It's gotten down to 17 degrees here yesterday and we are getting no ice warning like we use to. My wife said she got one the other day (four days ago) but none since. No warning light no chime. Yes it has got above 37 and then back down with nothing. Even drove over some black ice!

 

I have had the warning light come on in 40 degree weather this month. Next to the seat belt warning, I really do not think this feature is necessary.

 

Mine came on for the first time about 5 days ago. It hasn't come on since.
I assumed that it either needs to be manually reset, or the temp has to go significantly above 37 deg F. to reset it automatically. To be honest, I've only had the car 2 weeks and hadn't given it much thought, but I do like the feature. It was on my 3 series beemer also.
No worries though, once it's cold enough to freeze water you just have to pay attention until, oh, say April. Hopefully it'll be a milder winter here in New England, and not all of the ice we usually get in Connecticut.
I just put the winter tires and rims on this afternoon, so now I know it will be in the 60's next week,

 

If it's below freezing I don't think you need your Mini to tell you to be careful...

 

Mine comes on every day its below 37 but I do park in a garage that is about 60. I have not noticed one way or the other on the way how from work.

 

I do not have the manual handy, when is the warning light suppose to activate?

 

< 37 deg F. according to my manual.

 

Your Mini was just hoping that you wouldn't notice so it could do some drifting on the curves!

 

The purpose of the warning and snowflake is if you are driving along and the temperature drops down to 37 degrees it warns you that the roads could become slippery. If you get into your car and start it up and it is already at 37 degrees or below BMW assumes that you are smart enough to figure out the roads could be slippery. There is no reset for this.

This is the reason it goes off when leaving a warm garage. The car doesn't know it was in a warm garage it just knows it went from a warm zone to a cold zone.

 

Gee, I wish my ice warning would break...

 

While driving the Cherohala Skyway the other day (near the Dragon) it was 39 at the beginning, got down to 29 at the summit and then back to 39 at the other end, never triggering the ice warning.

 

Call yourself lucky, you didn't get that annoying noise. Sounds like you don't need it either as you are aware of your surroundings.