Snow Day Predictor for Longmont, CO

Longmont is a mid-size city of about 92,088 people that sits across the northern mid-latitudes, near 40.2°N in Colorado. A winter here typically brings highly elevation-dependent, from a few inches in the valleys to feet in the high country. Elevation is everything — totals swing wildly across short distances. Because the town falls in the Mountain West climate region, our model's closure threshold for Longmont is held to a moderately high bar, reflecting districts that handle snow as a matter of course.

The percentage at the top of this page isn't a static guess — it's rebuilt each night from Longmont's own Open-Meteo forecast. The model reads seven signals from the overnight-into-morning window: total snowfall, whether any of it is timed for the 2–6 a.m. commute, freezing rain or sleet, the coldest air temperature, the wind chill, the peak wind, and how much snow is already on the ground. Valley districts handle routine snow well; closures hinge on heavy mountain storms, ice, or bitter cold. Late starts buy time for canyon roads and bus routes to be cleared.

Because a 2-hour delay clears a lower bar than an outright cancellation, you'll often see delay odds for Longmont even when the closure odds stay modest — that gap is the model flagging a borderline morning. The estimate shifts as the forecast firms up overnight, so it's worth re-checking Longmont's odds the evening before school. Treat it as a well-informed second opinion for planning, never as an official Colorado closing announcement.