One word: LAYERS! The days in September are typically sunny and warm – the Ranch is 5,280 feet above sea level – and the evenings cool. Then weekend will be casual and festive attire. Be sure to pack a sun hat and sunscreen as well. If you are planning to horseback ride, bring non-lugged boots (in other words NOT HIKING boots).
Check out the "What To Bring" list here - http://www.hfbar.com/what-to-bring.html
Festive and comfortable. Western-wear is welcome! We will be exchanging our vows in a field, so keep that in mind when selecting shoes.