The AWSSI is not limited to meteorological winter (December ‐ February) but is intended to capture winter weather from its earliest occurrence to its last. The winter season begins when the first of any one of the following instances occurs:
First measurable snowfall (>= 0.1 inch)
• Maximum temperature at or below 32°F
• December 1
The winter season ends at the last occurrence of any of the following:
• Last measurable snowfall (>= 0.1 inch)
• Last day with 1 inch of snow on the ground
• Last day with a maximum temperature of 32°F or lower
• February 28/29
Daily scores are calculated based on scores assigned to temperature, snowfall, and snow depth thresholds. The daily scores are accumulated through the winter season, allowing a running total of winter severity in the midst of a season as well as a final, cumulative value characterizing the full season. Accumulations of the temperature and snow components of the index are computed separately and then added together for the total index. This allows comparison of the relative contribution of each to the total score.
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