ClimateForecastSeptemberOctober >>

Boulder weather in September (Colorado, United States of America)

Is Boulder a good destination in September, weather-wise? Here’s a detailed forecast of the month’s weather patterns.

Temperatures

The weather in Boulder during September is usually perfect, offering high temperatures and moderate rainfall. Daytime temperatures generally peak at 26°C, but after sunset, they often decrease to around 10°C.

Precipitation

Boulder in September usually receives moderate rainfall, averaging around 67 mm for the month. Historically, approximately 8 days this month are expected to have rain.

Average sunshine

The days are predominantly sunny, with an estimated total of around 270 hours of sunshine. These sun-filled days are perfect for spending time outside. Whether it's playing sports, visiting a park, or going for a bike ride.

If you're inclined towards comfortable temperatures and drier conditions, September is a prime time to visit Boulder. May, June, August and September typically offer the best circumstances. While December tends to showcase less optimal conditions.

For an in-depth look at the yearly conditions, visit our specialized Boulder climate page with graphs.

 

Boulder, monthly averages in September

Min TemperatureMin Temperature 10°C  
Max TemperatureMax Temperature 26°C  
Chance of RainChance of Rain 27%  
PrecipitationPrecipitation 67 mm  
Rainy daysRainy days 8 days  
HumidityHumidity 50% *  
SunshineSunshine 270 hours *  
Percentage SunshinePercentage Sunshine 73% *  
Data from: Denver, the United States of America (45 KM, 28 Miles).

Where to go in the United States of America in September

Find out more about the weather in the United States of America and which places have the best travel conditions in this month.

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Legend perfect weather pleasant tolerable unpleasant poor
Perfect weather is subjective. On this map perfect weather has been defined with temperatures between 20°C and 29°C and not too much precipitation (less than 90 mm a month).

So, what should you wear in this month?

It's going to be warm! Consider airy clothing, t-shirts, and other summer clothes. Shorts for men made of cotton or linen are good options for staying cool.

What To Do

We rated the following activities from 1 (least suitable) to 10 (best) to do.

Swimming
9/10
Cycling
8/10
Walking
8/10
Camping
4/10
Outdoor sports
8/10

Interested in more climate information?

This site provides you with all the information you need about the climate in Boulder.

Our site offers climate and forecast data for every country in the world. Are you going to the United States of America? On this website you can find historical weather averages for many cities in the United States of America. Not sure yet where to go? We now have a tool which recommends destinations that suit your ideal travel conditions. Find out where to go with our weather planner.