Why is one US state, California, more populous than Canada, especially since Canada is so much bigger in land mass than California?

California is more populous than Canada, because it is an attractive place to live. The weather in California is virtually snow free, the ocean is temperate in the summer and even the very hot valley weather is generally a dry heat, which is easier to escape and mitigate than humid heat.

WROnG, TC,. The sierras get More Snow than anyplace in  US.

The ocean is Ice Cold for much of the coast for most of the year. Stinson Beach, icey even in summer. No one swims up there, rare to even surf.. Gets Tolerable about Santa Barbara and points south in   August. Then cold, again, in the winter.The Central valley is a Humid heat. Dry is So. AZ. Even then, humid at night with monsoons.

Much of Canada hasn't been opened up and is really not habitable - and then there's the availability of jobs.   To live and survive, people in general, need jobs!!

Because of all them illegal aliens. 

Why does India, which has a total area less than half of the US, have almost 4 times the population of the US?