Maybe Tyranitar is not such a Good Articuno counter after all.
These numbers were all formulated using GamePress numbers and custom formulas to get a rough estimate of the DPS. By no means am I saying this is exact.
Articuno Counters
Rock 2x
TyranitarAvg dps:29.83
TyranitarAvg dps:31.63
GolemAvg dps:39.65{Weak to all moves}
GolemAvg dps:44.57{Weak to all moves}
OmastarAvg dps:41.63{Resists all moves}
OmastarAvg dps:44.38{Resists all moves}
Electric 1x
JolteonAvg dps:34.26
JolteonAvg dps:36.39
Fire 1x
FlareonAvg dps:35.86{Resists all moves}
FlareonAvg dps:40.50{Resists all moves}
FlareonAvg dps:34.55{Resists all moves}
ArcanineAvg dps:30.56{Resists all moves}
ArcanineAvg dps:34.99{Resists all moves}
Steel 1x
ScizorAvg dps:36.35{Resistsall moves}