North County has many microclimates. For example, I lived in San Marcos in a west facing home on a slight hill and we had great ocean breezes. A mile away you could have a street that has a hill blocking the west breezes and temperatures can get as much as 5-10 degrees hotter in the summer with no breezes. San Elijo Hills gets great breezes, less cloud cover than areas near the coast, and temperatures are much cooler than areas on the other side of the hill in the same city. On my way back from Vegas last year I started looking at the outside temp at the 78/I-15 junction. It was 95 at the junction and it dropped 1-2 degrees every mile as I drove west.
IMO the best climate in the world exists in an area roughly 5 miles inland from the ocean and 5 miles west of I-15. Rancho Santa Fe, Vista, parts of San Marcos, parts of eastern Carlsbad/Encinitas etc. Not much coastal fog layer, much more sun, warmer but not too hot like areas further east, and you can still get ocean breezes. On days when it is foggy and 65 in coastal Encinitas, it is sunny and 72 in San Marcos.