There are some of us who normally do not crave warmer temperatures and I consider myself among those. My parents were much the same as is my brother and others who I know. With us, anything much above 20° C hardly is desired and triggers a kind of hibernation during heatwaves.
In my case, it also has meant that I often had headed north for summer getaways. Scotland has featured a lot, as much for its scenic delights as for the ability to leave my normal way of life after me for a while. In the last two years, it has become more obvious with my rejection of continental summer temperatures for the relative cool of Iceland and Norway. That walking is much of what I do for relaxation means that scorching temperatures are not so compatible anyway.
For alpine wanderings, I chose what I saw as shoulder seasons such as spring for Austria and autumn for Switzerland. Still, I still met up with temperatures in the mid to high twenties around Innsbruck yet I found, that by going higher, it was easy to escape these though cable car travel saves your sweating on the way uphill. It was a reminder that higher level alpine walking is a way of escaping heat as much as would going to the coast in more maritime localities.
In contrast, many heat lovers head south during the winter and there always is the southern hemisphere where they have their summer. In between, the milder winters of southern Europe suffices for those of us fancying a warmer escape from frosty weather that is not overly hot. In fact, such is the heat that some of those places get in summer that walking becomes a autumn, winter and springtime activity.
You might be tempted to think that applies to places like the Canary Islands, Madeira or the Azores but much of Spain, Italy, Croatia and Greece is likewise. It may come as a surprise to some but places normally associated with sun, sand and sea have their delightful stretches of nearby hill country too. That makes them possibilities for for warmer winter walking getaways. Mallorca and Corsica may have fleshpot reputations but going elsewhere on those islands brings you to dramatic craggy terrain.
The same applies to the south of Portugal, Spain and Italy. There are places in the hills not far from the Algarve, the Costa Blanco and the Costa del Sol have a wilder and less developed feel. Winter is low season too so whatever hotels are open may give you better deals depending on when you go. It may feel odd to base yourself somewhere geared up for more sedentary or hedonistic pursuits when you are after more wholesome country walking but it can be made to work.
Coming a little further north, I even considered Catalonia, Tuscany and Umbria too as I surveyed places that I otherwise would not consider. Given the reputations of some and my need for restorative quieter breaks, that may not be such a surprise. With a different time of year, different needs can be fulfilled and year round popularity makes for simpler travel arrangements even in the off season too.