade. As an action on your turn, you may spend 4 ki points to cast the Steel Wind Strike. Wisdom is your spellcasting modifier for this spell.