Climate Metric

[blksith0]

Imagine you have a big list of cities and wanted to concisely get an idea of what the weather is like over there.
If conciseness and speed wasn't a problem, you could look at a graph like this (below) for each city, but that's not fast.

So what metrics would you need to accurately capture the climate of that area? Less is better, so all I can think of is: average lowest temp, average highest temp.
Any other ideas?

 

[blksith0]

I think average temp along with temp variance would do.