Check out the general 5-day weather forecast below in Galicia or click on the following links to read the 5-day forecast for each individual province. An overall summary of the weather in Galicia throughout the year is provided at the end with brief advice on what to pack on your travels here. Being northern Spain expect some rain no matter what month it is. Temperatures in summer on the coast are pleasantly warm but rarely too hot but inland they can soar especially in Ourense to some of the highest in the whole of Spain. Conversely in the mountainous interior it can snow quite a bit in winter. Generally the weather is relatively similar to other northern european countries allbeit a little warmer. There are signs that temperatures are slightly rising overall due to global warning.
Galicia has an North Atlantic climate due to its western and northern coastline that becomes more mediterranean further inland.
Galicia can be a wet and humid region in winter although it's generally relatively mild. Inland, and especially in mountainous areas, winters are however colder. So you will need to wrap up warm and wear water-proof clothing.
Summers which are the best time to visit Galicia are usually hot and drier especially in the more sheltered southern part of the Rias Baixas. Inland temperatures in places like Ourense frequently soar to 30ºC or above. It is still advisable to bring a warmer change of clothing if staying out late.
The annual average temperature for the whole of Galicia is about 14ºC so generally temperatures are much more comfortable than many parts of southern Spain. Generally you can expect pretty good weather and pleasent temperatures from March through to the end of October where normally during the day you can walk around with shorts and light clothing. Don't forget the sunglasses,sun tan cream and light raincoat just in case.
Average Temperatures (Source Spanish Meteorological Office)