SSC Historical Maps

Map daily classifications or compare SSC-type frequencies across stations in a selected geography.

Geography

State / province

Map display

Date

Year

Period

SSC type

Preparing station directory…

Available SSC stations

Methodology and data notes

Each marker is an individual SSC station; the displayed values are not spatially interpolated.
Frequency is the share of valid classified days assigned to the selected type. Main types include their “+” subsets.
Periods with more than 20% missing classifications are omitted, and stations without usable data are not displayed.
December–February is assigned to its ending year.

Source: SSC3 daily station calendars and the overnight period summaries.