Two-Hour Delay Calculator
Will school start late tomorrow?
Enter your ZIP code or school district. The card shows the chance of a delay (school opens late or closes) and the chance of a closure, from tonight's National Weather Service forecast.
Loading tonight's forecast…
Snow by hour
From the National Weather Service forecast, updated hourly. Estimate only. Your district makes the call.
What usually causes a delay
- A few inches overnight that stop before dawn. Crews need a couple more hours, but the roads will be clear by mid-morning.
- A thin glaze of ice. Freezing drizzle or a quick refreeze makes untreated back roads and bus stops slick until salt and sun work.
- A bitterly cold morning. A later start moves bus stops out of the coldest hour around sunrise.
- A storm that ends late. If snow is still falling at 4 or 5 AM, a delay gives plows time to catch up.
A high delay chance with a low closure chance usually means the storm is over by morning. When both are high, the district may announce a delay first and close later. Snow day vs. delay vs. early dismissal.
How the delay chance is worked out
It is the same model as our snow day calculator, with lower lines, because it takes less weather to make a district start late than to close it:
- Snow: about half the overnight snow that would close schools in your area.
- Ice: a glaze of about 0.03 inches, versus roughly 0.12 to 0.2 inches for a closure (higher in snowier places).
- Cold: a wind chill at bus time about 5°F milder than the closing line.
These are our model's settings, not district policy, and they haven't been measured against real delays yet. How it works · Accuracy.
How much snow it takes for a delay, by city
Overnight snow where our model starts counting a delay, next to the snow that usually closes schools there (from each city's NOAA 1991–2020 snow normals).
| City | Delay likely from | Closure likely from |
|---|---|---|
| Syracuse, NY | 6.5 inches | 13 inches |
| Buffalo, NY | 5.5 inches | 10.5 inches |
| Cleveland, OH | 4.5 inches | 9 inches |
| Boston, MA | 4 inches | 8 inches |
| Denver, CO | 4 inches | 8 inches |
| Minneapolis, MN | 4 inches | 8 inches |
| Chicago, IL | 3.5 inches | 7 inches |
| Detroit, MI | 3.5 inches | 7 inches |
| Pittsburgh, PA | 3 inches | 5.5 inches |
| Philadelphia, PA | 3 inches | 5.5 inches |
| Charlotte, NC | 1.5 inches | 3 inches |
| Atlanta, GA | 0.5 inches | 1 inch |
Ice, wind chill and timing change the picture, so check your ZIP above for tomorrow's actual chance. More places: how much snow cancels school.
Two-hour delay questions
What is a two-hour delay?
School starts two hours later than usual, and morning programs such as early classes or morning kindergarten are often cancelled. Districts use it when roads should be safe after a few more hours of plowing, salting and daylight.
What's the chance of a delay tomorrow?
Enter your ZIP code above. The card shows two numbers from tonight's National Weather Service forecast: the chance your district closes, and the chance it at least delays the start (a delay or a closure). The delay chance is never lower than the closure chance.
How much snow does it take for a two-hour delay?
Less than for a closure. Our model starts counting a delay at about half the snow that would close schools in your area: around 4 inches where 8 closes school, and about half an inch in places that rarely see snow. A glaze of ice or a very cold morning can be enough on its own.
Can a delay turn into a snow day?
Yes. Districts sometimes announce a delay first, then close once crews have checked the roads in the early morning. If the card shows a high delay chance and a fairly high closure chance, keep an eye on your district's alerts.
When are two-hour delays announced?
Usually early in the morning, after crews have checked the roads and before buses leave, and sometimes the evening before when the forecast is clear. Only your district can announce one, through its website, text or phone alerts and local TV and radio.