Thornton (CO) Weather & Climate: Best Time to Visit
Average temperatures, rainfall, sunshine and the best time to visit Thornton.
Climate overview of Thornton
Temperatures in Thornton, Colorado, United States of America, vary greatly throughout the year. July is the hottest month at 32°C (90°F), while December is the coldest at 7°C (45°F).
The city tends toward dry conditions, with around 424 mm (17 in) of rain/snowfall per year. It does, however, have a distinct dry season from October to March. July is the sunniest month, averaging 10.8 hours of sunshine per day.
Thornton Weather by Month
Pick a month to see the average temperature, rainfall and sunshine in Thornton — and find the best time to visit.
Monthly Temperature in Thornton
The climate in Thornton is known for significant temperature differences throughout the year, making the weather dynamic. Typically, average maximum daytime temperatures range from a very warm 32°C (90°F) in July to a chilly 7°C (45°F) in the coolest month, December.
Nights vary from 15°C (59°F) in July to around -8°C (18°F) during the colder months.
Check out our detailed temperature page for more information.
Temperature ranges by month
Rainfall in Thornton
Thornton maintains relatively dry conditions year-round, recording average annual precipitation of 424 mm (17 in). The climate in Thornton shows significant variation throughout the year. Expect moderate rainfall in May, the wettest month, with an average of 72 mm (2.8 in) of precipitation over 12 rainy days.
In contrast, the driest month January offers drier and sunnier days, with around 12 mm (0.5 in) of snow/rainfall over 4 snowy/rainy days. For more details, please visit our Thornton Precipitation page.
The mean monthly precipitation over the year, including rain, hail, and snow
The average number of days each month with precipitation
Sunshine Hours in Thornton
For those who appreciate different seasons, Thornton serves as an ideal destination. Expect longer, more sun-filled days in July with an average of 10.8 hours of sunshine daily, and embrace the darker days in November, offering only 6.5 hours of daily sunlight.
Visit our detailed sunshine hours page for more information.
Monthly hours of sunshine
Daily hours of sunshine
Daily percentage of sunshine
Humidity in Thornton by Month
The relative humidity is moderate throughout the year in Thornton.
The city experiences its highest humidity in December, reaching 56%. In July, the humidity drops to its lowest level at 46%. What does this mean? Read our detailed page on humidity levels for further details.
Relative humidity over the year
Wind Speed in Thornton
The mean wind speed varies between 4 m/s (8 knots) and 5 m/s (10 knots) throughout the year. It is lowest in January, February, May, June, July, August, September, October, November and December and highest during March and April. What does this mean?
The mean monthly wind speed over the year (meters per second)
Best Time to Visit Thornton
Frequently asked questions about the climate in Thornton
What is the best time to visit Thornton?
May and September typically offer the most optimal weather in Thornton. In contrast, January, February and December tend to have less optimal conditions. Thornton has a distinct dry season from October to March.
What temperatures can I expect in Thornton?
Daytime highs range from 7°C (45°F) in December to 32°C (90°F) in July. Nighttime lows range from -8°C (18°F) to 15°C (59°F). Temperatures vary considerably through the year.
How much rain does Thornton get?
Annual rainfall is around 424 mm (17 in). May is the wettest month with 72 mm (2.8 in), while January is the driest with 12 mm (0.5 in).
How sunny is Thornton?
Thornton receives around 3,102 hours of sunshine per year. July is the sunniest month with 323 hours, while November is the cloudiest with just 195 hours. Overall, Thornton enjoys abundant sunshine.
Thornton 3-Day Forecast
Thornton (CO) 3-Day Forecast
Thornton on the map
Thornton is highlighted — select any city to see its climate.
Popular this month
Where to go in July — average daytime high across popular destinations.
Bucket list
Need travel inspiration? Check out our bucket list articles and be inspired.
Yosemite National Park is definitely worth a visit
Vast forests, blue lakes, towering sequoias, and majestic waterfalls hint at the beauty of Yosemite National Park—a true natural masterpiece.
The 10 most alternative cities in the United States
Discover the top 10 fun and alternative U.S. cities rich in art, culture, and adventure. From Portland's hippy charm to Sedona's stunning landscapes.
Sedona: Explore Majestic Red Rock Landscapes
A picturesque artists' town surrounded by red rocks and known for its spirituality, vortex energy, and stunning hikes like Cathedral Rock.
10 most idyllic villages to visit in the United States
Discover 10 idyllic villages in the USA, from California to Vermont. Explore their unique charm, rich history, stunning nature, and vibrant arts scenes.