You should not need much of a wrap this time of the year, just something light if you are on the beach or high in the hills at night. Now January & February it can be chilly. One year (about 15 years ago) it was so cold that you needed a wool serape to lay on the beach. Last year in january I did not heed my wifes advise to take my jacket as she dropped me off at the airport as I was traveling mexico south of PV
by bus & wish to go light as possible. Thank goodness Gloria at Los Cuatro Vientos Hotel keeps a stock of wraps for guests to use. My trip traveling south I froze until I reached Manzanillo!