Naturally with it being winter and high altitude, it can get cold. Certain months are typically colder than others, such as December and January being the coldest. But each resort varies in how cold it gets depending on many factors such as:
If the resort is south-facing vs. north-facing
If the resort is in a valley as opposed to being located nearer the peak of the mountain
If the resort is more exposed to wind or not.
But if you're concerned about the cold or unsure if your gear is good enough, then there's no harm in looking at going later in the season, such as March or April, when temperatures are usually warmer (but be aware, weather is unpredictable, so you may sometimes be blessed by a cold dump of snow randomly at various points on your trip!)