Aug 6, 2015 - 6:46 AM
Have you actually planned an overnight stay in Zermatt? In that case the alternative shouldn't be too far away I guess, as you don't want to spend too much time on traveling. You will have to accept some traveling time though, because you'll have to get out of the valley first. If weather in Zermatt is bad, you do have a change of better circumstances down in the Rhone valley, especially in the western part of it. Consider towns like Brig, Sion and Martigny, or even Montreux along Lake Geneva. They're very different from Zermatt though, being larger towns and not mountain resorts. Another beautiful mountain resort is Saas-Fee, but if weather in Zermatt is bad, it most probably will be in Saas-Fee too.
Do pay close attention to weather forecasts and check local circumstances, as these may vary significantly.