Grand Junction (CO) Temperature by Month

The average annual maximum temperature in Grand Junction, Colorado, United States of America is 19°C (66°F), with daytime highs ranging from 3°C (37°F) in January to 34°C (93°F) in July. This page covers monthly averages, day-night differences, and how Grand Junction compares to cities worldwide.

In Grand Junction, temperatures differ significantly between summer and winter months. Nighttime lows reflect this range, dropping from 18°C (64°F) in July to -9°C (16°F) in January.

The chart below illustrates the average maximum day and minimum night temperatures in Grand Junction by month:

From around 4 AM to 6 AM temperatures are at their lowest; by 3 PM they've climbed to their daily peak. July, the warmest month, averages 355 hours of sunshine.

The chart below shows the average temperature throughout the year:

Grand Junction's average annual maximum temperature is 19°C (66°F). To put that in context, here's how it compares to a few well-known destinations:

Lisbon, Portugal averages 21°C (70°F) annually, warm summers, mild winters, and rain mainly in the cooler months.

Toronto, Canada averages 13°C (55°F) annually, with cold snowy winters balanced by genuinely warm summers.

Buenos Aires, Argentina averages 23°C (73°F) a year, with hot summers and mild winters, and seasons reversed compared to Europe.

Perth, Australia averages 25°C (77°F) annually, with a classic Mediterranean climate, hot dry summers and mild wet winters.

Temperature alone doesn't tell the whole story, humidity plays a big role in how warm or cold it actually feels. High humidity in summer makes the heat feel more intense, particularly once temperatures climb above 25°C. In winter, the same humidity can make cold air feel sharper than the thermometer suggests.

In the cooler months, when temperatures drop below 10°C, high humidity makes the cold feel more cutting than it would in dry conditions.

In Grand Junction, January is the coolest month, with average highs of 3°C (37°F) and humidity around 68%, considered high. In July, the warmest month, temperatures average 34°C (93°F) with 35% humidity, conditions that feel low. For a full picture, see our humidity page.

Climate temperature data is typically calculated as a 30-year average. This smooths out year-to-year variability and gives a more reliable picture of what a place is actually like, rather than what happened in any single unusual year.

The readings come from a range of sources, land-based weather stations, ocean buoys, ships, and satellites. That data is collected by weather services around the world, then pooled, quality-checked, and averaged to produce the climate records you see here.

Seasonal temperature shifts influence more than just how warm it feels, they also drive changes in rainfall, cloud cover, and wind patterns throughout the year.

Warmer air holds more moisture, which tends to mean heavier or more frequent rain during the warmer months. When temperatures drop in winter, any precipitation that does fall is more likely to come as snow or sleet, though in Grand Junction this rarely lasts long on the ground.

For more on Grand Junction's weather, including monthly rainfall, sunshine hours, and humidity, visit our Grand Junction climate page.