Mandan weather in September

In September, Mandan sees average daytime highs of 71°F and overnight lows near 47°F, with 1.8 in of rain across 6.4 wet days and about 12.4 hours of daylight. It is the 4th-warmest and 6th-wettest month of the year here.

Highs ease over the month, from about 77°F in the first days to 65°F by the end. The sky is clear or mostly clear about 47% of the time in September, and the air most often feels dry.

Daylight stretches from about 13 h 12 min at the start of September to 11 h 30 min by month's end. Set against the rest of the year, September is Mandan's 3rd-clearest and 9th-windiest month. For the whole year in context, see Mandan's year-round climate.

Daytime high: 71°; 4th warmest
Overnight low: 47°; 9th coldest
Rainfall: 1.8 in; 6.4 wet days
Daylight: 12 h 18 min; 6:28 AM – 6:48 PM
Cloud cover: 46%; 3rd clearest
Wind: 9 mph; 9th windiest
Solar energy: 4.34 kWh/m²
Travel score: 7.3; out of 10

Mandan is city in North Dakota, United States.

Density: 737/km²; people per km²
Founded: 1881

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

← August Mandan year-round climate October →Best places to visit in September

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Temperature in September

Average highAverage lowShaded bands: 10–90% of days

Highs ease over the month, from about 77°F in the first days to 65°F by the end.

A typical September day in Mandan reaches about 71°F in the afternoon and slips back to 47°F overnight — a 23°F spread between the day's warmth and the night's chill. On most days the high lands between 57°F and 84°F. Set against its neighbours, September runs about 10°F cooler than August and about 15°F warmer than October.

	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26	27	28	29	30
Avg high (°F)	78	77	77	76	76	75	75	74	74	73	73	72	72	71	71	70	70	69	69	69	68	68	67	67	66	66	65	65	64	64
Avg low (°F)	54	53	53	52	52	51	51	51	50	50	49	49	48	48	47	47	47	46	46	46	45	45	44	44	44	43	43	42	42	41

	Avg high (°F)	Avg low (°F)
1	78	54
2	77	53
3	77	53
4	76	52
5	76	52
6	75	51
7	75	51
8	74	51
9	74	50
10	73	50
11	73	49
12	72	49
13	72	48
14	71	48
15	71	47
16	70	47
17	70	47
18	69	46
19	69	46
20	69	46
21	68	45
22	68	45
23	67	44
24	67	44
25	66	44
26	66	43
27	65	43
28	65	42
29	64	42
30	64	41

How September really feels in Mandan

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

heat index over the day's high

Days feeling ≤ 32°F

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.

Mandan weather by month

How September compares with the rest of the year at a glance. September is the 4th-warmest and 6th-wettest month here — the current month is highlighted below.

Month	High / Low (°F)	Rainfall (inches)	Wet days	Snow days	Daylight (hours)	Travel score
Jan	22° / 6°	0.6	4.5	4.9	8.8	0.0
Feb	26° / 9°	0.7	4.7	4.7	10	0.0
Mar	38° / 20°	1.1	5.3	4.1	11.6	0.3
Apr	53° / 32°	1.9	7.7	3	13.3	3.1
May	65° / 44°	2.9	10.3	0.4	14.8	5.8
Jun	75° / 54°	3.8	11.5	0	15.6	6.6
Jul	81° / 59°	3.0	10	0	15.3	6.7
Aug	81° / 57°	2.3	7.5	0	14	7.2
Sep	71° / 47°	1.8	6.4	0	12.4	7.3
Oct	55° / 35°	1.8	6.4	1.7	10.6	4.0
Nov	38° / 21°	0.8	4.2	3.5	9.2	0.2
Dec	26° / 10°	0.7	4.1	4.7	8.4	0.0

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 47% of the time in September.

Beyond those clear spells, partly cloudy skies cover about 15% of September, with mostly cloudy or overcast conditions the remaining 39%.

	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26	27	28	29	30
Clearer (%)	69	68	67	67	66	66	66	65	64	63	62	61	61	60	60	59	59	59	59	59	59	59	58	59	58	58	58	58	58	57
Cloudier (%)	31	32	33	33	34	34	34	35	36	37	38	39	39	40	40	41	41	41	41	41	41	41	42	41	42	42	42	42	42	43

	Clearer (%)	Cloudier (%)
1	69	31
2	68	32
3	67	33
4	67	33
5	66	34
6	66	34
7	66	34
8	65	35
9	64	36
10	63	37
11	62	38
12	61	39
13	61	39
14	60	40
15	60	40
16	59	41
17	59	41
18	59	41
19	59	41
20	59	41
21	59	41
22	59	41
23	58	42
24	59	41
25	58	42
26	58	42
27	58	42
28	58	42
29	58	42
30	57	43

Chance of precipitation in September

Any precipitation

Mandan gets around 1.8 in of rain over 6.4 wet days in September. The line is the day-by-day chance of measurable precipitation.

Day to day, the chance of measurable rain averages around 22% and peaks near 23% on the wettest days.

	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26	27	28	29	30
Rain chance (%)	21	21	21	21	21	21	21	21	21	22	22	22	22	22	23	23	23	23	23	22	22	22	22	21	21	21	21	21	21	21

	Rain chance (%)
1	21
2	21
3	21
4	21
5	21
6	21
7	21
8	21
9	21
10	22
11	22
12	22
13	22
14	22
15	23
16	23
17	23
18	23
19	23
20	22
21	22
22	22
23	22
24	21
25	21
26	21
27	21
28	21
29	21
30	21

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 85% of days. It rarely turns muggy — the humid and sticky bands barely register.

	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26	27	28	29	30
Dry (%)	64	65	67	70	71	73	75	76	78	80	82	83	84	86	86	88	89	89	90	91	92	93	94	94	95	96	97	97	98	98
Comfortable (%)	22	21	20	19	19	18	17	16	15	14	13	13	12	11	11	10	9	9	8	8	7	6	5	5	4	4	3	3	2	2
Humid (%)	12	12	11	10	9	8	7	7	6	5	5	4	4	3	3	2	2	2	2	1	1	1	1	1	1	0	0	0	0	0
Muggy (%)	2	2	2	1	1	1	1	1	1	1	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0

	Dry (%)	Comfortable (%)	Humid (%)	Muggy (%)
1	64	22	12	2
2	65	21	12	2
3	67	20	11	2
4	70	19	10	1
5	71	19	9	1
6	73	18	8	1
7	75	17	7	1
8	76	16	7	1
9	78	15	6	1
10	80	14	5	1
11	82	13	5	0
12	83	13	4	0
13	84	12	4	0
14	86	11	3	0
15	86	11	3	0
16	88	10	2	0
17	89	9	2	0
18	89	9	2	0
19	90	8	2	0
20	91	8	1	0
21	92	7	1	0
22	93	6	1	0
23	94	5	1	0
24	94	5	1	0
25	95	4	1	0
26	96	4	0	0
27	97	3	0	0
28	97	3	0	0
29	98	2	0	0
30	98	2	0	0

Wind in September

Winds average 9 mph in September.

Across September, daily wind ranges from about 9 mph on the calmest days to 10 mph at its breeziest. It stays fairly steady from day to day.

	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26	27	28	29	30
Wind speed (mph)	9	9	9	9	9	9	9	9	9	9	9	9	9	9	9	9	9	9	9	9	9	10	10	10	10	10	10	10	10	10
Feels	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze

	Wind speed (mph)	Feels
1	9	light breeze
2	9	light breeze
3	9	light breeze
4	9	light breeze
5	9	light breeze
6	9	light breeze
7	9	light breeze
8	9	light breeze
9	9	light breeze
10	9	light breeze
11	9	light breeze
12	9	light breeze
13	9	light breeze
14	9	light breeze
15	9	light breeze
16	9	light breeze
17	9	light breeze
18	9	light breeze
19	9	light breeze
20	9	light breeze
21	9	light breeze
22	10	light breeze
23	10	light breeze
24	10	light breeze
25	10	light breeze
26	10	light breeze
27	10	light breeze
28	10	light breeze
29	10	light breeze
30	10	light breeze

Sunrise & sunset in September

DaylightNight

Daylight runs from about 13 h 12 min at the start of September to 11 h 30 min by month's end. The lit band spans sunrise to sunset each day.

Days shrink by about 102 minutes over September. Sunrise moves from 6:08 AM to 6:47 AM, and sunset from 7:19 PM to 6:19 PM.

	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26	27	28	29	30
Daylight (h)	13.2	13.1	13.1	13.0	13.0	12.9	12.8	12.8	12.7	12.7	12.6	12.6	12.5	12.4	12.4	12.3	12.3	12.2	12.2	12.1	12.0	12.0	11.9	11.9	11.8	11.8	11.7	11.6	11.6	11.5
Sunrise (AM)	6:08	6:09	6:11	6:12	6:13	6:15	6:16	6:17	6:19	6:20	6:21	6:23	6:24	6:25	6:27	6:28	6:29	6:31	6:32	6:33	6:35	6:36	6:37	6:39	6:40	6:42	6:43	6:44	6:46	6:47
Sunset (PM)	7:19	7:17	7:15	7:13	7:11	7:08	7:06	7:04	7:02	7:00	6:58	6:56	6:54	6:52	6:50	6:48	6:46	6:44	6:41	6:39	6:37	6:35	6:33	6:31	6:29	6:27	6:25	6:23	6:21	6:19

	Daylight (h)	Sunrise (AM)	Sunset (PM)
1	13.2	6:08	7:19
2	13.1	6:09	7:17
3	13.1	6:11	7:15
4	13.0	6:12	7:13
5	13.0	6:13	7:11
6	12.9	6:15	7:08
7	12.8	6:16	7:06
8	12.8	6:17	7:04
9	12.7	6:19	7:02
10	12.7	6:20	7:00
11	12.6	6:21	6:58
12	12.6	6:23	6:56
13	12.5	6:24	6:54
14	12.4	6:25	6:52
15	12.4	6:27	6:50
16	12.3	6:28	6:48
17	12.3	6:29	6:46
18	12.2	6:31	6:44
19	12.2	6:32	6:41
20	12.1	6:33	6:39
21	12.0	6:35	6:37
22	12.0	6:36	6:35
23	11.9	6:37	6:33
24	11.9	6:39	6:31
25	11.8	6:40	6:29
26	11.8	6:42	6:27
27	11.7	6:43	6:25
28	11.6	6:44	6:23
29	11.6	6:46	6:21
30	11.5	6:47	6:19

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 4.34 kWh/m².

For context, solar energy here swings from a low near 1.44 kWh/m² to a high of 6.72 kWh/m² in July across the year — September's 4.34 kWh/m² falls in the middle.

	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26	27	28	29	30
Solar energy (kWh/m²)	5.1	5.1	5.0	5.0	4.9	4.8	4.8	4.7	4.7	4.6	4.6	4.5	4.5	4.4	4.3	4.3	4.2	4.2	4.2	4.1	4.0	4.0	4.0	3.9	3.9	3.8	3.8	3.7	3.7	3.6
Level	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate

	Solar energy (kWh/m²)	Level
1	5.1	Bright
2	5.1	Bright
3	5.0	Bright
4	5.0	Bright
5	4.9	Bright
6	4.8	Bright
7	4.8	Bright
8	4.7	Bright
9	4.7	Bright
10	4.6	Bright
11	4.6	Bright
12	4.5	Bright
13	4.5	Bright
14	4.4	Bright
15	4.3	Bright
16	4.3	Bright
17	4.2	Bright
18	4.2	Bright
19	4.2	Bright
20	4.1	Bright
21	4.0	Bright
22	4.0	Bright
23	4.0	Moderate
24	3.9	Moderate
25	3.9	Moderate
26	3.8	Moderate
27	3.8	Moderate
28	3.7	Moderate
29	3.7	Moderate
30	3.6	Moderate

Planning a trip in September

Hazard calendar for Mandan

In seasonPeak

In September, Mandan sits inside its rainy season season. The full year is below, with each hazard's peak months called out.

Mandan's rainy season runs April–October, when most of the year's rain falls.

Rainy season

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Is September a good time to visit Mandan?

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

7.3

Sightseeing

1st-best month of the year

4.6

Beach & pool

4th-best month of the year

September is one of the better times to visit Mandan for general sightseeing.

What to pack for Mandan in September

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

In September, Mandan sees daytime highs around 71°F and nights near 47°F. Little to plan around — just the basics. About 6 days see rain.

UV index in Mandan in September

LowModerateHighVery highExtreme

Clear-sky midday UV in September peaks around 5 — enough to warrant sun protection. The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Mandan peaks around June 22 at about 8 (very high) — sunscreen and a hat are worth it in the middle of the day. It bottoms out near December 20 at about 1 (low).

The index reaches 3 or more — the level where the WHO recommends sun protection — in 8 months of the year.

	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
UV index (midday)	1	2	3	4	6	8	8	6	5	4	2	1
Level	Low	Low	Moderate	Moderate	High	Very high	Very high	High	High	Moderate	Low	Low

	UV index (midday)	Level
Jan	1	Low
Feb	2	Low
Mar	3	Moderate
Apr	4	Moderate
May	6	High
Jun	8	Very high
Jul	8	Very high
Aug	6	High
Sep	5	High
Oct	4	Moderate
Nov	2	Low
Dec	1	Low

Location & terrain

Where is Mandan?

Mandan sits at 46.8°N, 100.9°W, 1,647 ft above sea level, in United States. The nearest listed city is Bismarck, 5.0 mi away.

Topography around Mandan

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

Within 2 miles, the terrain around Mandan has only modest variations in elevation — a maximum elevation change of 341 ft around an average of 1,709 ft above sea level; within 10 miles, only modest variations in elevation — a maximum elevation change of 499 ft; within 50 miles, significant variations in elevation — a maximum elevation change of 899 ft.

The land around Mandan is covered by grassland (44%) and artificial surfaces (26%) within 2 miles, grassland (63%) and cropland (21%) within 10 miles, and grassland (63%) and cropland (33%) within 50 miles.

2 miles

341 ft

grassland 44%

10 miles

499 ft

grassland 63%

50 miles

899 ft

grassland 63%

treesgrasslandcroplandartificial surfacesbare terrainwater

← August Mandan year-round climate October →Best places to visit in September

September weather nearby: Bismarck 5.0 mi · Dickinson 90 mi · Minot 99 mi · Jamestown 103 mi · Aberdeen 149 mi · Williston 157 mi · West Fargo 188 mi · Fargo 194 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

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 Mandan (46.8267°, -100.8896°, elevation 1,647 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. Topography is sampled from the Copernicus DEM GLO-90 elevation model (© ESA/Airbus) and ESA WorldCover 2021 land cover (CC BY 4.0).

	Avg high (°F)	Avg low (°F)
1	78	54
2	77	53
3	77	53
4	76	52
5	76	52
6	75	51
7	75	51
8	74	51
9	74	50
10	73	50
11	73	49
12	72	49
13	72	48
14	71	48
15	71	47
16	70	47
17	70	47
18	69	46
19	69	46
20	69	46
21	68	45
22	68	45
23	67	44
24	67	44
25	66	44
26	66	43
27	65	43
28	65	42
29	64	42
30	64	41

	Clearer (%)	Cloudier (%)
1	69	31
2	68	32
3	67	33
4	67	33
5	66	34
6	66	34
7	66	34
8	65	35
9	64	36
10	63	37
11	62	38
12	61	39
13	61	39
14	60	40
15	60	40
16	59	41
17	59	41
18	59	41
19	59	41
20	59	41
21	59	41
22	59	41
23	58	42
24	59	41
25	58	42
26	58	42
27	58	42
28	58	42
29	58	42
30	57	43

	Rain chance (%)
1	21
2	21
3	21
4	21
5	21
6	21
7	21
8	21
9	21
10	22
11	22
12	22
13	22
14	22
15	23
16	23
17	23
18	23
19	23
20	22
21	22
22	22
23	22
24	21
25	21
26	21
27	21
28	21
29	21
30	21

	Dry (%)	Comfortable (%)	Humid (%)	Muggy (%)
1	64	22	12	2
2	65	21	12	2
3	67	20	11	2
4	70	19	10	1
5	71	19	9	1
6	73	18	8	1
7	75	17	7	1
8	76	16	7	1
9	78	15	6	1
10	80	14	5	1
11	82	13	5	0
12	83	13	4	0
13	84	12	4	0
14	86	11	3	0
15	86	11	3	0
16	88	10	2	0
17	89	9	2	0
18	89	9	2	0
19	90	8	2	0
20	91	8	1	0
21	92	7	1	0
22	93	6	1	0
23	94	5	1	0
24	94	5	1	0
25	95	4	1	0
26	96	4	0	0
27	97	3	0	0
28	97	3	0	0
29	98	2	0	0
30	98	2	0	0

	Avg high (°F)	Avg low (°F)
1	78	54
2	77	53
3	77	53
4	76	52
5	76	52
6	75	51
7	75	51
8	74	51
9	74	50
10	73	50
11	73	49
12	72	49
13	72	48
14	71	48
15	71	47
16	70	47
17	70	47
18	69	46
19	69	46
20	69	46
21	68	45
22	68	45
23	67	44
24	67	44
25	66	44
26	66	43
27	65	43
28	65	42
29	64	42
30	64	41

	Clearer (%)	Cloudier (%)
1	69	31
2	68	32
3	67	33
4	67	33
5	66	34
6	66	34
7	66	34
8	65	35
9	64	36
10	63	37
11	62	38
12	61	39
13	61	39
14	60	40
15	60	40
16	59	41
17	59	41
18	59	41
19	59	41
20	59	41
21	59	41
22	59	41
23	58	42
24	59	41
25	58	42
26	58	42
27	58	42
28	58	42
29	58	42
30	57	43

	Rain chance (%)
1	21
2	21
3	21
4	21
5	21
6	21
7	21
8	21
9	21
10	22
11	22
12	22
13	22
14	22
15	23
16	23
17	23
18	23
19	23
20	22
21	22
22	22
23	22
24	21
25	21
26	21
27	21
28	21
29	21
30	21

	Dry (%)	Comfortable (%)	Humid (%)	Muggy (%)
1	64	22	12	2
2	65	21	12	2
3	67	20	11	2
4	70	19	10	1
5	71	19	9	1
6	73	18	8	1
7	75	17	7	1
8	76	16	7	1
9	78	15	6	1
10	80	14	5	1
11	82	13	5	0
12	83	13	4	0
13	84	12	4	0
14	86	11	3	0
15	86	11	3	0
16	88	10	2	0
17	89	9	2	0
18	89	9	2	0
19	90	8	2	0
20	91	8	1	0
21	92	7	1	0
22	93	6	1	0
23	94	5	1	0
24	94	5	1	0
25	95	4	1	0
26	96	4	0	0
27	97	3	0	0
28	97	3	0	0
29	98	2	0	0
30	98	2	0	0

	Avg high (°F)	Avg low (°F)
1	78	54
2	77	53
3	77	53
4	76	52
5	76	52
6	75	51
7	75	51
8	74	51
9	74	50
10	73	50
11	73	49
12	72	49
13	72	48
14	71	48
15	71	47
16	70	47
17	70	47
18	69	46
19	69	46
20	69	46
21	68	45
22	68	45
23	67	44
24	67	44
25	66	44
26	66	43
27	65	43
28	65	42
29	64	42
30	64	41

	Clearer (%)	Cloudier (%)
1	69	31
2	68	32
3	67	33
4	67	33
5	66	34
6	66	34
7	66	34
8	65	35
9	64	36
10	63	37
11	62	38
12	61	39
13	61	39
14	60	40
15	60	40
16	59	41
17	59	41
18	59	41
19	59	41
20	59	41
21	59	41
22	59	41
23	58	42
24	59	41
25	58	42
26	58	42
27	58	42
28	58	42
29	58	42
30	57	43

	Rain chance (%)
1	21
2	21
3	21
4	21
5	21
6	21
7	21
8	21
9	21
10	22
11	22
12	22
13	22
14	22
15	23
16	23
17	23
18	23
19	23
20	22
21	22
22	22
23	22
24	21
25	21
26	21
27	21
28	21
29	21
30	21

	Dry (%)	Comfortable (%)	Humid (%)	Muggy (%)
1	64	22	12	2
2	65	21	12	2
3	67	20	11	2
4	70	19	10	1
5	71	19	9	1
6	73	18	8	1
7	75	17	7	1
8	76	16	7	1
9	78	15	6	1
10	80	14	5	1
11	82	13	5	0
12	83	13	4	0
13	84	12	4	0
14	86	11	3	0
15	86	11	3	0
16	88	10	2	0
17	89	9	2	0
18	89	9	2	0
19	90	8	2	0
20	91	8	1	0
21	92	7	1	0
22	93	6	1	0
23	94	5	1	0
24	94	5	1	0
25	95	4	1	0
26	96	4	0	0
27	97	3	0	0
28	97	3	0	0
29	98	2	0	0
30	98	2	0	0