Spatial Synoptic Classification

"The SSC is based solely on surface based observations at an individual station. Four-times daily observations of temperature, dew point, wind, pressure, and cloud cover are incorporated into the model. It does not take upper-level conditions into account, and does not concern itself with the origin of the air above a station, though there are obvious correlations. Hence, the SSC is most properly called a weather type classification and not an air mass classification system.

Within the SSC scheme, weather-type characteristics change from station to station and day to day. Thus, a Moist Tropical weather type is hotter and more humid in the southeastern US, nearer its source region, than in the northeastern US, after it has modified somewhat. Similarly, MT is warmer at all locations in July than in January. (...)

On this website, SSC 'calendars' are available for nearly 400 stations across the US, Canada, and parts of Europe. The European calendars are limited to 1974-2000, but the US and Canadian calendars generally cover a station's total period of record. A total of over 8,000,000 days have been classified across all of these stations. The SSC is also being continually updated - you can see yesterday's (preliminary) classifications and today's and tomorrow's forecast classifications as well. The 'official' SSC calendar for a year will be added to this site within a couple of months of the calendar year's end."