May in Yellowstone National Park is a good month: highs around 58°F, lows around 33°F. Crowds: moderate — #4 busiest of the park's 12 months. Bison calves and bear watching at their best; some passes still shut. The editorial best window here is June & September. You get about 14h 49m of daylight. To finish Mount Washburn (2h 45m) before dark, leave the trailhead by about 5:57 PM.
Month data reviewed · how we check this
| Verdict | Good A solid visit with a caveat — usually crowds or heat. |
|---|---|
| Temps °F | 58° high / 33° low |
| Crowds | moderate · #4 busiest of the park's 12 months |
| What May is like | Bison calves and bear watching at their best; some passes still shut |
| Best window (whole year) | June & September |
| Peak crowds (whole year) | Jul–Aug |
CROWDS: RELATIVE SEASONALITY FROM NPS VISITATION STATISTICS · TEMPS: APPROXIMATE NOAA NORMALS AT MAIN VISITOR ELEVATION — HIGH COUNTRY RUNS 10–20°F COLDER
DAYLIGHT ON MAY 15 · LOCAL PARK TIME (MDT)COMPUTED FROM THE PARK'S OWN COORDINATES FOR THE 15TH — THE MIDDLE OF THE MONTH STANDS FOR IT, AS IT DOES FOR CLIMATE NORMALS. WITHIN A MONTH THESE TIMES SHIFT BY UP TO AN HOUR
LEAVE THE TRAILHEAD BY — TO FINISH BEFORE DARK ON MAY 15WALKING TIMES ESTIMATED FROM EACH TRAIL'S MEASURED DISTANCE AND ELEVATION GAIN — A PLANNING FIGURE, NOT A PACE. ADD YOUR OWN MARGIN FOR PHOTOS, REST AND CROWDS. WATER AT THE COOL-WEATHER RATE, BECAUSE THIS MONTH AVERAGES 58°F. TRAILS WE HAVE NOT MEASURED ARE LEFT OUT RATHER THAN GUESSED
WHAT MAY ASKS OF YOU HEREYellowstone National Park in June — Best window, highs around 68°F, crowds: busy (everything open, long days — wolf watching in lamar valley).
Our verdict for May is "Good". A solid visit with a caveat — usually crowds or heat. Expect highs around 58°F and lows around 33°F, with crowds at the "moderate" level. Temperatures are approximate NOAA normals at the main visitor elevation; crowd levels follow published NPS visitation statistics.
Across the full 12-month review, the best window is June & September, and the peak-crowd months are Jul–Aug. May itself we rate "Good".
June we rate "Best window" against "Good" for May, with highs around 68°F and crowds at the "busy" level.
About 14h 49m on May 15: the sun rises around 5:54 AM and sets around 8:43 PM local park time (MDT). Computed from the park's own coordinates, so it is the light you actually get at the trailhead, not the nearest city's.
Mount Washburn takes about 2h 45m of walking, so on May 15 you would need to leave the trailhead by about 5:57 PM to finish before dark — the sun sets around 8:43 PM local park time (MDT). Walking times are estimated from each trail's measured distance and elevation gain, so treat them as a planning figure and add your own margin for photos, rest and crowds.
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