Calends was a Roman "calendrical" word. The calends (or kalends) was the first of the month, from which dates were reckoned backwards, as "three days before the calends of July", and counted back as far as the ides of the previous month.

The ides was the other signpost of each month, which floated to different dates in different months, and dates would also be counted as so many days before the ides of the month. The ides of March (which Caesar was told to beware) is on the 15th, but the ides falls on other dates in other months.

Calends has nothing specifically to do with spring.

Dave Oesterreich