Jasmines do in fact bloom during the day as well (dependant on
the type of Jasmine), the scent of the flower is more prevalent at
night. The flower has a long Trumpet shape normally attracts moths
(at night) or butterfly's (during the day) for pollination.
Flowers that bloom at night are trying to attract night flying
insects and animals to pollinate them. Such flowers are usually
pollinated by moths and (strangely enough) by bats.
The 200 species of the jasmines are native to the tropical and
temperate regions of the Old World. See the Related Link posted
below for more information: