Last year the festival was 16-21 Feb, so I assume it will be 15-20 feb this year. This website may help out as well. www.visitevinadelmar.cl
You may also want to google realtors (corredores de propiedades) in vina to help with rentals that time of year. A few you might try are Nieny -- www.nieny.cl --- [email protected]. Axtell -- www.axtell.cl -- [email protected]. Silvia Ostornol -- [email protected] -- [email protected]. There are many others, but we had help from these three when finding our apartment. There is no multiple listing here, so you have to go through each realtor separately. Jwatts