Downers Grove, Illinois, 4,708 students in 2 schools

Community High School District 99 Snow Day Predictor

Q: How much snow does Downers Grove get?

About 28.9 inches a winter at a NOAA weather station 2.3 miles away, averaged over 8 winters. Between December 1 and March 31 that brings 3.1 weekday mornings a year with 2 inches of new snow or more, and 0.6 with 4 inches or more.

Q: What was the biggest snow day near Community High School District 99?

5.6 inches on December 5, 2016, the largest single day at a NOAA weather station 2.3 miles away in 8 winters. The snowiest winter was 2018 to 2019, with 39.4 inches.

Q: Does Community High School District 99 get more snow days than other Illinois districts?

Community High School District 99 averages 0.6 weekday mornings a winter with 4 inches of new snow or more, more than 52 percent of the 788 Illinois districts with a station record.

Q: How does the Community High School District 99 snow day predictor work?

It reads the National Weather Service forecast for Downers Grove through the night and the 5 to 8 am bus run, adds winter alerts and the Winter Storm Severity Index, and measures the snow against Community High School District 99’s own big snow morning: 3.2 inches, the top tenth of snowy weekday mornings at a NOAA weather station 2.3 miles away.

The odds of a closing or a delay on the next three school mornings in Community High School District 99, measured against Community High School District 99's own big snow morning of 3.2 inches.

The next three school mornings

Will Community High School District 99 close tomorrow?

Reading the National Weather Service forecast for the overnight and the bus hours in Downers Grove.

Ten winters of school mornings

Community High School District 99’s snow record

28.9inches of snow a winter

3.1school mornings a winter with 2 in of new snow or more

0.6with 4 in or more

3.2 ina big snow morning in Community High School District 99: the top tenth of snowy school mornings

More 4 inch school mornings than 52% of the 788 Illinois districts with a station record.

2.5Nov

3.8Dec

9.7Jan

8.7Feb

2.1Mar

Average snowfall by month, inches

Biggest day 5.6 in on December 5, 2016
Snowiest winter 2018 to 2019, 39.4 in
6 in mornings 0 a winter
1 in mornings 5 a winter

Measured at a NOAA weather station 2.3 miles away. Mornings are the 7 am snow reading on a weekday from December 1 through March 31, over the ten winters from 2016 to 2017 through 2025 to 2026, from NOAA GHCN Daily.

The Illinois rule

How Illinois counts a lost day

Illinois requires a calendar of at least 185 days to guarantee 176 days of actual student attendance, each of at least 5 clock hours. The extra calendar days are emergency days used first; after they are gone, the State Superintendent may excuse days lost to an act of God or a hazard beyond the district's control without cutting state aid.

The Illinois rules in the agency’s own words, and every Illinois district

Next door

Districts near Community High School District 99

District	Snow a winter	4 in mornings	Built in days
Downers Grove Grade School District 58Downers Grove	22.9 in	0.5
Hinsdale Community Consolidated School District 181Clarendon Hills	28 in	0.5
Hinsdale Township High School District 86Hinsdale	27.5 in	0.5
Naperville Community Unit District 203Naperville	20.9 in	0.8	5
Lombard School District 44Lombard	32.3 in	0.9
Community Unit School District 200Wheaton	32.3 in	0.9

The schools

2 schools

Every school in Community High School District 99 follows the district’s call: one closing covers them all.

High

Comm H S Dist 99 - South High Sch
Comm H S Dist 99 - North H S

Questions

Community High School District 99 snow day questions

How much snow does Downers Grove get?

What was the biggest snow day near Community High School District 99?

Does Community High School District 99 get more snow days than other Illinois districts?

How does the Community High School District 99 snow day predictor work?

How does Illinois handle snow days?

More winter

More for Illinois snow days

Snow day predictorClosing and delay odds for any ZIP, with the snowiest districts in the country.Snow depth mapHow much snow is on the ground right now, measured, across the country.First snow datesWhen the first measurable snow usually lands where you live.Frozen pipesThe nights cold enough to freeze a pipe, and what to do before one.Snow plow trackerWhere the plows are during a storm, city by city.Illinois winter forecastThe season ahead for Illinois: snowfall, cold and the first snow.

A residential street under deep snow on a bright blue morning, cars parked along the curb buried into smooth white mounds, one set of tire tracks down the middle — The morning after a big one: cars buried to the mirrors and one set of tracks down the middle. A street like this is a closing, no debate. Photo, Fairfax, Virginia, January 2016: Jarek Tuszyński, CC BY 4.0

The odds are a forecast read, and the superintendent makes the call: the district’s own announcement is the one to follow.