Actually, the car does not "think". It uses the external temp sensor and when the ambient temp hits 36 degrees F (+2 Celsius) the snowflake will appear to warn the driver that (potentially) wet spots could be turning slick. I will stay all the way through 23 degrees F (about -5 Celsius). Once the temp goes lower than that, it will disappear.When the car thinks that the temp is close enough to freezing that there may be slick road surfaces......usually within a few degrees above.
This is my first Volvo and it isn't mentioned in the manual. I RTFMed several times and searched the PDF yesterday...This isn't new to Volvo's, they've had the "Snowflake" symbol for a long time now.
Mine came on at 31 degrees here in NJ around 6am.
Also not mentioned in the manual is the automatic rear defroster kicking in at startup when the OAT is below about 45F.Odd that this is not in the manual (I could not find it either). I did find this in the
XC90 manual (searching PDF):
When the ambient temperature is between 23° and 36 °F (–5° and +2 °C), a snowflake symbol is shown in the display.
So below 23F it is off.
This time of year we think about the temps falling and that gives a false trigger since ice has
not accumulated. It is the temp rising from below freezing to above freezing (early morning) where
there is still ice on the ground that I think is most important to warn about.