The Weather Year Round Anywhere on Earth
weatherspark.com
weatherspark.com
My only critique is that without showing precipitation these visualizations could mislead you into thinking two cities have similar climates. I wonder if precipitation could be added to the same plots while remaining just as easily interpretable.
Monetization / expansion roadmap suggestion: an integration with the Google Flights 'explore' feature (price overlay on the world map for flights from a origin airport), if it's feasible. Such an integration would enable us to visualize what weather to expect when traveling to X and what it would cost to get there, simplifying a big part of the initial travel research process.