Northglenn weather in September

In September, Northglenn sees average daytime highs of 77°F and overnight lows near 49°F, with 1.5 in of precipitation across 6.1 wet days and about 12.3 hours of daylight. It is the 4th-warmest and 8th-wettest month of the year here.

Highs ease over the month, from about 81°F in the first days to 72°F by the end. The sky is clear or mostly clear about 53% of the time in September, and the air most often feels dry.

Daylight stretches from about 12 h 54 min at the start of September to 11 h 36 min by month's end. Set against the rest of the year, September is Northglenn's 1st-clearest and 8th-windiest month. For the whole year in context, see Northglenn's year-round climate.

Daytime high
77°
4th warmest
Overnight low
49°
9th coldest
Precipitation
1.5 in
6.1 wet days
Daylight
12 h 18 min
5:47 AM – 6:02 PM
Cloud cover
40%
1st clearest
Wind
5 mph
8th windiest
Solar energy
5.45 kWh/m²
Travel score
7.6
out of 10

Northglenn is city in Adams and Weld counties in Colorado, United States.

Density
2,032/km²
people per km²
Founded
1969

Air quality: WHO Ambient Air Quality Database. Density & description: Wikidata (CC0), GeoNames.

Temperature in September

Average highAverage lowShaded bands: 10–90% of days

Highs ease over the month, from about 81°F in the first days to 72°F by the end.

A typical September day in Northglenn reaches about 77°F in the afternoon and slips back to 49°F overnight — a 27°F spread between the day's warmth and the night's chill. On most days the high lands between 64°F and 87°F. Set against its neighbours, September runs about 7°F cooler than August and about 13°F warmer than October.

40°60°80°151015202530
Avg high (°F)Avg low (°F)
18255
28255
38154
48154
58153
68053
78053
88052
97952
107952
117851
127851
137850
147750
157750
167649
177649
187648
197548
207547
217447
227447
237446
247346
257346
267345
277245
287245
297144
307144

How September really feels in Northglenn

Once humidity and wind are folded in, September averages 0 days that feel above 90°F and 0 that feel at or below 32°F — the comfort signal a plain temperature reading hides.

Days feeling ≥ 90°F
0
heat index over the day's high
Days feeling ≤ 32°F
0
wind chill below the day's low

September sits comfortably in between — no days that feel dangerously hot or drop to a hard freeze once humidity and wind are folded in.

Northglenn weather by month

How September compares with the rest of the year at a glance. September is the 4th-warmest and 8th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°F)Rainfall (inches)Wet daysSnow daysDaylight (hours)Travel score
Jan41° / 18°0.84.74.89.50.2
Feb44° / 20°0.85.65.510.41.0
Mar54° / 27°1.77.6511.73.5
Apr60° / 34°2.79.94.3134.9
May69° / 44°3.311.90.714.26.1
Jun80° / 53°2.19.2014.86.6
Jul86° / 59°1.78.5014.55.2
Aug84° / 57°1.67.3013.66.1
Sep77° / 49°1.56.10.412.37.6
Oct64° / 37°1.66.32.110.96.4
Nov51° / 26°1.15.84.69.82.9
Dec41° / 18°0.84.64.79.20.3

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 53% of the time in September, the clearest month of the year.

Beyond those clear spells, partly cloudy skies cover about 20% of September, with mostly cloudy or overcast conditions the remaining 27%. Skies tend to open up as the month goes on.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
17327
27327
37327
47228
57228
67228
77228
87327
97327
107327
117327
127327
137327
147327
157327
167327
177327
187426
197426
207426
217327
227327
237327
247327
257228
267129
277129
287129
297129
307129

Chance of precipitation in September

Any precipitationSnow

Northglenn gets around 1.5 in of rain and snow over 6.1 wet days in September. The line is the day-by-day chance of measurable precipitation.

Day to day, the chance of measurable precipitation averages around 21% and peaks near 23% on the wettest days, and about 0 day brings snow.

0%10%20%30%151015202530
Rain chance (%)Snow chance (%)
1180
2190
3190
4191
5201
6201
7211
8211
9211
10221
11221
12221
13231
14231
15231
16232
17222
18222
19222
20212
21212
22212
23212
24212
25212
26212
27212
28212
29212
30213

Humidity in September

DryComfortableHumidMuggyOppressiveMiserable

Most of September feels dry — the stacked bands show each day's mix of comfort levels, read off the dew point.

By dew point, September lands in the dry band about 98% of days. It rarely turns muggy — the humid and sticky bands barely register.

0%25%50%75%100%151015202530
Dry (%)Comfortable (%)
1964
2964
3964
4973
5973
6973
7973
8973
9973
10982
11982
12982
13982
14982
15982
16991
17991
18991
19991
20991
211000
221000
231000
241000
251000
261000
271000
281000
291000
301000

Wind in September

Winds average 5 mph in September.

Across September, daily wind ranges from about 4 mph on the calmest days to 5 mph at its breeziest. It stays fairly steady from day to day.

0246810151015202530
Wind speed (mph)Feels
14calm
24calm
34calm
44calm
54calm
64calm
74calm
84calm
94calm
104calm
115calm
125calm
135calm
145calm
155calm
165calm
175calm
185calm
195calm
205calm
215calm
225calm
235calm
245calm
255calm
265calm
275calm
285calm
295calm
305calm

Sunrise & sunset in September

DaylightNight

Daylight runs from about 12 h 54 min at the start of September to 11 h 36 min by month's end. The lit band spans sunrise to sunset each day.

Days shrink by about 78 minutes over September. Sunrise moves from 5:32 AM to 6:00 AM, and sunset from 6:27 PM to 5:38 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
112.95:326:27
212.95:336:26
312.85:346:24
412.85:356:22
512.75:366:21
612.75:376:19
712.75:386:17
812.65:396:16
912.65:406:14
1012.55:416:12
1112.55:426:11
1212.45:436:09
1312.45:446:07
1412.35:456:05
1512.35:466:04
1612.35:476:02
1712.25:476:00
1812.25:485:59
1912.15:495:57
2012.15:505:55
2112.05:515:53
2212.05:525:52
2311.95:535:50
2411.95:545:48
2511.95:555:47
2611.85:565:45
2711.85:575:43
2811.75:585:42
2911.75:595:40
3011.66:005:38

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 5.45 kWh/m².

For context, solar energy here swings from a low near 2.49 kWh/m² to a high of 7.42 kWh/m² in June across the year — September's 5.45 kWh/m² falls in the middle.

0246151015202530
Solar energy (kWh/m²)Level
16.0Intense
26.0Intense
36.0Bright
45.9Bright
55.9Bright
65.8Bright
75.8Bright
85.8Bright
95.7Bright
105.7Bright
115.6Bright
125.6Bright
135.5Bright
145.5Bright
155.5Bright
165.4Bright
175.4Bright
185.3Bright
195.3Bright
205.2Bright
215.2Bright
225.1Bright
235.1Bright
245.0Bright
255.0Bright
265.0Bright
274.9Bright
284.9Bright
294.8Bright
304.8Bright
Planning a trip in September

Is September a good time to visit Northglenn?

Our two travel scores rate September for general sightseeing and for beach or pool weather — 0 (poor) to 10 (ideal).

7.6
Sightseeing
1st-best month of the year
6.6
Beach & pool
4th-best month of the year

September is one of the better times to visit Northglenn for general sightseeing. The water and warmth also suit a beach or pool day.

What to pack for Northglenn in September

From September's temperature range, rain chance, sun and wind — what's worth putting in the bag.

In September, Northglenn sees daytime highs around 77°F and nights near 49°F. Worth packing: light clothes and sun protection. About 6 days see rain.

light clothessun protection

UV index in Northglenn in September

LowModerateHighVery highExtreme

Clear-sky midday UV in September peaks around 7 — enough to warrant sun protection. The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Northglenn peaks around July 12 at about 11 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near December 23 at about 2 (low).

The index reaches 3 or more — the level where the WHO recommends sun protection — in 10 months of the year.

025710JanFebMarAprMayJunJulAugSepOctNovDecModerateHighVery highExtremeVery highHighModerateJul 12UV 11Dec 23UV 2
UV index (midday)Level
Jan2Low
Feb4Moderate
Mar7High
Apr6High
May7Very high
Jun10Extreme
Jul11Extreme
Aug10Very high
Sep7Very high
Oct5High
Nov3Moderate
Dec2Low

Air quality in Northglenn in September

GoodModeratePoorUnhealthyVery unhealthy

Average fine-particle pollution (PM2.5) through the year — so you can see where September falls, not just the annual average.

Air quality in Northglenn is worst in August — around 21 µg/m³ PM2.5 (moderate), about 1.6× the cleanest month (May, 13 µg/m³).

Modeled monthly averages (CAMS reanalysis, 2015–2024).

0102030JanFebMarAprMayJunJulAugSepOctNovDecModerateAug 1620 µg/m³May 1113 µg/m³
PM2.5 (µg/m³)Level
Jan17Moderate
Feb15Moderate
Mar16Moderate
Apr13Moderate
May13Moderate
Jun14Moderate
Jul14Moderate
Aug21Moderate
Sep13Moderate
Oct15Moderate
Nov15Moderate
Dec16Moderate
Location & terrain

Where is Northglenn?

Northglenn sits at 39.9°N, 105.0°W, 5,377 ft above sea level, in United States. The nearest listed city is Thornton, 1.2 mi away.

Topography around Northglenn

How much the land rises and falls, and what covers it, within 2, 10 and 50 miles of Northglenn.

Within 2 miles, the terrain around Northglenn has only modest variations in elevation — a maximum elevation change of 394 ft around an average of 5,364 ft above sea level; within 10 miles, significant variations in elevation — a maximum elevation change of 951 ft; within 50 miles, extreme variations in elevation — a maximum elevation change of 9,708 ft.

The land around Northglenn is covered by artificial surfaces (66%) within 2 miles, artificial surfaces (42%) and grassland (36%) within 10 miles, and grassland (42%) and trees (31%) within 50 miles.

2 miles
394 ft
10 miles
951 ft
50 miles
9,708 ft
treesgrasslandcroplandartificial surfacesbare terrainwatermoss and lichen
September weather nearby: Thornton 1.2 mi · Sherrelwood 3.1 mi · Westminster 4.3 mi · Broomfield 5.6 mi · Commerce City 6.2 mi · Arvada 8.1 mi · Lafayette 9.3 mi · Wheat Ridge 9.3 mi

United States travel facts

Power plugs
Type A / B
120 V · 60 Hz
Prices
≈ 100% of US
price level, 2025
GDP per capita
$90,027
2025
Happiness
6.8 / 10
World Happiness, 2025
Safe drinking water
98%
of population, 2024
Homicide rate
5.8
per 100k, 2023
Road deaths
12.7
per 100k/yr, 2019
Income group
High
World Bank
Religion
Protestant 47%unaffiliated 23%Roman Catholic 21%Jewish 2%

Sources: World Bank, US State Department, World Happiness Report, WHO/UNICEF, EF EPI, CIA World Factbook.

Data sources

Temperature, precipitation, cloud, humidity, wind and solar figures are a 1991–2020 climatology for Northglenn (39.8855°, -104.9872°, elevation 5,377 ft), computed from hourly ERA5 reanalysis — contains modified Copernicus Climate Change Service information. Sun figures are astronomical calculations, not observations. City data © GeoNames, CC BY 4.0. Map outlines from Natural Earth (public domain); interactive map © Google. UV index is derived from CAMS (Copernicus Atmosphere Monitoring Service) clear-sky UV data — contains modified Copernicus Atmosphere Monitoring Service information. Monthly air-quality (PM2.5) seasonality is from the CAMS EAC4 reanalysis (Copernicus Atmosphere Monitoring Service), scaled to the WHO annual mean where available. Topography is sampled from the Copernicus DEM GLO-90 elevation model (© ESA/Airbus) and ESA WorldCover 2021 land cover (CC BY 4.0).