In Scala, how do I fold a List and return the intermediate results?

I've got a List of days in the month:

val days = List(31, 28, 31, ...)

I need to return a List with the cumulative sum of days:

val cumDays = List(31, 59, 90)

I've thought of using the fold operator:

(0 /: days)(_ + _)

but this will only return the final result (365), whereas I need the list of intermediate results.

Anyway I can do that elegantly?