Ifr & cloud.... icing question

[Coopere]

Well staring my ifr rating next week, wrote the inrat passed.

But theirs one thing I can't wrap my head around

How do you know when you will develop icing when in cloud?

I understand above 0c temps (+3 and above) you won't develop ice, I also know that temps slightly above 0c can develop ice

I also know that temps below -25c (very cold temps) you won't develop ice

But what about temps from 0c to -25c

I understand gfa forcast icing but is just that a forcast
Pireps are rare up here in Canada from what I see flying daily their isn't a huge number of ga guys flying around compared to in the USA.

I thought I saw somewhere or read somewhere if you see a rainbow / halo in the cloud (from above) their is non frozen moisture in the cloud

Hoping someone can shed some light on this for me
Thanks
Eric

 

[FlyCanadianGuy]

 

[FlyCanadianGuy]

 

[TEG916]

 

[Coopere]

 

[Coopere]

 

[rrc1962]

 

[JimICS2452]

 

[Orest @ CYFD]

 

[GM.]