H Mags,
Hope its Spain as I'm there in March, not with JY on this trip but doing it independant. Looking at history average temperatures are 15c with highs in the low 20's. Actually staying at Nerja which is one of the JY excurrsions.
Did the Andalucia trip a few years back and enjoyed it, thought all the excurrsions were good.
Istanbul usually hasn't warmed up by then and the historical March average is only 8c, with highs only reaching 11c.
Mick