Know your Boston snow day chances before the school announcement. Enter your ZIP code and get a weather-based closure prediction in seconds.
Our Snow Day Calculator analyzes current forecast data for Boston, MA — nor'easter snowfall, coastal ice risk, temperature swings, and more — and gives you an instant school closure estimate based on Suffolk County and Greater Boston closure patterns.
Boston winters are defined not by lake-effect bands but by powerful coastal storms — nor’easters — that can bury the city under 12–24 inches of snow in under 24 hours. Averaging around 48 inches of snowfall annually, Boston experiences some of the most dramatic winter weather variability on the East Coast: a nor’easter can arrive as heavy wet snow, shift to sleet, then turn to rain, all in the same storm.
Our Snow Day Calculator is tuned for Boston’s coastal climate: the rapid snow-to-rain transitions that change closure decisions at the last minute, the coastal ice risk from Atlantic storms, and the closure patterns across the dozens of independent school districts in Greater Boston.
Nor’easters form when cold Arctic air from Canada collides with warm, moist air from the Atlantic Ocean along the East Coast. The storm system rotates counterclockwise, pulling northeast winds — hence the name — and driving moisture inland over Boston. A well-positioned nor’easter can drop 12–24 inches on the city in 18–24 hours, with wind gusts topping 50–60 mph along the coast.
Boston’s coastal position makes precipitation type one of the most critical — and hardest to forecast — factors in any winter storm. A nor’easter tracking just 50 miles offshore can deliver 18 inches to Worcester while Boston gets 6 inches of wet snow that quickly transitions to rain. This variability makes Boston snow day decisions more uncertain than in inland cities, and it’s why our calculator shows a probability range rather than a hard prediction.
Boston’s freeze-thaw cycle — temperatures near 32°F that flip between freezing and above-freezing multiple times per winter — creates persistent black ice hazards on sidewalks, bus stops, and roads. Even after snowfall has ended, a nighttime re-freeze can make a morning commute more dangerous than the storm itself. Our calculator factors overnight temperature forecasts into ice risk scoring.
Boston proper is a dense urban city where students often walk or take the MBTA — meaning BPS decisions weigh sidewalk conditions and transit reliability heavily. Suburban districts like Newton, Brookline, and Quincy rely almost entirely on buses across longer routes with more exposure to blowing snow and drifting. Our calculator uses your specific ZIP code to reflect the conditions at your location, not a metro-wide average.
Greater Boston has dozens of independent school districts across Suffolk, Norfolk, and Middlesex counties. Here’s how the major districts approach snow day decisions.
BPS is the largest district in Massachusetts and the most closely watched in the region. Because many Boston students walk to school or use the MBTA, BPS places heavy weight on sidewalk conditions and transit service alongside snowfall totals. The superintendent coordinates with the mayor’s office and city emergency management. Closure announcements typically arrive by 6:00 AM, often earlier during major nor’easters.
Typical closure trigger: 4"+ overnight with ongoing accumulation, icy sidewalks, or major MBTA service disruptions.
Newton is a western suburban district with extensive bus networks across hilly terrain — conditions that make it more sensitive to icy roads than flat urban areas. Newton often coordinates closure decisions with neighboring districts (Brookline, Wellesley, Needham) and tends to close slightly earlier than BPS when a nor’easter is forecast to arrive during the morning commute window.
Typical closure trigger: 5"+ overnight with ongoing snow, or icy road conditions on hilly Newton bus routes before 5:30 AM.
Cambridge sits directly adjacent to Boston and faces similar urban conditions — students walking and using public transit, dense neighborhoods where plows reach quickly. Cambridge typically mirrors BPS closure decisions, though the district occasionally stays open when BPS closes if local conditions are slightly better. The Harvard/MIT presence means the city invests heavily in rapid snow clearing.
Typical closure trigger: Aligned with BPS — 4–5"+ with icy or ongoing conditions during the morning window.
Quincy is a coastal city south of Boston, directly exposed to nor’easter winds and coastal flooding risk. The district’s coastal position means it can see heavier snow and more intense wind than downtown Boston during offshore storm tracks, and Quincy is one of the more conservative Greater Boston districts when coastal storm warnings are active.
Typical closure trigger: 5"+ or coastal storm warnings with forecast wind gusts above 35 mph during school hours.
The National Weather Service Boston office (weather.gov/box) issues winter storm watches, warnings, and advisories for Suffolk County and the Greater Boston metro. When a nor’easter warning is active — especially with forecast totals above 8 inches — Boston-area districts enter closure alert mode. Sign up for NWS Boston text alerts at weather.gov and follow @NWSBoston on social media for real-time band updates.
Boston local stations WBZ (CBS) and WCVB (ABC) run continuous school closing scrolls during active storm events. Most Greater Boston districts post closures to school-data.com and their district websites by 6:00 AM. During major nor’easters, many suburban districts — Newton, Brookline, Wellesley — announce the evening before once the NWS issues a winter storm warning for the area.
For Boston, the difference between a major snowstorm and a rain event is often just the storm track. A nor’easter tracking 100 miles offshore keeps Boston in heavy snow; one tracking closer to shore can flip the city to rain while western suburbs get 18 inches. Check the NWS forecast discussion at weather.gov/box the night before a storm — it explains the track uncertainty and what each scenario means for snowfall totals.