My professor gives the solution, as we can see at the site were the climatic variables came from http://www.worldclim.org/formats1:

"Please note that the temperature data are in °C * 10. This means that a value of 231 represents 23.1 °C. This does lead to some confusion, but it allows for much reduced file sizes which is important as for many downloading large files remains difficult. The unit used for the precipitation data is mm (millimeter)."

thanks anyway!!!

My professor gives the solution, as we can see at the site were the climatic variables came from http://www.worldclim.org/formats1:

Please note that the temperature data are in °C * 10. This means that a value of 231 represents 23.1 °C. This does lead to some confusion, but it allows for much reduced file sizes which is important as for many downloading large files remains difficult. The unit used for the precipitation data is mm (millimeter).

(Edited in by Gerrit): storing (climate) data with offsets and scale factors to reduce file size is common practice, as scaled integers can easily be less than half the size of floats. When data are stored in standard formats sch as NetCDF or HDF-5, there is probably a variable attribute documenting this. When data are stored in a homegrown format, check the documentation carefully for any mention of offsets and scale factors that need to be applied.