Airgram symbols

[gelu]

Do we have a legend for all the symbols used in the airgram that we can refer to?

I see some small round symbs attached to the lines of barometric height and used to associate these with humidity in the air, but still confused
Please see the attached: Screenshot (28).png

[vsinceac]

Small circles should be for "Calm Winds"; see more details on wind barbs in this post or this one.