right bin edge is inclusiveso the : value is included in the : to : interval passing closed='leftchanges the interval to be closed on the leftin [ ]ts resample(' min'how='sum'closed='left'out[ ] : : : : : : freq as you can seethe resulting time series is labeled by the timestamps from the right side of each bin by passing label='leftyou can label them with the left bin edgein [ ]ts resample(' min'how='sum'closed='left'label='left'out[ ] : : : : : : freq see figure - for an illustration of minutely data being resampled to five-minute figure - -minute resampling illustration of closedlabel conventions lastlyyou might want to shift the result index by some amountsay subtracting one second from the right edge to make it more clear which interval the timestamp refers to to do thispass string or date offset to loffsetin [ ]ts resample(' min'how='sum'loffset='- 'out[ ] : : : : : : : : freq the choice of closed='right'label='rightas the default might seem bit odd to some users in practice the choice is somewhat arbitraryfor some target frequenciesclosed='leftis preferablewhile for others closed='rightmakes more sense the important thing is that you keep in mind exactly how you are segmenting the data resampling and frequency conversion www it-ebooks info