The climate for the central Portugal region is dominated by Atlantic weather patterns and as such is generally a few degrees cooler than the mediterranean regions further to the South.
In general you have defined seasons. with the summer months usually being very hot and dry.
It can be cool in the winter months at night, however the temperatures soon rise as the sun rises.
The Central Portugal area tends to be green and most of the rain tends to fall during the winter months from November to February.