Arvayheer weather in September

In September, Arvayheer sees average daytime highs of 16°C and overnight lows near 3°C, with 23 mm of precipitation across 5.2 wet days and about 12.3 hours of daylight. It is the 4th-warmest and 5th-wettest month of the year here.

Highs ease over the month, from about 19°C in the first days to 13°C by the end. The sky is clear or mostly clear about 48% 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 Arvayheer's 6th-clearest and 5th-windiest month. For the whole year in context, see Arvayheer's year-round climate.

Daytime high: 16°; 4th warmest
Overnight low: 3°; 9th coldest
Precipitation: 23 mm; 5.2 wet days
Daylight: 12 h 18 min; 6:54 AM – 7:13 PM
Cloud cover: 44%; 6th clearest
Wind: 12 km/h; 5th windiest
Solar energy: 4.74 kWh/m²
Travel score: 5.6; out of 10

Arvayheer is main settlement in the district of the same name.

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

← August Arvayheer 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 19°C in the first days to 13°C by the end.

A typical September day in Arvayheer reaches about 16°C in the afternoon and slips back to 3°C overnight — a 13°C spread between the day's warmth and the night's chill. On most days the high lands between 9°C and 22°C. Set against its neighbours, September runs about 5°C cooler than August and about 8°C 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 (°C)	19	19	19	18	18	18	18	17	17	17	17	17	16	16	16	16	16	15	15	15	15	15	14	14	14	14	13	13	13	12
Avg low (°C)	7	7	6	6	6	6	5	5	5	4	4	4	4	3	3	3	3	2	2	2	2	1	1	1	0	0	0	0	-1	-1

	Avg high (°C)	Avg low (°C)
1	19	7
2	19	7
3	19	6
4	18	6
5	18	6
6	18	6
7	18	5
8	17	5
9	17	5
10	17	4
11	17	4
12	17	4
13	16	4
14	16	3
15	16	3
16	16	3
17	16	3
18	15	2
19	15	2
20	15	2
21	15	2
22	15	1
23	14	1
24	14	1
25	14	0
26	14	0
27	13	0
28	13	0
29	13	-1
30	12	-1

How September really feels in Arvayheer

Once humidity and wind are folded in, September averages 0 days that feel above 32°C and 16 that feel at or below 0°C — the comfort signal a plain temperature reading hides.

Days feeling ≥ 32°C

heat index over the day's high

Days feeling ≤ 0°C

wind chill below the day's low

The story in September is cold — wind chill drags the overnight "feels like" below the raw low.

Arvayheer weather by month

How September compares with the rest of the year at a glance. September is the 4th-warmest and 5th-wettest month here — the current month is highlighted below.

Month	High / Low (°C)	Rainfall (mm)	Wet days	Snow days	Daylight (hours)	Travel score
Jan	-10° / -22°	1	0.3	0.8	8.8	0.0
Feb	-6° / -19°	3	0.9	1.2	10	0.0
Mar	1° / -12°	7	2.2	2.9	11.6	0.0
Apr	9° / -4°	13	4	3.1	13.3	2.2
May	16° / 2°	27	5.9	2.1	14.7	5.3
Jun	21° / 9°	43	8.4	0.2	15.5	6.6
Jul	23° / 12°	62	11	0	15.2	6.6
Aug	21° / 10°	50	9	0.1	14	6.7
Sep	16° / 3°	23	5.2	1.1	12.3	5.6
Oct	8° / -5°	10	2.7	2.5	10.7	1.7
Nov	-2° / -13°	4	1.2	1.7	9.2	0.0
Dec	-8° / -19°	2	0.4	0.9	8.5	0.0

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 48% of the time in September.

Beyond those clear spells, partly cloudy skies cover about 20% of September, with mostly cloudy or overcast conditions the remaining 31%. Skies tend to open up as the month goes on.

	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 (%)	58	58	59	59	60	61	62	62	64	65	66	67	68	70	70	71	73	73	73	74	74	74	74	75	74	74	74	75	75	74
Cloudier (%)	42	42	41	41	40	39	38	38	36	35	34	33	32	30	30	29	27	27	27	26	26	26	26	25	26	26	26	25	25	26

	Clearer (%)	Cloudier (%)
1	58	42
2	58	42
3	59	41
4	59	41
5	60	40
6	61	39
7	62	38
8	62	38
9	64	36
10	65	35
11	66	34
12	67	33
13	68	32
14	70	30
15	70	30
16	71	29
17	73	27
18	73	27
19	73	27
20	74	26
21	74	26
22	74	26
23	74	26
24	75	25
25	74	26
26	74	26
27	74	26
28	75	25
29	75	25
30	74	26

Chance of precipitation in September

Any precipitationSnow

Arvayheer gets around 23 mm of rain and snow over 5.2 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 17% and peaks near 21% on the wettest days, and about 1 day brings snow. The odds ease toward the end of the month.

	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	20	20	20	20	20	20	20	19	19	18	18	18	17	16	16	15	15	14	13	13	12	12	11	11	11
Snow chance (%)	1	1	1	1	2	2	2	2	3	3	3	4	4	4	4	4	4	5	5	5	5	5	5	5	5	5	5	6	6	6

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

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 100% 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 (%)	100	100	100	100	100	100	100	100	100	100	100	100	100	100	100	100	100	100	100	100	100	100	100	100	100	100	100	100	100	100

	Dry (%)
1	100
2	100
3	100
4	100
5	100
6	100
7	100
8	100
9	100
10	100
11	100
12	100
13	100
14	100
15	100
16	100
17	100
18	100
19	100
20	100
21	100
22	100
23	100
24	100
25	100
26	100
27	100
28	100
29	100
30	100

Wind in September

Winds average 12 km/h in September.

Across September, daily wind ranges from about 11 km/h on the calmest days to 12 km/h 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 (km/h)	11	11	11	11	11	11	11	11	11	11	11	12	12	12	12	12	12	12	12	12	12	12	12	12	12	12	12	12	12	12
Feels	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm

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

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 6:34 AM to 7:12 AM, and sunset from 7:43 PM to 6:44 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	13.0	13.0	12.9	12.9	12.8	12.8	12.7	12.7	12.6	12.5	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)	6:34	6:35	6:37	6:38	6:39	6:40	6:42	6:43	6:44	6:46	6:47	6:48	6:50	6:51	6:52	6:54	6:55	6:56	6:57	6:59	7:00	7:01	7:03	7:04	7:05	7:07	7:08	7:09	7:11	7:12
Sunset (PM)	7:43	7:41	7:39	7:37	7:35	7:33	7:31	7:29	7:27	7:25	7:23	7:21	7:19	7:17	7:15	7:13	7:11	7:09	7:07	7:05	7:03	7:01	6:59	6:56	6:54	6:52	6:50	6:48	6:46	6:44

	Daylight (h)	Sunrise (AM)	Sunset (PM)
1	13.2	6:34	7:43
2	13.1	6:35	7:41
3	13.0	6:37	7:39
4	13.0	6:38	7:37
5	12.9	6:39	7:35
6	12.9	6:40	7:33
7	12.8	6:42	7:31
8	12.8	6:43	7:29
9	12.7	6:44	7:27
10	12.7	6:46	7:25
11	12.6	6:47	7:23
12	12.5	6:48	7:21
13	12.5	6:50	7:19
14	12.4	6:51	7:17
15	12.4	6:52	7:15
16	12.3	6:54	7:13
17	12.3	6:55	7:11
18	12.2	6:56	7:09
19	12.2	6:57	7:07
20	12.1	6:59	7:05
21	12.0	7:00	7:03
22	12.0	7:01	7:01
23	11.9	7:03	6:59
24	11.9	7:04	6:56
25	11.8	7:05	6:54
26	11.8	7:07	6:52
27	11.7	7:08	6:50
28	11.6	7:09	6:48
29	11.6	7:11	6:46
30	11.5	7:12	6:44

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 4.74 kWh/m².

For context, solar energy here swings from a low near 1.71 kWh/m² to a high of 6.65 kWh/m² in June across the year — September's 4.74 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)	5.2	5.2	5.2	5.1	5.1	5.0	5.0	5.0	5.0	4.9	4.9	4.9	4.8	4.8	4.8	4.8	4.7	4.7	4.7	4.6	4.6	4.5	4.5	4.5	4.4	4.4	4.3	4.3	4.2	4.2
Level	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright

	Solar energy (kWh/m²)	Level
1	5.2	Bright
2	5.2	Bright
3	5.2	Bright
4	5.1	Bright
5	5.1	Bright
6	5.0	Bright
7	5.0	Bright
8	5.0	Bright
9	5.0	Bright
10	4.9	Bright
11	4.9	Bright
12	4.9	Bright
13	4.8	Bright
14	4.8	Bright
15	4.8	Bright
16	4.8	Bright
17	4.7	Bright
18	4.7	Bright
19	4.7	Bright
20	4.6	Bright
21	4.6	Bright
22	4.5	Bright
23	4.5	Bright
24	4.5	Bright
25	4.4	Bright
26	4.4	Bright
27	4.3	Bright
28	4.3	Bright
29	4.2	Bright
30	4.2	Bright

Planning a trip in September

Is September a good time to visit Arvayheer?

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

5.6

Sightseeing

4th-best month of the year

1.0

Beach & pool

4th-best month of the year

September is a reasonable time to visit Arvayheer for sightseeing.

What to pack for Arvayheer in September

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

In September, Arvayheer sees daytime highs around 16°C and nights near 3°C. Worth packing: a warm layer and sun protection. About 5 days see rain.

a warm layersun protection

UV index in Arvayheer in September

LowModerateHighVery highExtreme

Clear-sky midday UV in September peaks around 6 — enough to warrant sun protection. The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Arvayheer peaks around July 19 at about 9 (very high) — sunscreen, a hat and midday shade are essential. It bottoms out near January 10 at about 1 (low).

The index reaches 3 or more — the level where the WHO recommends sun protection — in 7 months of the year.

	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
UV index (midday)	1	2	3	7	7	8	9	8	6	3	1	1
Level	Low	Moderate	Moderate	High	Very high	Very high	Very high	Very high	High	Moderate	Low	Low

	UV index (midday)	Level
Jan	1	Low
Feb	2	Moderate
Mar	3	Moderate
Apr	7	High
May	7	Very high
Jun	8	Very high
Jul	9	Very high
Aug	8	Very high
Sep	6	High
Oct	3	Moderate
Nov	1	Low
Dec	1	Low

Air quality in Arvayheer 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 Arvayheer is worst in June — around 16 µg/m³ PM2.5 (moderate), about 6.2× the cleanest month (December, 3 µg/m³).

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

	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
PM2.5 (µg/m³)	6	7	11	11	13	16	16	16	9	7	6	3
Level	Good	Good	Good	Good	Moderate	Moderate	Moderate	Moderate	Good	Good	Good	Good

	PM2.5 (µg/m³)	Level
Jan	6	Good
Feb	7	Good
Mar	11	Good
Apr	11	Good
May	13	Moderate
Jun	16	Moderate
Jul	16	Moderate
Aug	16	Moderate
Sep	9	Good
Oct	7	Good
Nov	6	Good
Dec	3	Good

Location & terrain

Where is Arvayheer?

Arvayheer sits at 46.3°N, 102.8°E, 1,838 m above sea level, in Mongolia. The nearest listed city is Bayanhongor, 158 km away.

Topography around Arvayheer

How much the land rises and falls, and what covers it, within 3, 16 and 80 km of Arvayheer.

Within 3 km, the terrain around Arvayheer has only modest variations in elevation — a maximum elevation change of 231 m around an average of 1,849 m above sea level; within 16 km, large variations in elevation — a maximum elevation change of 748 m; within 80 km, very significant variations in elevation — a maximum elevation change of 1,823 m.

The land around Arvayheer is covered by grassland (77%) within 3 km, grassland (98%) within 16 km, and grassland (89%) within 80 km.

3 km

231 m

grassland 77%

16 km

748 m

grassland 98%

80 km

1,823 m

grassland 89%

treesgrasslandartificial surfacesbare terrainmoss and lichen

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

September weather nearby: Bayanhongor 158 km · Tsetserleg 168 km · Hovd 180 km · Bogd 183 km · Bulgan 289 km · Erdenet 323 km · Dalandzadgad 326 km · Dzuunmod 355 km

Mongolia travel facts

Travel advisory: Level 1; Exercise Normal Precautions
Power plugs: Type C / E / F; 220 V · 50 Hz
Prices: ≈ 34% of US; price level, 2025
GDP per capita: $7,108; 2025
Happiness: 5.9 / 10; World Happiness, 2025
Safe drinking water: 43%; of population, 2024
Homicide rate: 5.9; per 100k, 2023
Road deaths: 21; per 100k/yr, 2019
Income group: Upper middle; World Bank
English: Very low; EF EPI 447
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 Arvayheer (46.2639°, 102.775°, elevation 1,838 m), 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).

	Avg high (°C)	Avg low (°C)
1	19	7
2	19	7
3	19	6
4	18	6
5	18	6
6	18	6
7	18	5
8	17	5
9	17	5
10	17	4
11	17	4
12	17	4
13	16	4
14	16	3
15	16	3
16	16	3
17	16	3
18	15	2
19	15	2
20	15	2
21	15	2
22	15	1
23	14	1
24	14	1
25	14	0
26	14	0
27	13	0
28	13	0
29	13	-1
30	12	-1

	Clearer (%)	Cloudier (%)
1	58	42
2	58	42
3	59	41
4	59	41
5	60	40
6	61	39
7	62	38
8	62	38
9	64	36
10	65	35
11	66	34
12	67	33
13	68	32
14	70	30
15	70	30
16	71	29
17	73	27
18	73	27
19	73	27
20	74	26
21	74	26
22	74	26
23	74	26
24	75	25
25	74	26
26	74	26
27	74	26
28	75	25
29	75	25
30	74	26

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

	Dry (%)
1	100
2	100
3	100
4	100
5	100
6	100
7	100
8	100
9	100
10	100
11	100
12	100
13	100
14	100
15	100
16	100
17	100
18	100
19	100
20	100
21	100
22	100
23	100
24	100
25	100
26	100
27	100
28	100
29	100
30	100

	Avg high (°C)	Avg low (°C)
1	19	7
2	19	7
3	19	6
4	18	6
5	18	6
6	18	6
7	18	5
8	17	5
9	17	5
10	17	4
11	17	4
12	17	4
13	16	4
14	16	3
15	16	3
16	16	3
17	16	3
18	15	2
19	15	2
20	15	2
21	15	2
22	15	1
23	14	1
24	14	1
25	14	0
26	14	0
27	13	0
28	13	0
29	13	-1
30	12	-1

	Clearer (%)	Cloudier (%)
1	58	42
2	58	42
3	59	41
4	59	41
5	60	40
6	61	39
7	62	38
8	62	38
9	64	36
10	65	35
11	66	34
12	67	33
13	68	32
14	70	30
15	70	30
16	71	29
17	73	27
18	73	27
19	73	27
20	74	26
21	74	26
22	74	26
23	74	26
24	75	25
25	74	26
26	74	26
27	74	26
28	75	25
29	75	25
30	74	26

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

	Dry (%)
1	100
2	100
3	100
4	100
5	100
6	100
7	100
8	100
9	100
10	100
11	100
12	100
13	100
14	100
15	100
16	100
17	100
18	100
19	100
20	100
21	100
22	100
23	100
24	100
25	100
26	100
27	100
28	100
29	100
30	100

	Avg high (°C)	Avg low (°C)
1	19	7
2	19	7
3	19	6
4	18	6
5	18	6
6	18	6
7	18	5
8	17	5
9	17	5
10	17	4
11	17	4
12	17	4
13	16	4
14	16	3
15	16	3
16	16	3
17	16	3
18	15	2
19	15	2
20	15	2
21	15	2
22	15	1
23	14	1
24	14	1
25	14	0
26	14	0
27	13	0
28	13	0
29	13	-1
30	12	-1

	Clearer (%)	Cloudier (%)
1	58	42
2	58	42
3	59	41
4	59	41
5	60	40
6	61	39
7	62	38
8	62	38
9	64	36
10	65	35
11	66	34
12	67	33
13	68	32
14	70	30
15	70	30
16	71	29
17	73	27
18	73	27
19	73	27
20	74	26
21	74	26
22	74	26
23	74	26
24	75	25
25	74	26
26	74	26
27	74	26
28	75	25
29	75	25
30	74	26

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

	Dry (%)
1	100
2	100
3	100
4	100
5	100
6	100
7	100
8	100
9	100
10	100
11	100
12	100
13	100
14	100
15	100
16	100
17	100
18	100
19	100
20	100
21	100
22	100
23	100
24	100
25	100
26	100
27	100
28	100
29	100
30	100