Below is a brief outline of what to expect on the Camino de Santiago for each month of the year.
Further Reading:
Camino de Santiago in January
Very cold and wet in some parts of the Camino and not many people to travel with you.
Camino de Santiago in February
Still very cold in many places, though not as bad as January. Some travelers.
Camino de Santiago in March
Weather is cool but not unpleasant. More travelers now on the route. A very good time to walk.
Camino de Santiago in April
Weather can be be quite warm in some places now. More and more travelers on the route.
Camino de Santiago in May
Could be very hot in May, though weather varies more on northern Spain than it does in other parts of the country. Route is getting quite busy now. Some hostels may be full by the time you get to them.
Camino de Santiago in June
Hot weather can be expected. There is reportedly a slight dip in 'traffic' in June compared to May, though still more than in April.
Camino de Santiago in July
Very hot and lots of other travelers. Can you cope with the sweaty people who haven't showered for days (because the line for the shower was too long)?
Camino de Santiago in August
Similar to July.
Camino de Santiago in September
Getting cooler now, but not by much. Still lots of travelers.
Camino de Santiago in October
Weather much more pleasant now. Crowds dying away.
Camino de Santiago in November
Quite cold on some parts of the walk. Very few people walking.
Camino de Santiago in December
Cold and extreme conditions possible. Not a good time to walk.