San Diego Transition - Temperature Averages Chart
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Max
66°
68°
70°
74°
74°
85°
91°
92°
87°
83°
75°
67°
Min
39°
39°
41°
44°
50°
54°
59°
59°
56°
49°
42°
37°
In the transition zone, the mercury can climb into the 90s with pleasant average high temperatures from November until May. Interestingly, Ramona experiences some of the lowest winter temperatures, dropping down as low as 37 degrees in December.
You can expect that only on rare occasions will the temperature drop down below 50 degrees in most regions, even at night.