Sep 2, 2017 - 1:34 PM
Hi Beachgirl, welcome to MySwissAlps!
Yes, your user name says it all :-) If you dress in multiple thinners layers, plus sunglasses, gloves and solid shoes, it will be fine for a regular visit. A scarf would be comfortable too. During the day it will probably be between -10 and +5 °C. If you plan lots of snow activities then you need waterproof clothing, e.g. ski gear.
Everything you need for skiing is for rent in Zermatt. Mid September is not a good time to ski though. Experienced skiers can ski in thin air, high on the glacier, particularly in the morning. For an actual ski experience you'd best come in winter.
Have fun at Klein Matterhorn (Glacier Paradise)!