The LIS/OTD 2.5 Degree Low Resolution Time Series (LRTS) contains a variety of gridded climatologies of total lightning flash rates obtained from two lightning detection sensors - the spaceborne Optical Transient Detector (OTD) on Orbview-1 and the Lightning Imaging Sensor (LIS) onboard the Tropical Rainfall Measuring Mission (TRMM) satellite. The long LIS (equatorward of about 38 degree) record makes the merged climatology most robust in the tropics and subtropics, while the high latitude data is entirely from OTD. The LRTS dataset include flash rate time series data in MP4 format.