The radiation symbol looks a bit much like an old fashioned computer tape reel, but I doubt there is much that can be done about that. Maybe lightning the outer circle to the stroke weight of the skull and bones will help, along with lengthening the fan blades.

Making the ring a little larger in the biohazard symbol might make it read better.

Very nice skull and bones. The teeth are going to be reduced beyond recognition at text sizes but the rest should hold up.

I quite often see a rain cloud (cloud with slashes underneath) on the local weather reports instead of an umbrella. Does Unicode specify “umbrella” for that position or just “rain” (or are you making this set up without regard for established Unicode symbols)? You’ll need a black cloud with a lightning bolt dropping from it for thunderstorms, if you don’t have one already. I’ll have to defer to people who live with snow for an opinion on the snowman vs. snowflake controversy.

Back up to your first two rows, the planetary symbols seem just fine but some of the others seem a touch too light. I’m a bit rusty on which of those is which, though.

The unicode does seem to specify a snowman and an umbrella. But it just seems like a symbolic mistake, if what is intended is the meterological conditions “rain” & “snow”. But I am not 100% clear how they are used. Maybe I am grouping unlike things...

Maybe I will reduce the # of teeth on the skull. The radiation symbol is set, as is the biohazard but I think they could be tweaked in the ways you suggest.

The lighter astronomical symbols are meant to be lighter than the main symbols but my question is “how much is ideal?”. I may be sweating some of this too much but I want to make this as fine as I am able to.

Most of those look too much too small to work at the same point size as the alphanumeric characters.
Why not do them double width?

Why do we not use a rain cloud instead of an umbrella and a cloud with snowflakes or simply a snowflake rather than a snowman?

For the same reason some people still use Helvetica as a neutral type: some important modernist said so, someone else wrote it down, and now it’s gospel.

What would you think about substitutes?

It’s about time.

Thus saith Tschichold:
“I dunno, you think maybe we should use an umbrella or somethin’?”

Thus saith Meggs:
“Tschichold recommended that umbrellas be used.”

Thus saith anonymous design agency:
“If Tschichold says that it must be an umbrella, then by God, who are we to question? An umbrella it must be.”

“Why not do them double width?”

Hmm that’s an interesting idea. Isn’t that cheating somehow? I guess it won’t break anything...

Double width characters will break columnar alignment, making ASCII art unreliable at best.
I’m sure there is a more important reason for it to be a bad idea to include double-wide glyphs in a monospace font, but I can’t remember what it is. Programmers probably have something to say about it, one way or the other.

Yes, I am not inclined to break columnar alignment. Monos are inherently compromised anyway.

Rainclouds & snowflakes seem far more universal, and thus in the right spirit (if not letter). :)

By “double” I mean exactly twice the width of the other characters.
How would that break vertical alignment?
Please show.

Nick, I see. You are right that columnar alignment would not be broken. The only place this would matter would be be in programmers code where using a doubled glyph would create an opportunity for a mis-count at a glance. 105 glyphs with one of these would look like 106 spaces were being taken. It is unlikely that a programer would use one of these glyphs to program with. But - I think when you use a mono you expect it to play by certain rules. When/if this ever becomes a regular sans Font I will make the adjustments you suggested.

Thanks for the vote Beth!

Why do we not use a rain cloud instead of an umbrella and a cloud with snowflakes or simply a snowflake rather than a snowman?

To play devil’s advocate: a rain cloud would be a little bit harder to distinguish from the existing cloud than an umbrella, and maybe a snowflake would be a little bit harder to distinguish from the existing sun (or an asterisk) than a snowman.