Mild climate, low-humidity city all year round
Low humidity means nowhere near the coast or near any large lakes. Warm winter temperatures without being too hot in summer means tropical high elevation or lower latitude inland sub-tropical. Parts of sub-Saharan Africa might suit, although cities like Kampala or Nairobi have relative humidities which reach the high 70s. As Milancuric writes, you need to be more specific about 'low humidity'.