With regard to Mexicans and other Latin Americans living in cold weather climates, keep in mind that Chicago and Northern Indiana have had a substantial Mexican-American community for decades, as has Denver. New York City and environs have had a large Puerto Rican and Caribbean population for a long time as well. OTOH, there was a large settlement of Germans and other Central Europeans in Central and South Texas, including the Hill Country, in the 1800s. Most of their white neighbors were from the Southeastern states, whose forbears came from the British Isles in colonial times.
If the jobs are there, people will migrate, irrespective of the climate of the land of their origins.