The Ennis season runs from late May to early October, with the absolute peak in late June and July when the Madison's salmonfly hatch coincides with long days and warm evenings. August and September are quieter, less buggy, and arguably the best months for hopper fishing and for any kind of dry-fly work. Winters are cold (regularly below minus 20 Celsius), the wind can be merciless, and most of the river guides take three months off — but it is a fine time to ski into the Madison Range or watch elk in the valley if you have proper clothing.
The Ennis Rodeo over the Fourth of July weekend is the single biggest event of the year and packs the town for three days.