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.

I've seen similar things in Colorado, indeed right now in the Springs it's 03/M13and I bet the viz is fantastic and the hills have snow.

We don't get the same at Gatwick though 01/M01 and it's snowing (a bit).

Out of curiosity what is all the stuff at the end of US METARS? I understand RMK is "remarks" but what is all the stuff afterwards?

Surface Pressure Level 1019 HPa, Temperature +26.7C, Dewpoint -18.9C

It's a bit oddly coded though. And AO2 simply means the second generation of some sort of Automatic Observation machinery.

AO2 means the station has a precipitation discriminator, SLP190 is the pressure in millibars (1019). As for the rest, who knows....


edit-Backpacker knows!

Technically, with the DP below freezing, it would become a frostpoint.