Grand Teton Forecast Friday – Saturday 17-18 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.

Windy afternoons, with elevated fire danger the next few days. Big changes coming early next week.

Friday: Partly to mostly sunny. Very breezy in the afternoon with winds gusting 25-30 mph. Highs in mid 70’s.

Saturday: Variable cloudiness. Slight chance of showers around midday, then better chance of showers and thunderstorms in the afternoon. Windy in the afternoon with gusts 30-35 mph. Highs in the low 70’s.

Smoke forecast: Increasing smoke Friday morning, becoming moderate by afternoon. Decreasing smoke on Saturday. By Saturday evening there will be very little, if any, wildfire smoke in the Park. There will be more day to day variability in the smoke as weather patterns become more active. Some rain and snow to our north and west early next week will help too.

Extended Outlook:

Sunday: Mostly cloudy. Some showers developing midday, then becoming a steadier rain in the afternoon. Highs in the mid-60’s but falling temperatures in the afternoon. Rain and a possible thunderstorm overnight. Snow levels falling to 6500 – 7000 feet by morning.

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. 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 around 60 deg.

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

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