I’m not getting any VSI or ASI effects where it is most likely at -1 to -2 OAT in rain in the M20, 414 or the stock 172. I have all anti-icing and pito heat off. I’ve been trying with the “Rain” and “Storm” presets. I tried a few different humidity settings and that didn’t do anything.
Icing is definitely enabled in my settings with no assists enabled.
I’d be really interested to see some weather settings that can produce it. Especially wing ice. I’ve never seen that in sim without using the dev menu.