I went to Medellin earlier this year. Liked the place and it does have nice weather.A must visit is Medellin... The days of Escobar are long gone. It's cheap, it has modern amenities, a relatively new subway, good food, great weather and very friendly people. If you like eating a variety of fruits, it's paradise.
There are lovely cities in Mexico with good climate without the traffic, craziness and pollution of CDMX. Queretaro, Puebla, San Miguel de Allende, Huaxaca... Cartel and crime is as usual overblown by the media. Sure it's not as safe as Hong Kong but it's certainly not as bad as it's often portrayed