Why is snow so hard to predict? Blame the Butterfly 🦋

❄️ Why it matters for skiers and snowboarders

Forecasts within 2–3 days are usually solid—high confidence. But once you’re looking 4 to 7 (or even 10) days out, it becomes more of an outlook—less precise, more about spotting trends.

Still, those longer-range outlooks have value. They help you get a feel for what’s coming: a potential storm, a warming trend, or that elusive powder window. It’s not about locking in exact inches—it's about timing your turns wisely.

Want to geek out on the science behind it? Here’s more on weather models and the butterfly effect from Michael Fagin, our operational meteorologist.

Accuracy of Extended Outlooks

We have had questions on the accuracy of extended outlooks. In these outlooks, we are looking at conditions 5 to 7 days out. The table below reflects the general accuracy of forecasts/outlooks. Notice that the overall confidence in a 1 to 3-day forecast is high, a 4 to 5-day forecast is moderate, and a 6 to 7-day forecast is lower confidence.

Why does the accuracy drop off over time? Weather forecasts are derived from numerical forecast models. Simply put, weather is not random but is a chaotic system. Thus, small changes early can lead to big differences later; this is called the "butterfly effect". That is why accuracy drops over time. This is a rather complicated topic. For more details on the chaotic system and butterfly effect, click on the links provided.

In conclusion, I think there is value in my 5 to 7-day outlooks, since I look at many different models to see a general trend. When I issue a 5 to 7 day weather discussion, I call it an outlook, not a forecast. This captures the general patterns, which will usually give us the right trend, but not necessarily the exact details.

Whether you're a seasoned Powder Poobah reader or just found us while chasing snow, we’re glad you’re here. Our goal? Help you make the most of your ski days with honest, readable forecasts—no hype, no fluff.

If you're not already getting our twice-weekly Powder Alerts, you can subscribe here and stay a step ahead of the storm (or the slop). See you on the slopes!