Mary the good old wife of Richard Styreinge a shepheard
after a storme from xtmas till then was buryed – March xvth
si sol splendescat Maria Purificante Major erit glacies post festum quam fuit ante
It’s a comment on the weather, which had been very bad since Christmas until that day (15 March). Apart from referencing the date, it doesn’t relate directly to the burial, which just happens to be the last entry in the register for the year 1664/65 (the new year began on 25 March).
The Latin line is a common superstition about winter: if the sun shines at Candlemas [= Feast of the Purification, 2 Feb], the half of winter that is still to come will be colder than the half that has just gone.