The best time to visit Venezuela is December-May, when the weather is at its driest. December and January are especially cool and pleasant. April-September is very warm, and it is usually rainy from May-December. In Merida, the weather is best from October-June. The Orinoco River area can be more humid and a bit warmer, and the mountain areas will generally be at least 10 degrees F/5 C cooler (and much colder at high elevations). No matter when you go, be sure to take a sweater - the evenings are cool most of the year.