I often hear americans (even scientists) say that they prefer the Fahrenheit scale for weather forecasts, but I believe the perceived higher accuracy is an illusion. Forecasts aren’t that accurate for any given micro climate.

For example, I don’t care if my weather forecast says 26°C or 28°C, I know it’s “short sleeves” weather and when I look at a few graphs at the end of the day, it’s been 25.6°C two meters above ground 100 meters south of me and 27.3°C in the garden, but only for 5 minutes etc.

The organizers will inform the city that a critical mass protest is taking place, the city will inform the police and they will cordon off the route. If there are enough people talking part in the protest, the public order authorities will have no other choice - thus the name critical mass. The right to protest takes precedence over the right to drive this specific route.