Grand Teton Forecast Sunday – Monday 19-20 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.

A couple of stormy and cold days ahead

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, then rain and snow, and a possible thunderstorm overnight.

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

Smoke forecast: Decreasing smoke in the Park on Sunday with no smoke by afternoon. Some smoke moves in Monday morning (this time from Idaho and Montana) but should again clear out by Monday afternoon.

Extended Outlook:

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

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

Saturday: Partly to mostly sunny and warmer. Highs in the low 70’s.

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