Very low humidity yesterday
As a Brit, I'm not used to seeing the T/DP spread more than about 10 degrees.
The AWOS yesterday at Hawthorne (4 miles from the ocean) was:
KHHR 292153Z 00000KT 10SM CLR 27/M19 A3010 RMK AO2 SLP190 T02671189
A spread of 46 degrees and corresponding with about 4% relative humidity.
I guess it was due to the Santa Ana wind blowing in from the desert and heating the air as it descends.
Anyway, the flying was great, visibility incredible. Summer's arrived early in L.A.