Jasper National Park in September

July and August deliver peak hiking weather with daytime temps around 20°C, but also peak crowds and $300+ hotel rates. June brings wildflowers and muddy trails – it's a gamble. September is the sweet spot: golden aspens, elk bugling season, and shoulder-season prices. You might catch snow above treeline, but the light is magical. Winter transforms Jasper into a frozen wonderland perfect for ice walks and northern lights, though many mountain roads close. The Icefields Parkway stays open but requires winter tires. Spring (April-May) is mud season – locals call it 'fifth season' for good reason. Most mountain trails remain snow-covered until late June.