Lower SW States in the Spring

If you want to avoid the heat, March is not too early to start, it may be too late. From N Fla to Ca is just over 2,000 miles; if you avg 200-250 miles per driving day, that's 8-10 days of driving. If you only drive every 3rd day, that's 30 days to get to Ca, plus 30 days back, plus whatever additional side trips you take. So 2 - 3 months overall is a good estimate. April is usually the month when the SW turns from warm to Hot. So I would want to be starting my return trip by April; meaning you should start the trip from Fla in early Feb, if you agree with the above, and ignore that its going to be Hot anyhow when you get back to Fla. Keep in mind we do have some significant elevation differences as you traverse the SW. We have what we call "high desert" areas where you may be up at over 4,000 ft elevation, with temps 10 degrees cooler than the lower desert areas 200 miles down the road. Which means in Feb/Mar some SW areas experience below freezing temps overnight. In southern NM where I winter, its not unusual to see 40 degree swings in the daily temps; warm sunny 70 degree days, followed by a 30 degree overnight low; or in Feb a 60 high and a 20 overnight low.