i might be able to shed some light on the mulholland pass anomaly. In Los Angeles, as well as other areas charactarized by cold ocean water (such as san francisco), there is commonly a temperature inversion near coastal areas. Basically the cold air near the ocean slips in under the already present air since it is cold in a relatively thin layer over the water. This results in a lot of cool air sitting over coastal LA with warmer air above it. This is also what brings the low clouds and fog in. The inversion is usually at the top of the fog layer. (its called an inversion cuz temperature usually decreases with height). Anyway, the inversion washes in and if its pretty shallow it cant make it over the hills so it backs up agains the Santa Monica Mountains, where sepulveda pass is. when you drive over the top and down the south side you end up driving into the inversion, and also a lot of smog sometimes - the inversion tends to trap it down there. Its a pretty notable difference, it can be over 90 in the valley and still in the 60s along the beach. I'm not sure if its exactly the same in Berkeley becuase i havent spent much time there.. but id imagine its a similar effect

i've noticed similar effects even more localized out in the high desert near bishop at night. the cold air settles in little creek valleys, and the vegetation there causes evaporation which cools the air even more. So on a hot summer night you'll be driving down the desert with the windows down, drive past a little creek in a little valley, and itll suddenly cool off by like 20 degrees. then it warms up again on the otehr side.. its a pretty neat effect