Mount Rainier National Park Weather in September

Mount Rainier National Park in September sees low temperatures, with highs around 8°C (46°F) and overnight lows of -3°C (27°F). Snow/rainfall is fairly high at around 122 mm (4.8 in) on average, so pack waterproofs just in case.

Rainfall in Mount Rainier National Park in September

This month experiences about 12 days of snow/rain according to historical data, averaging 122 mm (4.8 in). Rainfall intensity is on the higher side this month. Expect more substantial showers rather than light, passing rain.

Temperature in Mount Rainier National Park in September

In September, Mount Rainier National Park sees low temperatures, with highs of 8°C (46°F). Nights drop to around -3°C (27°F). September is part of the summer season. The days stay cool from start to finish. Layering up well will make outdoor time much more comfortable. Nights are well below freezing at -3°C (27°F). An extra blanket is a good idea if you feel the cold, especially in older or less well-heated accommodation.

Sunshine in Mount Rainier National Park in September

Enjoy a sunny month with about 209 hours of sunshine, making it one of the brighter months of the year despite the cool conditions.

If you prefer dry days with pleasant temperatures, September may not be the ideal month to visit Mount Rainier National Park. Our weather planner can help you explore destinations with more pleasant weather conditions.