Boulder Film Festival Weather: What January and April Bring

Nov 2, 2026 / Nov 3, 2026 · 8 min read · boulder weather sundance film festival boulder international film festival january weather april weather snow wind colorado weather ·

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Two Festival Seasons: Boulder Weather in Late January and Early April

Boulder's two big film festivals fall in different seasons. The Sundance Film Festival runs Jan. 21-31, 2027, its first edition in Boulder after leaving its longtime home in Park City, Utah, with about 80,000 people expected, mostly Coloradans going to single screenings. The Boulder International Film Festival (BIFF) follows on April 8-11, 2027, four days that log more than 25,000 attendances.

How Cold Is Boulder During Sundance Week?

The two festival months sit about 14 degrees apart in the 1991-2020 normal monthly mean at the NIST station: 34.42°F for January and 48.87°F for April. On the same 1991-2020 NIST basis, the normal January high is 46.76°F and the normal January low is 21.99°F.

The daily normals for the festival's 11 days run a little lower and hardly move: highs of 44-45°F and lows of 19-22°F, from 44°F and 19°F on January 21 to 45°F and 20°F on January 31. Those daily highs sit about 2 to 3 degrees below the 46.76°F monthly normal high, and the daily lows sit up to 3 degrees below the 21.99°F monthly normal low.

The record high inside the window is 74°F on January 22, 1925. The record lows include -18°F on January 21, 1930, and the coldest mark in the window, -20°F on January 26, 1903. January 31 has ranged from 69°F in 1989 to -9°F in 1985. The temperature records go back to 1897, and the station has been at its current NIST site since April 1990.

Whole Januaries swing as well. The monthly record starts in 1897, so its early Januaries predate the station's 1990 move to NIST. In that record, January 1930 averaged 16.4°F, the coldest January mean, and January 1953 averaged 43.5°F, the warmest. The 1991-2020 standard deviation for the January mean is 3.23 degrees. The last three Januaries averaged 30.2°F in 2024, 27.9°F in 2025 and 37.6°F in 2026, nearly 10 degrees apart within three years.

How Much Snow Falls in Late January, and Does It Stay on the Ground?

January's normal snowfall at NIST is 11.76 inches, with a standard deviation of 7.74 inches. That is a wide spread for a monthly total under 12 inches; the month-by-month snow averages and biggest storms put January in the full-year pattern. The last three Januaries show the range: 10.8 inches in 2024, 24.9 inches in 2025 and 10.7 inches in 2026.

Snow also stays on the ground in January. At least 1 inch covered the ground on 41.6 percent of January days in the 1991-2020 normals. Over an 11-day festival, that comes to four or five days with snow underfoot on average.

The largest single-day snow record inside the festival window is 10.4 inches on January 24 (1978). Four of the window's daily snow records were set or tied in 2014 or later: 9.8 inches on January 26 and 5.7 inches on January 27 (both 2014), 7.1 inches on January 21 (2017) and 6.5 inches on January 25 (2025, a record shared with 1996). Snow records start in 1948.

January High Wind in Boulder

Boulder has some of the highest peak winds of any US city. January has had more Boulder-area wind events of 70 mph or more than any other month: 73 events over 30 different years. December is next with 63 events in 29 years. April has 15 events in 8 years. The counts take in foothill and plains reports such as Rocky Flats, Table Mesa and Longmont, as well as the city itself. Inconsistent reporting means events may be missing or recorded speeds may be inaccurate.

On January 16-17, 1982, a gust of 137 mph was measured at NCAR, and 40 percent of all Boulder buildings were damaged. On the evening of January 30, 2018, a date inside the 2027 festival window, gusts reached 80 mph at the NCAR Mesa Lab southwest of Boulder and 97 mph 2 miles south-southeast of Gold Hill.

Strong winds have also driven fires in the Boulder area, including on January 18, 2006, January 7, 2009 and December 30, 2021. The 2006 and 2021 fires were grass fires. The December 2021 fire developed from Marshall, under the wind and drought setup behind the Marshall Fire, and destroyed 1,094 houses plus some commercial structures.

What BIFF Weekend in Early April Usually Feels Like

April is milder, and its monthly temperature swings less. The 1991-2020 normal April high at NIST is 62.64°F and the normal low is 35.10°F. The April mean has a standard deviation of 2.70 degrees, against 3.23 for January. The last three Aprils averaged 50.8°F in 2024, 50.0°F in 2025 and 53.0°F in 2026, all above the 48.87°F normal.

The daily normals for BIFF's four days sit close together: 57°F and 33°F on April 8, 59°F and 33°F on April 9, 59°F and 34°F on April 10, and 58°F and 34°F on April 11.

The daily records for April 8-11 still span 82 degrees. The highs are 83°F on April 8 (1930), 78°F on April 9 (1977 and 2019), 80°F on April 10 (1960) and 84°F on April 11 (2023). The lows are 9°F on April 8 (1973), 8°F on April 9 (1973), 2°F on April 10 (2013) and 9°F on April 11 (1940). Two of those records are recent: the 84°F high from 2023 and the 2°F low from 2013.

Snow and Wind During BIFF

April's normal snowfall is 13.59 inches, more than January's 11.76, with a larger standard deviation of 12.59 inches. April snow melts fast: only 8.7 percent of April days have at least 1 inch on the ground, against 41.6 percent in January. The last three Aprils fell short of the normal, with 9.7 inches in 2024, 9.8 inches in 2025 and 1.7 inches in 2026.

From 1949 to 2014, the last day of measurable snow came at a median of April 25 and an average of April 27. The low decile is April 2, so in about nine years out of ten, measurable snow still fell after that date. The first quartile is April 18, so in about three years out of four, the last snow came a week or more after BIFF's closing day. The earliest last snow was March 22 (1992). The latest was June 7 (1993).

The single-day snow records for the festival dates are all heavier than the 10.4-inch maximum in the Sundance window: 11.5 inches on April 8 (1959), 13.1 inches on April 9 (2013), 11.1 inches on April 10 (1995) and 12.0 inches on April 11 (1953). In 2013, the April 9 snow record and the April 10 record low of 2°F fell on back-to-back days.

From late afternoon on April 6, 2023 to early morning on April 7, numerous gusts reached 70-90 mph, including 89 mph 3 miles south of Boulder. On the morning of April 4, 2022, gusts reached about 75 mph in the foothills and plains. Both storms came within a few days of BIFF's calendar slot.

Daylight, Forecasts and What to Pack for Each Festival

Late January runs on standard time. On January 21 the sun rises at 7:17 am and sets at 5:06 pm, giving 9 hours 49 minutes of daylight. On January 31 it rises at 7:09 am and sets at 5:18 pm, giving 10 hours 9 minutes. Anyone outdoors after sunset, about 5:10 pm, during Sundance is out in fading twilight and then darkness, and the daily normal lows for the window are 19-22°F.

April falls in daylight saving time. With the daylight-saving hour added, April 8 has sunrise at 6:34 am and sunset at 7:31 pm, with 12 hours 57 minutes of daylight. April 11 has sunrise at 6:29 am and sunset at 7:34 pm, with 13 hours 5 minutes. Each BIFF day has roughly three hours more daylight than a Sundance day.

The NWS Forecast Office Denver/Boulder, at 325 Broadway in Boulder, issues the local forecasts and has a Resources for Outdoor Events page. The Sundance schedule is expected in December.

For Sundance, pack for daily normals from about 20°F at night to the mid 40s by day. Bring boots that can handle snow, since about four days in ten have snow on the ground. Add a windproof outer layer, because January has the most documented 70-mph wind events in the Boulder area. Bring gloves and a hat for time outdoors after the 5 pm sunset.

For BIFF, a lighter jacket covers the normal highs near 60°F. Pack a warm layer and waterproof shoes as well: measurable snow still falls after mid-April in most years, and the April 8-11 records include single-day snows of 11 to 13 inches and a low of 2°F.