Many users are likely to find out about the weather with the help of Google products because it can be displayed in many places, from web searches to the assistant to the widget or smart display.
The opinion is divided on the reliability of the forecasts, but at the moment they are probably completely wrong. The Google Assistant sees freezing temperatures and many apps fail to load the weather.
Google is currently having some indexing issues affecting new content and apparently including weather. Both the current weather and the forecast cannot be retrieved and therefore either lists incorrect results or – in most cases – simply an error message.
Because Google probably stores the temperatures internally in degrees Celsius and not degrees Fahrenheit (which is surprising for a US company), the value “0” is probably simply interpreted there as zero degrees. At least this is what the Assistant returns as the current temperature.
It’s hard to say how widespread the problem is. For me personally, everything works as usual. For some users, only their own prediction, which is tied to a previously specified location, is probably affected. Temperatures and forecasts elsewhere should, however, be available. In any case, it is to be expected that Google will quickly get the problem under control.