Denver weather and climate guide

7-day forecast for Denver

Tonight in Denver, CO brings showers and thunderstorms likely. Across the 8-day outlook, highs average 86°F and lows average 59°F, ranging from 56°F to 90°F. 4 of the 8 days carry at least a 30% chance of precipitation, so keep rain gear handy.

Current conditions

Observed at Broomfield / Jeffco (KBJC) at 5:45 PM MDT.

Altitude changes how weather feels

At 5,280 feet, atmospheric pressure is roughly 83% of sea level. That has several practical consequences that surprise visitors.

Sunlight is stronger. There is less atmosphere overhead to absorb ultraviolet radiation, and UV intensity increases roughly 4 to 5% per thousand feet of elevation. Denver's summer UV index regularly hits 10 or 11, and sunburn happens faster than the temperature suggests it should. Snow adds reflected UV on top of that, which is why spring skiing produces such distinctive burns.

Air holds less heat. Thin, dry air has low heat capacity, so it warms fast in sun and cools fast after sunset. A 40 °F swing between afternoon high and overnight low is unremarkable here. Shade feels dramatically cooler than sun even at the same air temperature — a 60 °F day is shirtsleeves in direct sun and jacket weather in shadow.

Dehydration is faster. Relative humidity often sits under 30%, and respiratory water loss increases at altitude. Visitors who feel unwell on day one in Denver are usually dehydrated rather than experiencing genuine altitude sickness, though real altitude illness becomes a factor in the mountains above 8,000 feet.

Chinook winds and the warm-in-winter effect

Denver's winters are far milder than its latitude and elevation suggest, and chinook winds are a large part of why. When westerly flow crosses the Rockies, air is forced up the western slope, loses its moisture as precipitation, then descends the eastern slope. Descending air compresses and warms — roughly 5.5 °F per thousand feet for dry air.

The result is a dry, warm, often ferocious downslope wind that can raise Denver temperatures 40 °F in a few hours and strip a foot of snow off the ground through direct sublimation. Locals call it a snow eater. It is why January here averages a high of 45 °F while Minneapolis, at lower elevation and similar latitude, averages 24.

Chinooks are also a hazard. Boulder and the foothills communities regularly see 80 to 100 mph downslope gusts, strong enough to overturn trucks on the north-south highways and to drive extreme wildfire behavior. The Marshall Fire of December 2021 — the most destructive fire in Colorado history, destroying over a thousand homes in Boulder County — was a grass fire driven by hurricane-force downslope winds in the middle of winter, on ground with no snow cover.

Hail alley

The corridor from Cheyenne through Denver to Colorado Springs receives more damaging hail than anywhere else in North America. Denver averages three to four hail days per year, concentrated in May and June, and Colorado routinely ranks at or near the top nationally for hail insurance claims.

The reason is a combination of factors. Storms form over the high terrain and move east, the freezing level sits relatively low because of elevation, and the atmosphere is dry below cloud base. Low freezing levels mean hailstones have less warm air to fall through and melt in, so they reach the ground intact and large.

The July 1990 Denver hailstorm remains among the costliest in United States history in inflation-adjusted terms. Hail insurance deductibles here are structured differently than in most states, and roofs on the Front Range are replaced far more often than the national norm. If you are moving here, read the hail provisions of your homeowners policy specifically.

Spring is the snowiest season

This is counterintuitive and important. Denver's single snowiest month is March, and April often out-snows January. The reason is that the biggest snowstorms here require moisture, and the atmosphere is warmer and wetter in spring.

The classic setup is an upslope storm: a low pressure system south or east of the city pulls moist air in from the east, forcing it to rise as it approaches the Front Range. Upslope events produce Denver's heavy, wet, tree-breaking snow, and totals of one to three feet are possible. The March 2003 storm dropped over 30 inches on the city and collapsed roofs.

Midwinter storms often go the other way. When flow is westerly, the mountains wring out the moisture and Denver gets a few dry inches or nothing at all while the ski resorts get buried. This is the source of endless confusion for people who assume mountain snow reports apply to the city.

Summer: hot afternoons, cool nights, daily storms

July averages 90 °F by day and 59 at night — a 31-degree daily range that makes summer here comfortable in a way that Midwest and Southern summers are not. Air conditioning matters less; evenings are genuinely cool.

The daily rhythm in July and August is driven by the North American Monsoon reaching this far north. Moisture arrives from the southwest, thunderstorms build over the mountains in late morning, and they drift onto the plains in the afternoon. Hikers above treeline need to be heading down by noon, because Colorado leads the nation in lightning deaths per capita in some years and the exposure above treeline is total.

Tornadoes do occur, mostly northeast of the city in Weld and Adams counties. They are typically weaker and shorter-lived than Great Plains tornadoes, but Denver International Airport sits in an unusually active corridor sometimes called the Denver Convergence Vorticity Zone.

Weather hazards to know about

• Large hail

  May and June, extending into August

  The single most expensive weather hazard on the Front Range. Low freezing levels let large stones reach the ground without melting.

• Upslope blizzards

  March and April, and any month October through May

  Heavy wet snow with strong wind, capable of one to three feet and closing the interstates and the airport for a day or more.

• High downslope winds

  November through March

  Chinook gusts of 80 to 100 mph in the foothills. A major wildfire driver even in winter, as the Marshall Fire showed.

• Lightning

  June through August

  Afternoon mountain thunderstorms make above-treeline exposure genuinely dangerous. Plan to be off high ground by early afternoon.

• Extreme temperature swings and intense UV

  Year-round

  Forty-degree daily swings are normal and 50-degree drops happen. UV reaches 10 or 11 in summer, amplified by elevation and snow reflection.

What to wear and pack, by season

Spring (March to May)

The most unpredictable season. Pack for both 70 °F sun and a two-foot snowstorm, because both are plausible in the same week.

Summer (June to August)

Warm-weather clothing, a light jacket for evenings, rain shell for afternoon storms, and serious sun protection.

Fall (September to November)

Layers. September is often the year's best month; November can deliver either mild sun or the first real cold snap.

Winter (December to February)

A warm coat and boots, but expect to shed layers in direct sun. Sunglasses matter more here in winter than in most cities.