I've found Weather Spark to be a useful tool for researching ideal climates: https://weatherspark.com/. It has detailed temperature breakouts by time of day and year, wind speed, humidity, rainfall, etc.

One thing I've started to pay a lot more attention to is rainfall. The temperature in Southern California (where I currently live) is certainly pleasant, but that comes with the tradeoff of very limited rainfall, which seems to be having an increasingly negative impact as the years wear on.