What does this icon on the iPhone weather app mean?

I see it for Washington DC of this coming Sunday, and Sunday’s forecast for DC is Snow followed by mixed precipitation in the afternoon/evening. So snow turning to mixed snow/rain.

One forecast just says freezing rain for Sunday.

The thermometer means it may or may not freeze.

I’m not seeing in for NJ where it’s unseasonably warm today, but snow is predicted for Sunday; nor do I see it for Denver where it’s very cold. My guess is that it’s a frost/freeze warning, if you live in an area where that does not commonly occur.

Forecast for snow and the temperature is dropping.

Weather