annual
biannual
biennial
bimestrial
bimonthly
biweekly
biyearly
cyclic
daily
day-after-day
day-by-day
day-to-day
diurnal
fortnightly
half-hourly
half-yearly
hebdomadal
hebdomadary
hourly
midweekly
monthly
nightly
oscillating
oscillatory
periodical
semestral
semestrial
semiannual
semimonthly
semiweekly
sporadic
triennial
weekly
yearly
alternate
articulated
beating
catenated
ceaseless
centennial
circling
concatenated
connected
constant
continual
continued
continuing
continuous
cyclical
direct
editorial
endless
episodic
epochal
even
ever-recurring
every other
featureless
fluctuant
fluctuating
fluctuational
frequent
gapless
harmonic
haunting
immediate
incessant
interminable
intermittent
isochronal
isochronous
iterative
joined
jointless
journalese
journalistic
libratory
linked
magazinish
magaziny
measured
period
periodicity
impending
occasional
ongoing
random
seasonal
subsequent
successive
timely
melodic
rhapsodic
aperiodic
irregular