Here in Canada, we like to use the Remarks section in a METAR. Take a look at this example:

CYYZ 280200Z 36007KT 15SM FEW040 FEW120 BKN230 22/16 A2987 RMK SC1AC2CI1 SLP112

The stuff after RMK is the type of cloud cover, and the sea level pressure in milibars. So in the example above the sky is covered with:

1/8th Strato Cumulus
2/8th Alto Cumulus
1/8th Cirrus

And the sea level pressure would be 1012.5 milibars.

Automated weather stations aren’t able to determine the type of cloud cover. Previously they’ve usually just put the sea level pressure in …