Natural snow is the best kind of snow, but when it comes to preparing most ski resorts for the upcoming winter season, snowmaking plays a big role. Read on for our quick take on how snowmaking works.

Snow Guns

The function of a snow gun is to blow tiny water droplets into the air, let them freeze, and fall to the ground. There are two primary types of snow guns.

The first type of snow gun combines compressed air and water. The compressed air splits the water into tiny droplets, while also launching it high enough to allow for the droplets to freeze. 

The second type of snow gun combines a stream of water with an electric fan. Instead of compressed air, the electric fan blows the water into tiny droplets that freeze and fall to the ground.

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Copper Mountain Snowmaking | October 3, 2019

Snow Forecast: Copper Mountain

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Wet-Bulb Temperature

The best measure of snowmaking conditions is something called the wet-bulb temperature. This is the combination of the actual air temperature and the amount of moisture in the air. 

Normal Temperature + Humidity = Wet-Bulb Temperature

Snowmaking is most efficient when the wet-bulb temperature is well below freezing. However, snow can still be made when the temperature is near freezing as long as the air is very dry. 

Humidity (Key Ingredient)

Water droplets freeze more quickly when the air is dry, and this is due to an effect called evaporational cooling.

When the air is not saturated, some water droplets in the air evaporate from a liquid to a gas. This evaporative process requires heat, and this heat is taken from the surrounding air. Thus, the surrounding air loses heat and becomes cooler.

Think of when you step out of the shower with a few droplets of water on your skin, and you feel a slight chill as you enter a dry room. This is evaporational cooling.

Example

32°F Temperature + 25% humidity = 24°F Wet-Bulb Temperature

This is well below freezing and plenty cold enough for efficient snowmaking.

Wet-Bulb Temp Guide for Snowmaking

Optimal: 10-20°F

Favorable: 8-10°F & 20-25°F

Marginal: 2-7°F & 25-28°F

Unfavorable: <2°F & >28°F

Snowmaking Forecast in OpenSnow

1. Go to any ski resort location.
2. Scroll down to "Forecast Range".
3. Swipe the chip to "Snowmaking (Wet Bulb Temp)".
4. Tap "View Interactive Chart" in the app.
5. Adjust the model and timeframe.

Here are two examples for Arapahoe Basin from Monday, October 13, 2025:

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Sam Collentine