Normal weather for Mount Rainier National Park in September

It's pleasantly warm in September in Mount Rainier National Park with an average temperature of 20°C. Temperatures this month range from a low of 15°C to a high of 25°C. At night, you can expect temperatures between 7°C and 13°C.

In September, there is an average of 135 mm of precipitation, spread over 15 days. Of the total precipitation, about 0,1 cm falls as snow in September. The wind speed is around 3 Bft, mostly coming from the Southwest.

Mount Rainier National Park in September		New York
Average Temperature	20°C	27°C
High Temp	25°C	31°C
Low Temp	15°C	21°C
Total Precipitation	135 mm	57 mm
Rainy Days	15 days	9 days
Total Snowfall	0,1 cm	0 cm
Snowy Days	1 day	0 days

Start of September

The month of September starts in Mount Rainier National Park with warm temps, averaging around 24°C during the day and nights around 13°C. A few showers might pop up early in the month, but overall, it’ll stay mostly sunny and dry.

With the temperature difference between day and night, it’s smart to wear layers. A T-shirt, light pants or skirt, and a light jacket are great for the day. In the evening and morning, choose a light jacket, sweater or hoodie, and long pants.

Mid September

By mid-September, daytime temps drop to around 20°C, with nights around 10°C. During this part of the month, you might see regular precipitation, but there will also be some sunny days.

Since it cools down at night, it’s a good idea to wear layers. During the day, a shirt, maybe a light sweater, and thin pants will do. In the evening and morning, go for a warm jacket, sweater or hoodie, and long pants.

End of September

By the end of September, the average daytime temperature in Mount Rainier National Park is around 18°C, while nighttime temps are about 9°C. Expect regular precipitation, but if you’re lucky, you’ll also get some dry and sunny days.

Because temperatures drop in the evening, wearing layers is recommended. During the day, a shirt, maybe a light sweater, and thin pants will do. In the evening and morning, go for a warm jacket, sweater or hoodie, and long pants.

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UV index

The UV index is a maximum of 5 this month. That's a moderate value on the intensity scale of 1 to 11. Unprotected skin can burn in about 30 minutes.

Is September a good time to visit Mount Rainier National Park?

Looking for sun? September isn’t a good month to be in Mount Rainier National Park. The temperature is nice, but there’s too much chance of rain.

Temperature records for Mount Rainier National Park in September

Check out the climate of Mount Rainier National Park for all months and discover the best travel time

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Daily Temperature in September in Mount Rainier National Park

This chart shows the average daily high and low temperatures in September for Mount Rainier National Park, in degrees Celsius. The red line represents the highs, and the blue line shows the lows. The days of the month are displayed at the bottom of the chart. The data, based on historical observations, provide the average temperatures for this month.

Daily Precipitation in September in Mount Rainier National Park

The chart below shows the average daily precipitation in September for Mount Rainier National Park, measured in millimeters over the past few years. Precipitation is always measured as water, even if it’s snow or hail. The days of the month are listed at the bottom of the chart.

A low average precipitation means that the chance of rain on that day is usually small, while a higher average suggests that it rained more often. But remember, it’s just an average, and every day can be different. Based on historical weather data for September, you can expect about 15 days of precipitation in Mount Rainier National Park.

Daily Precipitation in September in Mount Rainier National Park

Daily Snowfall in September in Mount Rainier National Park

This chart shows the average daily snowfall in September in Mount Rainier National Park, measured in centimeters. The bottom of the chart shows the days of the month. The data is based on historical measurements and gives an idea of the average snowfall in September.

Daily UV Index in September in Mount Rainier National Park

This chart shows the average daily UV index in September in Mount Rainier National Park, with the UV index ranging from 0 to a maximum of 11. The bottom of the chart shows the days of the month. Based on historical data, this chart provides an idea of the daily UV radiation levels you can expect.

Temperature in September in Mount Rainier National Park Over the Years

This chart shows the average temperature in September in Mount Rainier National Park, measured in degrees Celsius, over the past few years.

Total Precipitation in September in Mount Rainier National Park Over the Years

This chart shows the average precipitation in September in Mount Rainier National Park, measured in millimeters over the past years. Precipitation is always measured as water, whether it’s snow or hail.

Snowfall in September in Mount Rainier National Park per year

This chart shows the average snowfall in September in Mount Rainier National Park, measured in centimeters, over the past few years.

Snowfall in September in Mount Rainier National Park over the past years

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Daily Climate in September for Mount Rainier National Park

Click on any day in September to get detailed info about the usual weather on that day in Mount Rainier National Park. Check out the historical temperatures and precipitation over the past 10 years on this day.

Average Weather in Mount Rainier National Park by Month

Click on a month below to see detailed weather info for Mount Rainier National Park. Based on historical weather data, you can see the average temperature, precipitation, wind, and UV index for each day of the month.