It says in the linked article that they only have support for 9 cities so far, and they list them as:
Spokane, WA
Syracuse, NY
South Bend, IN
Bellingham, WA
Morgantown, WV
Cincinnati, OH
St Paul, MN
Rochester, NY
New York City, NY
It also says that they are working on improving the data pipeline so that they can reduce the amount of time it takes to add new cities to their dataset and visualization.
Spokane, WA
Syracuse, NY
South Bend, IN
Bellingham, WA
Morgantown, WV
Cincinnati, OH
St Paul, MN
Rochester, NY
New York City, NY
It also says that they are working on improving the data pipeline so that they can reduce the amount of time it takes to add new cities to their dataset and visualization.