The best time to visit is May-September. Summer days can be hot, but take a sweater for evenings. Winters are wet, cold, dreary and not a great time to visit unless you're interested in skiing (December-April). In May and June, the fields are overrun by wildflowers: poppies, cornflowers and daisies. October is also a good time to go, because the weather is mild and there are no crowds.