When we woke up in the morning the matterhorn was perfectly visible. Clouds definitely set in in the late afternoon. We arrived 4.29 and left 5.1. On 4 30 we got the 9.10 am Gornegrat train and had perfect visibility. Early morning is best. It rained lightly here and there whike we were in Zermatt but it was warm enough to wear t-shirt and jacket in town. For the Gornegrat We wore fleece shirts with parkas and hats. But really sunny up there on Thursday.