❄️ Weather-Based School Closure Prediction

Snow Day Calculator Denver — Will Schools Close Tomorrow?

🏛️ National Weather Service Data (USA)
🌍 Open-Meteo Forecast (Canada)
📍 Location-Based Prediction

Snow Day Calculator Denver

Enter your ZIP or Postal Code to check your snow day chance. Get a Snow Day Index score based on real weather data — specific to your region's closure patterns.

Checking weather conditions...
Locating your ZIP code
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Snow Day Index
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Calculating...

🍊 Confidence: --

Score reflects weather conditions vs your region's baseline closure threshold.
Not a statistical probability — see methodology.

Tomorrow's School Status Estimate

Based on Snow Day Index — not calibrated probability yet

Full Closure
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2-Hr Delay
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School Open
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⚠️ These splits are model estimates only. Closure vs. delay decisions depend on district policy, superintendent judgment, and conditions not fully captured by forecast data.

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Expected Snow
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Morning Feel
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Wind Speed
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Snow Timing
Why This Score

Each factor is scored independently — no double-counting

5-Day Snow Day Outlook

Index scores for the next 5 days · Accuracy decreases beyond 24hrs

Day Snow Index Signal

⚠️ Days 3–5 carry low forecast confidence. Use as early signal only — recheck daily as storm approaches.

Prediction History

How this prediction has changed as the forecast updates

Check back later — score history builds as you refresh predictions for this location.
Hourly Snowfall Forecast
Snow (in/hr)
Morning window (4–8 AM)
What If Scenarios

All scenarios calculated at once — see how each condition changes the score

↑↓ arrow keys · Enter to select · Esc to close
  • Tonight / Tomorrow
  • Day After Tomorrow
  • In 3 Days

ℹ️ Rural districts close at lower snow totals (longer bus routes). Private schools may set different thresholds. These are small adjustments — weather conditions drive the score.

Enter custom weather conditions to see how they affect the Snow Day Index score

❄️ Expected Snowfall 4 inches
🌡️ Morning Temperature (°F) 28°F
💨 Wind Speed (mph) 10 mph
🧊 Ice Accumulation 0 inches
⏰ Storm peaks during 4 AM – 8 AM window
⚠️ Blizzard / Winter Storm Warning active
🌧️ Freezing rain expected
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Adjust the sliders above

🗺️ Live Weather Maps

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How the Snow Day Index Works

The score is not a statistical probability — it's a structured index built from weather conditions compared against your region's baseline closure thresholds. Each variable measures something independent. We designed the algorithm to avoid double-counting the same conditions twice.

🌨️ Snowfall vs Regional Threshold (0–40 pts)

The biggest factor. Snowfall is scored against your region's typical closure threshold — not a flat national scale. 4 inches in Atlanta scores higher than 4 inches in Buffalo because Atlanta's threshold is lower. The region is built into this variable, not applied as a separate multiplier afterward.

⏰ Storm Timing (0–25 pts)

Measures only when the storm falls, not how much. A small storm peaking at 4 AM scores higher timing than a large storm at noon. This is completely independent from snowfall amount.

🧊 Ice / Freezing Rain (0–20 pts)

Scored separately from snowfall because ice is a different hazard. Even 0.1 inches of freezing rain is more dangerous than 6 inches of snow. This variable only activates if freezing rain is detected — it cannot overlap with V1.

🌡️ Extreme Cold / Wind Chill (0–15 pts)

Cold-day closures are a completely separate mechanism. Wind chill below -10°F can close schools with zero snow. This variable is not correlated with snowfall — it only contributes in genuinely extreme cold conditions.

⚠️ NWS Alert — Floor, Not Bonus

This is the most important design decision. NWS alerts are issued because of the same storm already measured in V1–V3. Adding alert points on top would count the same storm twice. Instead, alerts set a minimum floor — if the weather score is already higher, the alert adds nothing.

📊 Future Calibration

We collect actual school closure outcomes via the feedback button. Once we have enough data, we can compare score buckets to real closure rates — converting the index into a genuinely calibrated estimate. The methodology section will show this data publicly as we collect it.

Regional Closure Thresholds

Different regions have different infrastructure, plow capacity, and experience with snow. These thresholds are baseline estimates — not arbitrary coefficients — and will be updated as outcome feedback data accumulates.

Region Closure starts at Almost certain at
Deep South (AL, MS, GA, TX, LA)1"3"
Mid-South (NC, VA, TN, KY)2"5"
Pacific NW (WA, OR)2"5"
Mid-Atlantic (DC, MD, NJ, DE)3"7"
Mountain West (CO, UT, WY, MT)5"10"
Northeast (NY, MA, CT, PA)4"9"
Midwest (OH, IN, IL, MO)4"9"
Upper Midwest (MN, WI, MI)6"12"
Great Lakes (Buffalo, Erie, Cleveland)7"14"
🍁 CANADA
British Columbia (Vancouver)3"7"
Ontario (Toronto, Ottawa)8"16"
Quebec (Montreal, Quebec City)9"18"
Prairie Provinces (Calgary, Edmonton, Winnipeg)10"20"
Maritime Provinces (Halifax, Fredericton)10"20"

Data Sources

🇺🇸
USA

National Weather Service

The same government source superintendents reference when making closure decisions. Free, authoritative, and updated every 1–3 hours.

NWS • Official US Source
🇨🇦
Canada

Open-Meteo (ECMWF)

A free and accurate international weather service using the ECMWF global forecast model. NWS only covers the United States.

Open-Meteo • ECMWF Global Model

⚠️ The Snow Day Index is a decision-support tool, not a guarantee. School closure is a human decision made by your local district administrator. Always check your district’s official notification system for the final word. Forecast accuracy decreases significantly beyond 24 hours.

Frequently Asked Questions

How accurate is this snow day calculator?
Our predictions are based on real weather forecast data and a weighted scoring model that considers snowfall amount, timing, temperature, precipitation type, and your region's closure patterns. For USA locations, we use National Weather Service (NWS) data. For Canadian locations, we use Open-Meteo (ECMWF model). Short-term forecasts (12–24 hours) are most reliable. Predictions 48–72 hours out carry higher uncertainty and should be treated as early signals only.
Does this work for Canadian postal codes?
Yes. Enter your postal code (e.g. M5V 3A8 or M5V3A8) and the calculator will fetch weather for your area using Open-Meteo's global forecast model and apply Canada-specific regional closure thresholds. Canadian provinces have much higher snow tolerance than most US regions — Toronto and Ottawa typically close only at 8"+ accumulations, while the Prairie provinces (Calgary, Winnipeg) close even less frequently for snow alone.
Why does the same snow amount mean different things in different states?
Infrastructure and experience vary dramatically. Buffalo, NY maintains large plow fleets and handles 6 inches routinely. Atlanta, GA has a fraction of that equipment — 2 inches can shut the city down. Our regional closure thresholds account for this difference. These are baseline estimates — they will be refined over time as actual outcome data is collected through the feedback system.
Can freezing rain cause a snow day without much snow?
Yes. Even 0.1–0.25 inches of ice is more dangerous than 6 inches of ,255,0.8)">Mountain West (CO, UT, WY, MT)5"10" Northeast (NY, MA, CT, PA)4"9" Midwest (OH, IN, IL, MO)4"9" Upper Midwest (MN, WI, MI)6"12" Great Lakes (Buffalo, Erie, Cleveland)7"14" 🍁 CANADA British Columbia (Vancouver)3"7" Ontario (Toronto, Ottawa)8"16" Quebec (Montreal, Quebec City)9"18" Prairie Provinces (Calgary, Edmonton, Winnipeg)10"20" Maritime Provinces (Halifax, Fredericton)10"20"

Data Sources

USA: Weather data comes from the National Weather Service (NWS) — the same government source superintendents reference when making closure decisions. Free, authoritative, updated every 1–3 hours. Canada: Weather data is provided by Open-Meteo (ECMWF global forecast model), a free and accurate international weather service. NWS only covers the United States.

⚠️ The Snow Day Index is a decision-support tool, not a guarantee. School closure is a human decision made by your local district administrator. Always check your district's official notification system for the final word. Forecast accuracy decreases significantly beyond 24 hours.

Frequently Asked Questions

How accurate is this snow day calculator?
Our predictions are based on real weather forecast data and a weighted scoring model that considers snowfall amount, timing, temperature, precipitation type, and your region's closure patterns. For USA locations, we use National Weather Service (NWS) data. For Canadian locations, we use Open-Meteo (ECMWF model). Short-term forecasts (12–24 hours) are most reliable. Predictions 48–72 hours out carry higher uncertainty and should be treated as early signals only.
Does this work for Canadian postal codes?
Yes. Enter your postal code (e.g. M5V 3A8 or M5V3A8) and the calculator will fetch weather for your area using Open-Meteo's global forecast model and apply Canada-specific regional closure thresholds. Canadian provinces have much higher snow tolerance than most US regions — Toronto and Ottawa typically close only at 8"+ accumulations, while the Prairie provinces (Calgary, Winnipeg) close even less frequently for snow alone.
Why does the same snow amount mean different things in different states?
Infrastructure and experience vary dramatically. Buffalo, NY maintains large plow fleets and handles 6 inches routinely. Atlanta, GA has a fraction of that equipment — 2 inches can shut the city down. Our regional closure thresholds account for this difference. These are baseline estimates — they will be refined over time as actual outcome data is collected through the feedback system.
Can freezing rain cause a snow day without much snow?
Yes. Even 0.1–0.25 inches of ice is more dangerous than 6 inches of snow on roads. Ice cannot be plowed and road salt loses effectiveness below 15°F. Ice-related closures are common even with minimal snow accumulation.
When do schools usually announce closures?
Most school districts make the call between 4:30 AM and 6:00 AM on the morning of a potential closure. For large, clearly severe storms, some districts announce the evening before. Always check your district's official notification system for the final decision.
Does extreme cold alone cause school closures?
Yes. Wind chill below -15°F to -20°F is a standalone closure trigger in many northern districts. Students waiting at unsheltered bus stops face frostbite risk even with no snow at all.
What is the difference between a snow day and a 2-hour delay?
A 2-hour delay gives road crews extra time to clear routes before buses deploy. Districts choose this when conditions are expected to improve enough by mid-morning. A full closure means the district determined conditions will not be safe for the entire school day.
57"Average Annual Snowfall
5,280 ftElevation — Mile High City
300Sunny Days Per Year
72,000+Denver Public Schools Students

How the Denver Snow Day Calculator Works

Denver’s winter weather is unlike any other major US city. Sitting at 5,280 feet on the eastern edge of the Rocky Mountains, Denver can go from 60°F and sunny to a full blizzard in under 24 hours. Our Snow Day Calculator pulls real-time weather data for Denver CO and the Front Range metro, analyzing snowfall forecasts, temperature swings, ice risk, storm timing, and road conditions to generate a school closure probability for your ZIP code.

Denver Public Schools serves over 72,000 students across the city, while the broader Front Range metro includes major independent districts — Cherry Creek, Jefferson County, Aurora, Boulder Valley — each making their own closure decisions based on local conditions. Enter your ZIP code for a localized estimate — but the official call always comes from your district.

Why Snow Days Are Different in Denver

Rocky Mountain Weather Can Change Quickly

Denver’s location on the Front Range — where the Great Plains meet the Rocky Mountains — creates some of the most volatile winter weather in the country. Upslope storm systems are the primary snow producer: when moist air from the east gets pushed up against the mountains, it cools rapidly and dumps heavy snow on Denver and the foothills. These storms can develop quickly and are notoriously hard to forecast. A storm predicted to drop 3 inches may deliver 12. That uncertainty is why checking the calculator close to storm time matters.

Upslope Storm Systems

Upslope storms track in from the east and are amplified by the mountains. They produce Denver’s heaviest snowfalls — sometimes 12 to 20 inches — and are the most likely events to close schools across the entire metro.

Rapid Temperature Swings

Denver is famous for dramatic temperature changes. A Chinook wind off the mountains can raise temperatures 40°F in hours, melting overnight snow. But storms can also drop temperatures 30°F in minutes, freezing wet roads instantly.

High Altitude Dry Snow

Denver’s elevation produces lighter, drier snow than coastal or Midwest cities. This snow moves easily in wind, causing significant drifting and blowing, but also melts faster when the sun comes out after a storm.

Freeze-Thaw Ice Hazard

Denver’s frequent temperature swings above and below freezing create dangerous freeze-thaw cycles. Melted snow refreezes overnight as black ice on residential streets, making morning conditions hazardous even after a storm has passed.

Snowfall Patterns Along the Front Range

Denver averages about 57 inches of snow per season, but distribution is highly uneven. March is often the snowiest month — a reversal from most northern cities where January dominates. Denver can see major storms in October and April, making it one of the longest potential snow seasons of any major US city. Snowfall also varies considerably across the metro: elevated neighborhoods like those near the foothills can get significantly more snow than lower-lying eastern suburbs during the same storm.

Temperature Swings Affect School Decisions

What makes Denver snow day decisions complex is the unpredictability of conditions from storm to storm. A 6-inch snowfall at 28°F on a clear morning may result in school opening normally after road treatment. The same 6 inches during an ongoing storm with temperatures dropping into the teens and wind creates an entirely different risk profile. Superintendents weigh storm timing, temperature trajectory, and road clearing capacity — not just accumulation totals.

How Denver Schools Decide Snow Days

Denver Public Schools and Front Range district superintendents monitor weather forecasts and CDOT road condition reports through the night before a potential closure. Key factors: projected snowfall totals, storm timing relative to school start, overnight temperature trajectory, road clearing status, and morning road condition reports. Most districts announce by 5:30–6:30 AM.

Denver Public Schools

DPS serves 72,000+ students across Denver. Closure decisions are communicated via the DPS website, 9NEWS, CBS Colorado, ABC7, and automated parent notifications. DPS weighs road conditions citywide, including residential streets in all neighborhoods.

Cherry Creek Schools

One of Colorado’s largest districts, serving southeast metro communities including Centennial and Aurora. Cherry Creek makes independent decisions and often aligns with DPS on major storm days but may differ on borderline events based on their suburban road conditions.

Jefferson County Schools

Jeffco serves the western Denver suburbs including Lakewood, Arvada, and Wheat Ridge. Proximity to the foothills means Jeffco schools sometimes see more snow than the city and may close when Denver remains open.

Aurora / Boulder Valley Schools

Aurora Public Schools covers the eastern metro and often experiences different storm totals than the city. Boulder Valley Schools, while farther north, is frequently affected by the same Front Range upslope events and makes its own independent closure decisions.

Weather Factors That Affect Denver School Closures

Weather FactorLow ImpactModerate ImpactHigh Impact
Snow AccumulationUnder 3"3–7"7"+ (closure likely)
Storm TimingAfternoon / eveningOvernight into morningOngoing at school start
Ice / Freezing RoadsTrace amountsPatchy iceWidespread black ice
TemperatureAbove 28°F15°F to 28°FBelow 15°F with wind
Wind & DriftingUnder 15 mph15–30 mph30+ mph (blowing snow)

Snow Day Calculator vs Weather Forecast

A weather forecast tells you how many inches of snow are expected. The Snow Day Calculator translates that forecast — combined with temperature trajectory, ice risk, storm timing, and road conditions — into a school closure probability. In Denver, a storm that arrives at 2 AM and ends by 5 AM is much more likely to produce a closure than the same storm arriving at 10 AM. The calculator factors all of this in.

🏸 Storm Timing Is Key

In Denver, when the storm hits matters as much as how much falls. Check the calculator as the forecast sharpens — timing uncertainty is highest 48+ hours out.

❄️ Watch for Upslope Alerts

NWS upslope snow advisories and warnings for the Denver metro are a strong closure indicator. Our calculator weights active NWS alerts in the probability score.

📍 Foothills vs. Plains

Jeffco and west-side neighborhoods near the mountains can get dramatically more snow than eastern Aurora. Enter your specific ZIP code for the most accurate local prediction.

Denver Areas Covered by Snow Day Calculator

Our calculator covers Denver and the Front Range metro area, including: Aurora, Lakewood, Arvada, Westminster, Boulder, Littleton, Centennial, Englewood, Thornton, Parker, and Castle Rock. Enter any Denver metro ZIP code for a localized snow day prediction.