The Rapel Valley is comprised of two sub-regions, the Cachapoal and Colchagua Valleys. Two rivers, Cachapoal and Colchagua’s Tinguiririca converge to form the Rapel River, which continues west to the Pacific Ocean. The lower areas have a maritime climate, with a strong cooling effect from coastal breezes. The effects of the Andes is felt further inland, where the long growing season features bright blue skies and hot, dry afternoons that are cooled by breezes blowing down from the mountains. The region's climate is best suited to Cabernet Sauvignon, Merlot, Carménère, and more recently to Syrah as well. Chardonnay also does well in some of the cooler microclimates.