Hi Paige,
You can use GatherBy to gather them like so:
time = DateRange[{2017, 1, 1}, {2017, 12, 31}, 5];
amplitude = RandomInteger[5, Length[time]];
data = Transpose[{time, amplitude}];
GatherBy[data, Last]
If you used FindClusters, specify your data like this:
FindClusters[{a1->{t1,a1}, a2->{t2,a2}, a3->{t3,a3} .....}]