SSC Weather-Type Frequency Explorer

• Frequency is the percentage of valid classified days in the selected period assigned to the selected SSC type.
• Main-type totals include their “+” subsets. Selecting a “+” type analyzes only that subset.
• Years with missing classifications are hatched; years below 80% completeness are faded and excluded from the mean, record, trend, and decade summaries.
• The fitted line is an ordinary least-squares linear trend across eligible years in the selected range.
• Trend significance uses a two-sided t test of the OLS slope at α = 0.05. A solid line and triangle indicate p < 0.05; a dashed line and open circle indicate p ≥ 0.05.

Source: SSC3 daily station calendars.