Between mid June and end September it's too hot to walk below 2000m. The high Sierra Nevada is great though. Pleasant and cool, high altitude trekking and hiking.
Give us a shout if you are in the Granada or Alpujarras region! We are usually available for walking and trekking year round and, in the 6 winter months from November to May, we offer winter mountaineering, snowshoeing and ski touring.