Dataset

1. About data

Temperature mean, max and min for 5×5 grid over all of the earth:

> The Global Historical Climatology Network (GHCN-Monthly) data base contains historical temperature, precipitation, and pressure data for thousands of land stations worldwide. The period of record varies from station to station, with several thousand extending back to 1950 and several hundred being updated monthly via CLIMAT reports. The data are available without charge through NCDC’s anonymous FTP service.

1. Format

In .dat format.

1. License

From .gov site, and US government department, so one would assume a fair amount in the public domain. However, data is aggregated and includes non-US sources, so this should be clarified.