  Time series are presented for the class II methanol maser source G12.89+0.49,
which has been monitored for nine years at the Hartebeesthoek Radio Astronomy
Observatory. The 12.2 and 6.7 GHz methanol masers were seen to exhibit rapid,
correlated variations on timescales of less than a month. Daily monitoring has
revealed that the variations have a periodic component with a period of 29.5
days. The period seems to be stable over the 110 cycles spanned by the time
series. There are variations from cycle to cycle, with the peak of the flare
occurring anywhere within an eleven day window but the minima occur at the same
phase of the cycle. Time delays of up to 5.7 days are seen between spectral
features at 6.7 GHz and a delay of 1.1 day is seen between the dominant 12.2
GHz spectral feature and its 6.7 GHz counterpart.
