Progreso is the most consistent spot i know in Mexico. I have had a session every time i have gone during many different months of the year. The strongest and steadiest winds can be found from Jan/Feb to May/June, but there is really good wind almost all year round. Most local kiters do not own a kite bigger than 12m, and many have 6-8-10-12 to be perfectly powered for the day.
Many of my friends there wonÂ´t pump up a kite if the wind is not over 15 knots!!! The only thing lacking there is waves, but you get some nice little kickers and with north cold fronts you get a bit more wave action from close period windswell.
Merida is about a 1-1.5 hour flight from Miami, 2 hours from Mexico City by plane, there are direct flights from many cities in the USA and South America and Europe. It is 3-4 hours from Cancun and Playa del Carmen by car. The area is beautiful, with great food, ancient Mayan Ruins (Chichen Itza), mangroves, swamps, cenotes (clear water sinkholes where you can swim/snorkel and even scuba dive) , flamingos and even jaguars in some areas. If you have a car, and know the way, you can be at the beach in 20 min from Merida. There are tons of spots that get the same reliable trade winds, and most of the beach is shallow and sandy, basically no rocks.
The normal winds here are trade winds, very reliable and steady, cross-side shore from the right if you are facing the ocean (North). And the air and water are warm year round, you may need a shorty during the cold fronts that come down about weekly during the winter, but if you are from northern climates you will be fine. The cold fronts come down pretty often during the winter, and can be quite strong, and on-shore. These winds are more gusty, but so strong you can get out from the beach pretty quickly.
Here are some pictures, sequence videos and video of the nationals we had there March '07 with about 25-30 knots:
http://picasaweb.google.com/asantacruz/ ... h17th2007#
http://picasaweb.google.com/asantacruz/ ... lfDay2007#
http://picasaweb.google.com/asantacruz/ ... Night2007#
http://picasaweb.google.com/asantacruz/ ... h19th2007#
http://picasaweb.google.com/asantacruz/ ... rnoon2007#
This video has some shots of Progreso:
Let me know if you want more info, and i can hook you up with local Scuba guide and instructor, kite instructor, kite guide, kiters, etc.