Northglenn, Colorado climate: Normal weather by month, frost dates and records
Northglenn's normal year runs from 19°F December nights to 91°F July afternoons, with 14.5 inches of precipitation and 45 inches of snow a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 11.3°C, December lows of −7°C, July highs of 33°C, 369 mm of precipitation a year.
- NOAA stationNorthglenn
- Station IDUSC00055984
- Location39.90°N 105.01°W
- Elevation5,407 ft (1,648 m)
- From the center2 miles
- Population38,287
On October 23, the normal high in Northglenn is 64°F and the normal low 34°F, and the chance of measurable rain or snow is 16%.
Normals describe a typical year at the station, not a forecast. The National Weather Service forecast for Northglenn.
- Jan 48° 19°
- Feb 50° 20°
- Mar 58° 28°
- Apr 64° 35°
- May 72° 44°
- Jun 85° 53°
- Jul 91° 59°
- Aug 89° 57°
- Sep 82° 49°
- Oct 67° 37°
- Nov 56° 27°
- Dec 48° 19°
Each month: normal high (large) and low, °F. Fill: the month's normal mean, colder blue to hotter red.
What is the weather like in Northglenn each month?
July is the warmest month, with normal highs of 91°F; December the coldest, with normal lows of 19°F. The most precipitation falls in May (2.35 in), the least in January (0.45 in).
| Month | High | Low | Mean | Precip. | Snow | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|---|
| January | 48°F | 19°F | 33.5°F | 0.45 | 6.0 | 4 | <1 | 29 | 9 h 40 min |
| February | 50°F | 20°F | 34.9°F | 0.54 | 7.6 | 5 | <1 | 26 | 10 h 40 min |
| March | 58°F | 28°F | 43.0°F | 1.21 | 8.2 | 6 | <1 | 22 | 11 h 50 min |
| April | 64°F | 35°F | 49.5°F | 1.94 | 6.5 | 8 | <1 | 11 | 13 h 10 min |
| May | 72°F | 44°F | 58.4°F | 2.35 | 1.2 | 10 | 2 | 2 | 14 h 20 min |
| June | 85°F | 53°F | 69.4°F | 1.50 | 0.0 | 7 | 10 | <1 | 15 h |
| July | 91°F | 59°F | 75.0°F | 1.73 | 0.0 | 7 | 19 | <1 | 14 h 50 min |
| August | 89°F | 57°F | 73.1°F | 1.32 | 0.0 | 8 | 16 | <1 | 13 h 50 min |
| September | 82°F | 49°F | 65.2°F | 1.19 | 0.1 | 6 | 6 | 1 | 12 h 30 min |
| October | 67°F | 37°F | 52.0°F | 1.07 | 2.4 | 5 | <1 | 8 | 11 h 10 min |
| November | 56°F | 27°F | 41.3°F | 0.73 | 6.9 | 5 | <1 | 22 | 10 h |
| December | 48°F | 19°F | 33.3°F | 0.48 | 5.9 | 4 | <1 | 29 | 9 h 20 min |
| Year (annual) | 67°F | 37°F | 52.4°F | 14.51 | 44.8 | 73 | 53 | 149 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. | Snow |
|---|---|---|---|---|---|
| January | 9°C | −7°C | 0.8°C | 11 mm | 15 cm |
| February | 10°C | −6°C | 1.6°C | 14 mm | 19 cm |
| March | 14°C | −2°C | 6.1°C | 31 mm | 21 cm |
| April | 18°C | 2°C | 9.7°C | 49 mm | 17 cm |
| May | 22°C | 7°C | 14.7°C | 60 mm | 3 cm |
| June | 30°C | 12°C | 20.8°C | 38 mm | 0 cm |
| July | 33°C | 15°C | 23.9°C | 44 mm | 0 cm |
| August | 32°C | 14°C | 22.8°C | 34 mm | 0 cm |
| September | 28°C | 9°C | 18.4°C | 30 mm | 0 cm |
| October | 20°C | 3°C | 11.1°C | 27 mm | 6 cm |
| November | 13°C | −3°C | 5.2°C | 19 mm | 18 cm |
| December | 9°C | −7°C | 0.7°C | 12 mm | 15 cm |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00055984; annual normals. Wet days: 0.01 inch or more; 90°F days and freezing nights: NOAA's day counts. Daylight: sunrise to sunset on the 15th, computed from the latitude.
When is the best weather to visit Northglenn?
Normal highs sit between 65°F and 85°F in May, September and October. Of those, October has the fewest days with rain (5).
That is a measurement, not a recommendation: it counts the months whose normal afternoon high sits between 65°F and 85°F, where a light layer is enough by day.
Source: NOAA NCEI 1991-2020 monthly normals, station USC00055984.
When is the last frost in Northglenn?
In Northglenn, the last spring frost (32°F) comes after May 2 in half of years and after May 14 in one year in ten; the first autumn frost comes before October 11 in half of years and before September 26 in one year in ten.
Frost-free in half of yearsFrost in 1 to 9 years out of 10Frost most years
- Last spring frost, half of years after
- May 21 year in 10 after May 14; 9 in 10 after April 18
- First autumn frost, half of years before
- October 111 year in 10 before September 26; 9 in 10 before October 24
NOAA puts the median frost-free season at 160 days, and the season without a hard freeze (28°F) at 182 days.
A hard freeze (28°F) comes after April 20 in half of springs and before October 21 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts Northglenn in zone 6a across its 3 ZIP code areas (6a in 80233, the largest). By the map's own method, the average of each year's coldest night over 1991-2020, Northglenn's NOAA station is in zone 6a: the coldest night of a typical year reaches −7°F (28 complete years).
Frost dates for every NOAA station in Colorado · Frost dates by ZIP code
Source: NOAA NCEI 1991-2020 annual normals (frost probabilities), station USC00055984; USDA 2023 Plant Hardiness Zone Map, ZIP listings: PRISM Group, Oregon State University, https://prism.oregonstate.edu, accessed October 8, 2026; the station zone: ACIS daily lows, 1991-2020. A 10% date means one year in ten has a frost after it in spring or before it in autumn.
What hardiness zone is each Northglenn ZIP code in?
The USDA's 2023 map gives each ZIP code area one zone. Northglenn's 3 ZIP code areas are all in zone 6a. Each ZIP's frost dates are in the frost tool.
Source: USDA 2023 Plant Hardiness Zone Map, ZIP listings: PRISM Group, Oregon State University, https://prism.oregonstate.edu, accessed October 8, 2026; ZIP areas in the place: Census Bureau 2020 ZCTA-to-place relationship file. A ZIP area counts when at least a tenth of its land (and 0.5 km²) lies in the place.
How hot and how cold does it get in Northglenn?
In a normal year in Northglenn, 53 days a year reach 90°F (6 of them 100°F or more), 149 nights fall to 32°F or colder and 73 days bring measurable precipitation.
- Days at 90°F or more
- 53a normal year
- Days at 100°F or more
- 6a normal year
- Nights at 32°F or colder
- 149a normal year
- Days that stay below freezing
- 17high of 32°F or less
- Days with 0.01 inch of precipitation
- 73a normal year
- Days with 1 inch of snow or more
- 16a normal year
The highest temperature in this station's record (since 1984) is 110°F, on August 2, 2008; the lowest is −24°F, on December 22, 1990.
The wettest calendar year on that record is 2023, with 19.82 in; the snowiest season is 2015–16, with 79.5 inches.
Source: NOAA NCEI 1991-2020 annual normals, station USC00055984; records: ACIS (NOAA Regional Climate Centers), station USC00055984. Records use complete months only; a month missing more than three days is left out.
How sunny is Northglenn?
Over a year 77% of the sunlight that would reach the ground under clear skies gets through the clouds in the area around Northglenn, 4.7 kWh per square metre a day. February is the sunniest month (82%) and May the cloudiest (71%).
| Month | Share of clear-sky sunshine | Sunshine, kWh/m² a day |
|---|---|---|
| January | 81% | 2.7 |
| February | 82% | 3.8 |
| March | 79% | 4.9 |
| April | 73% | 5.6 |
| May | 71% | 6.2 |
| June | 78% | 7.0 |
| July | 75% | 6.4 |
| August | 75% | 5.8 |
| September | 81% | 5.2 |
| October | 80% | 3.9 |
| November | 79% | 2.8 |
| December | 79% | 2.4 |
Source: NASA POWER solar climatology, 2001-2020 (CERES SYN1deg). Satellite-based, for the 1-degree cell (about 100 km across) around the station, so it describes the area rather than the airport.
How much heating and cooling does Northglenn need?
A normal year in Northglenn brings 5,449 heating degree days, 1% more than the median U.S. place (5,373), and 879 cooling degree days, 3% fewer than the median (908). Seven months need 300 or more heating degree days, a monthly mean of about 55°F or colder. For gardens and crops, NOAA counts 3,168 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 977 | 0 |
| February | 841 | 0 |
| March | 681 | 0 |
| April | 467 | 2 |
| May | 237 | 31 |
| June | 39 | 170 |
| July | 5 | 315 |
| August | 8 | 258 |
| September | 93 | 99 |
| October | 408 | 5 |
| November | 711 | 0 |
| December | 983 | 0 |
| Year (annual) | 5,449 | 879 |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00055984. A degree day is one degree of a day's mean temperature below 65°F (heating) or above it (cooling); utilities use them to estimate energy use.
Has Northglenn been warmer than normal lately?
2024 averaged 54.0°F, 1.6°F above the 1991-2020 normal of 52.4°F. 1 of the 3 complete years since 2022 ran warmer than the normal.
| Year | Mean | Against normal | Precip. | Snow |
|---|---|---|---|---|
| 2022 | 52.3°F | −0.1°F | 14.93 | 64.7 |
| 2023 | 51.5°F | −0.9°F | 19.82 | 35.6 |
| 2024 | 54.0°F | +1.6°F | 15.81 | 53.8 |
Source: observed years: ACIS, station USC00055984. A year counts only with all twelve months complete.
How does Northglenn's climate compare?
Northglenn is warmer than 109 of the other 124 places with their own NOAA record in Colorado, and wetter than 46. Across the 7,247 U.S. stations with normals, its annual mean of 52.4°F is warmer than 51%.
In the Köppen classification computed from these normals, Northglenn is Cfa: temperate, no dry season, hot summer. What the classes mean.
Places with the most similar year elsewhere
Measured month by month on the normal high, low and precipitation, among places of 20,000 or more people in other states:
Source: NOAA NCEI 1991-2020 normals for every station PlainClimate covers. Similarity: the root-mean-square difference of the 36 monthly figures, precipitation weighted so an inch counts like 6°F.
Which places near Northglenn share this climate record?
10 places have no NOAA station with 1991-2020 normals of their own, and this station is the nearest full record. A place's own climate can differ from these figures, by several degrees where it sits much higher or lower than the station, nearer the coast, or inside a large city's heat; for the larger places the next nearest records are named with their yearly mean, so the spread around them is visible, and places of 50,000 or more have their own page with NOAA's gridded normals.
- Thornton, COalso near: Brighton (6 mi, 50.6°F a year); Denver Water Dept (14 mi, 53.3°F a year)146,689 people · 4 mi E
- Westminster, COalso near: Wheat Ridge (8 mi, 50.3°F a year); Lakewood (10 mi, 50.4°F a year)115,302 people · 3 mi SW
- Broomfield, COalso near: Brighton (11 mi, 50.6°F a year); Boulder (12 mi, 51.5°F a year)78,323 people · 4 mi NW
- Lafayette, CO30,587 people · 8 mi NW
- Sherrelwood, CO19,368 people · 4 mi S
- Welby, CO16,232 people · 5 mi SE
- Federal Heights, CO13,971 people · 2 mi S
- Derby, CO8,692 people · 7 mi SE
- Twin Lakes, CO8,279 people · 5 mi S
- Shaw Heights, CO5,309 people · 3 mi SW
Source: Census Bureau 2024 Gazetteer (place centers) and Vintage 2024 population estimates. Distance and direction from the station to each place's center.
Questions about Northglenn's climate
What is the coldest month in Northglenn?
December, with a normal high of 48°F and a normal low of 19°F. The warmest is July (91°F by day, 59°F at night).
Does it snow in Northglenn?
Yes: 45 inches in a normal year, falling on 24 days with 0.1 inch or more, the most in March (8.2 inches).
What is the rainiest month in Northglenn?
May, with 2.35 in of precipitation in a normal year; the driest is January with 0.45 in.
What plant hardiness zone is Northglenn in?
The USDA's 2023 map puts Northglenn in zone 6a across its 3 ZIP code areas (6a in 80233, the largest). By the same method at Northglenn's NOAA station, the coldest night of a typical year reaches −7°F (28 years, 1991-2020): zone 6a.
How late can frost come in Northglenn?
In half of years the last 32°F night comes after May 2; in one year in ten it comes after May 14. Waiting until May 14 leaves about a one-in-ten chance of a later frost.
Nearby and next
- Colorado climateThe statewide normals and every place in the state
- Brighton, CO10 miles from this station, 50.6°F a year
- Wheat Ridge, CO10 miles from this station, 50.3°F a year
- Denver Water Dept, CO12 miles from this station, 53.3°F a year
- Lakewood, CO12 miles from this station, 50.4°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made