Will I be cold?
Will I be cold in San Diego in June?
Verdict
No — No, comfortable.
Lows stay near 64°F — you won't be reaching for the puffer.
Day vs. night
Day
77°F
Warm
Breathable fabrics; sunscreen matters more than a jacket.
Night
64°F
Comfortable
Comfortable outside without an extra layer.
Why
San Diego in June averages highs of 77°F, lows of 64°F, 0 rainy days.
You can pack for the daytime temps and not worry about the evening dip.