Grand Teton Forecast Saturday – Sunday 18-19 September

  • Short-term forecast, emphasizing weather parameters most important to visitors in the Jenny Lake / String Lake / Leigh Lake region
  • Animations of expected weather radar updated daily.
    • Other weather parameters (snow, wind, etc.) added when they may be significant.
    • For orientation, animation maps show Wyoming and a small portion of the surrounding states.
  • Temperature graphic is for the Airport. Subtract a couple of degrees for String Lake and 3-5 degrees if a visitor asks about Colter Bay.
  • The wind gusts forecasts are usually (in the summer) a reasonable forecast for average sustained wind speeds at 9,000 – 11,000 feet for backcountry hikers.
  • For those with access to Grand Teton Park Radios: Channel 16 is NOAA Weather Radio
  • Click here for access to the NOAA smoke-forecasting site.
  • Click here for an animation of smoke concentration over the northwest U.S. for the next two days.

Hazardous conditions (high winds) on Leigh Lake Saturday afternoon and Sunday midday; then sharply colder with valley rain and mountain snow Sunday p.m.

Saturday: Variable cloudiness. Slight chance of afternoon showers and thunderstorms, although most activity will remain south of the Park. Windy in the afternoon with gusts 32-42 mph. The northern and eastern ends of Leigh Lake will become hazardous to paddlers. Highs in the low 70’s.

Sunday: Mostly cloudy. A steady rain develops in the afternoon. Snow levels start at 9000 feet but fall to 6500-7000 feet by morning. Windy midday before the cold front with gusts 30-38 mph. Colder, with highs in the mid-50’s but falling temperatures in the afternoon. Rain, snow, and a possible thunderstorm overnight.

Smoke forecast: Decreasing smoke in the Park on Saturday. By Sunday midday Grand Teton should be basically clear of wildfire smoke.

Extended Outlook:

Monday: Mostly cloudy with rain and snow ending in the morning, giving way to occasional rain showers in the valley and snow showers in the mountains. Some roads may be icy Monday morning. High temperatures around 50 deg.

Tuesday: Partly to mostly sunny. Expect a hard freeze by Tuesday morning with lows in the low to mid 20’s. Highs in the lower 60’s.

Wednesday – Friday: Partly to mostly sunny and milder. Highs in the mid to upper 60’s.

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