The LIS/OTD 2.5 Degree Low Resolution Diurnal Climatology (LRDC) 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 LRDC dataset include diurnal flash rate climatology data including raw and scaled flashes on a 2.5 degree grid in HDF and netCDF-4 format.