How can it possibly be this hot in April?

Day 2 Sare to Ainhoa 9 miles
We tried to make an earlier start today and succeeded in part. An easy day was planned and we were raring to go, if a little stiff. At breakfast our host announced that it was already 20c - a result of the warm Mediterranean breeze blowing today. It usually brings rain but this time not til tomorrow evening. It's been a beautiful walk through the rolling countryside and a particularly pleasant stretch through trees and dappled shade along a stream by the Spanish border. Ainhoa, our halt for the night, is another really pretty basque village. We've showered, slept, eaten well, explored and are now melting as we try to get some sleep. We have to leave soon after 8 tomorrow to beat the heat and to get to tomorrow's farm up in the hill pasture before it 's too late for lunch as there are no supplies on tomorrow's route. It's a short etape of about 7 miles but there's a steep climb at the start. Will be worth it though as we get to spend the afternoon On the tops.