It’s a Snow Day! How Winter Weather Extremes Affect School Bus Cancellations

Abstract Winter weather extremes affect all forms of transportation including bus transport for children to and from school. Spatial differences in bus cancellations across school districts and their associated weather are important to quantify, as they can result in unequal educational outcomes if student learning is affected. This study compared winter (December–February, inclusive) cancellation frequency across 17 bus zones distributed across a broad latitudinal gradient (∼42.3°–49.8°N) in Ontario, Canada, over a 5-yr period (2014–19). Unexpectedly, we found that cancellation frequency was not consistently highest at sites located within the “snowbelt” zone, where winter precipitation is greatest. Instead, zones in the central latitudes (∼44°–46.5°N) had the most frequent cancellations (average 4.8–7.2 days per winter), with one board cancelling buses 13 days in a single winter. Cancellations were mostly associated with the incidence of “mixed precipitation,” inclusive of both rain and snow on the same date. Likewise, cancellations were more common in winters with more frequent freeze–thaw cycles. Our results point to the existence of a “slush zone” in Ontario, where average precipitation inputs and winter temperatures are high enough to allow rain to develop, cold enough to provide ample snowfall, and variable enough to allow both rain and snow to cooccur in mixed precipitation events. School buses in the slush zone are cancelled more than twice as frequently as southern areas of the province. Consequent differences in student attendance rates may ultimately affect learning outcomes and should be the subject of further study. Significance Statement School bus cancellations due to inclement winter weather vary widely across the province of Ontario, Canada, resulting in multiweek differences in student instructional days among jurisdictions. Future increases in winter weather extremes resulting from climate change may exacerbate these differences, especially between rural and urban school districts. These results will be of interest to educators and transportation managers, as uneven winter weather impacts may result in unequal academic outcomes.