mumymasti lujvo

x1 is May/the fifth month of year x2 in calendar x3.

Duration. For date, use masnmu. Cf. pavmasti, nanca.

In notes:

bakma'i
m1 is May of year m2 in calendar m3.
pavmasti
x1 is January/the first month of year x2 in calendar x3.
mumymast
May.