You specify +/- 1mG/°C.
If the temperature increase of 10°C, how can he knows if it'll be an increase
or a decrease ?
More over is offset change similar between two accelerometers ?
The 0g offset temperature drift is defined as the output change from ambient to
maximum temperature or ambient to minimum temperature. The 0g offset drift with
temperature is specified as 1mg/degC typical. So, over the -40 to +85degC
temperature range, you would expect the offset to vary by 125mg. However, this
is a typical spec so you may have parts with a drift which is greater than
1mg/degC. See distribution graphs on page 7 of the datasheet and also on the
same page, 0g bias v temperature graphs for each axis.