sə̇ˈrät ə nəl, seˈr-; |serə|tīn ə l adjective
Etymology: Latin serotin us coming late + English -al — more at serotine
: of or relating to the latter and usually drier part of summer : occurring in the latter half of summer
a serotinal generation of aphids
ponds … drying up about the beginning of the serotinal season — Ecology