The weather is unpredictable most of the year, so you should be prepared for rain (particularly in Galicia), day-time heat and cold nights, especially at high altitude. 

The summer months can be extremely hot, especially on the meseta, the high and very exposed plain between Burgos and León on the Camino Francés, and on the more southerly sections of the Via de la Plata.  Seville is especially hot, with summertime temperatures in the 30’s and regularly reaching the high 20s in May and October.

See our publication "The Winter Pilgrim" for advice on doing the camino in winter months.

French weather forecasts

Spanish weather forecasts

Portuguese weather forecasts

For a truly formidable array of weather information covering most of Europe, though especially Spain -http://web.archive.org/web/20080312184613/groups.msn.com/ElCaminoSantiago/weather.msnw  

And visit the Pilgrimage to Santiago Forum for up-to-the-minute exchanges about the weather.