夜が涼しいときに散歩に行くことが多いよ

Meaning
i usually go for a walk at night when it's cooler

Vocab used in this sentence

night, evening
is, there, but, ga, will, however
涼しい
cool, refreshing, pleasantly cool, chilly
とき
when, time, moment, occasion, ibis
in, to, on, at, into, upon
散歩
walk, stroll, walk around, ramble
in, to, on, at, into, upon
行く
go, travel, move
こと
that, thing, about, fact, matter
is, there, but, ga, will, however
多い
many, often, lot, large, numerous, frequently, abound, plentiful
the, yo, ll