Historic yield curves
Overlay US and Canadian government curves from any date in the history. Each curve can use one day, the average of that calendar month, or the average of the trailing 30 days.
Specific day uses the last print on or before the date. Calendar month averages every print in that month. Trailing 30 days averages prints in the 30 calendar days ending on the date. A dotted stretch is a straight line across a missing tenor.
8 curves is the maximum.
These notes describe the US Treasury curve. Adding one places that month's average on the chart. Hover a name for the shape and why it mattered.