Early autumn · Weather & things to do
Yellowstone National Park in September
Yellowstone National Park cools off: highs slip to 61°F (16°C), from 71°F in August, with lows of 35°F (1°C) and about 2.0 in (52 mm) of rain.
At 86/100 for comfort (3rd of 12), it's one of the best months to visit.
- Avg high
- 61°F (16°C)
- Avg low
- 35°F (1°C)
- Rain
- 2.0 in (52 mm)
- Humidity
- 58%
- Cloud cover
- 48%
- Daylight
- ~12 h 17 min
- Comfort score
- 86/100 · Great
What September feels like
Days are mild at around 61°F (16°C): comfortable for walking all day, with a layer for the evening.
There's a big swing between day and night, about 15°C (26°F), so mornings and evenings feel much cooler than the afternoon.
Rain is moderate at about 2.0 in (52 mm) for the month.
Plan around September
September is one of Yellowstone National Park's best months on the climate data.
- Last of the best-scoring months: by October, the score drops to 50/100.
- Comfort slips from 96/100 in August to 86/100.
- September sits inside the Jun – Sep window our Glacier to Yellowstone route recommends.
What to pack for September
- A warm layer for eveningslows near 35°F
- Comfortable walking shoesmost places below are best reached on foot or with short walks
What to do in Yellowstone National Park in September
September is good outdoor weather here, so these picks lean toward the open air.
Artist Point
Classic viewpoint of the Lower Falls and the yellow walls of the Grand Canyon of the Yellowstone.
Why now September scores 86/100 for comfort, good conditions for being outside.
Old Faithful
Yellowstone's best-known geyser, erupting roughly every 60–110 minutes.
Why now Highs near 61°F and 2.0 in of monthly rain make this an easy outdoor pick.
Lamar Valley
Broad northern valley known as the best wolf-watching area in the park.
Why now One to do outside while the weather is on your side.
Hayden Valley
Open valley along the Yellowstone River with bison herds and frequent wolf and bear sightings.
Bear Pit Lounge
Small bar off the Old Faithful Inn dining room with historic etched-glass panels.
Nearby in September
- Yellowstone in September~13 mi · highs 60°F, 2.0 in rain · similar daytime temperatures, about as wet
- Grand Teton National Park in September~44 mi · highs 65°F, 2.0 in rain · 3°C (5°F) warmer by day, about as wet
- Jackson in September~67 mi · highs 70°F, 1.8 in rain · 5°C (9°F) warmer by day, about as wet
- Salt Lake City in September~262 mi · highs 79°F, 1.5 in rain · 10°C (19°F) warmer by day, about as wet
NASA POWER 2001–2025 monthly averages on a ~50 km grid. Comfort scores weigh temperature, rain, humidity and cloud: see how we score each month. Check a forecast before you go.
Yellowstone National Park in September: quick answers
Is September a good time to visit Yellowstone National Park?
Yes. On the climate data it's one of the best months, scoring 86/100. Expect highs of 61°F (16°C) and 2.0 in (52 mm) of rain. September is inside the Jun – Sep window our Glacier to Yellowstone route recommends.
How cold is Yellowstone National Park in September?
Average highs are 61°F (16°C) and average lows 35°F (1°C), making it the 4th-warmest month by daytime highs.
Does it rain a lot in Yellowstone National Park in September?
Not much: about 2.0 in (52 mm) of rain falls across September on average, the 3rd-driest month of the year. The annual total is about 32.8 in (834 mm).
What should I pack for Yellowstone National Park in September?
Bring a warm layer for evenings (lows near 35°F) and comfortable walking shoes (most places below are best reached on foot or with short walks).
More on Yellowstone National Park
Routes in season in September
- Glacier to Yellowstone Jun – Sep
Planning Yellowstone National Park in September?
Share this September plan with your group, poll everyone on dates and keep the packing list in one place.