Mongolia Ulaanbaatar Weather in September — Climate Guide
September in Ulaanbaatar is high
Ulaanbaatar Weather in September — Quick Answer
As of 2026- Avg temp
- 16° / 4°
- Rainfall
- 23mm · 7 days
- Crowds
- Moderate
As of 2026, Ulaanbaatar in September averages a high of 16°C and low of 4°C with 23mm of rain over about 7 days. Crisp early autumn — pleasant days near 16°C, chilly nights around 4°C. Layers are essential: T-shirt or shirt by day, warm jacket and fleece for cold evenings on the steppe. Drier than summer, but a light rain layer is still wise.
September is high for Ulaanbaatar.
September is a quietly excellent month and arguably the best for travelers who want good weather without summer crowds. Days are still pleasant around 16°C, the summer rains taper off, and the light turns golden as the steppe and the larch forests of Terelj take on autumn colors.
Nights get cold quickly, dropping to around 4°C, so a warm layer is essential even on sunny days — and by late September a frost is possible. Ger camps are still operating but starting to wind down toward month's end.
Travel score
Ulaanbaatar September Weather Stats
Avg High
16°C
Avg Low
4°C
Rainy Days
7
23mm total
Sunshine
9h
Daily avg
Humidity
50%
comfortable and dry
UV Index
5
Moderate
Wind
10 km/h
Gusts 28
Crowds
Moderate
At attractions
September Sunrise & Sunset
Air Quality
PM2.5
16 μg/m³
PM10
55 μg/m³
Status
good
Feels-Like Temperature & Wind
Feels like
Daytime
15°C
Nighttime
1°C
Humidity and wind affect how the actual temperature feels.
Wind
10 km/h
Max gust 28 km/h
Activities Recommended for September
September Travel Pros & Cons
Pros
- Autumn colors on steppe and in Terelj
- Drier, clearer than summer
- Fewer crowds, prices easing
- Comfortable days (~16°C)
Cons
- Cold nights (around 4°C), early frosts late month
- Ger camps winding down by late Sept
- Daylight shortening
- Sharp day-to-night temperature swings
September Events & Festivals
- Autumn colors arrive on the steppe and in Terelj
- Rains ease; clearer, drier days
- Shoulder season — fewer crowds, lower prices
Ulaanbaatar in September — Full Picture
September is a quietly excellent month and arguably the best for travelers who want good weather without summer crowds. Days are still pleasant around 16°C, the summer rains taper off, and the light turns golden as the steppe and the larch forests of Terelj take on autumn colors.
Nights get cold quickly, dropping to around 4°C, so a warm layer is essential even on sunny days — and by late September a frost is possible. Ger camps are still operating but starting to wind down toward month's end.
With fewer tourists and prices easing from the summer peak, September rewards travelers who don't mind cool evenings. It's a strong choice for photography, horse trekking, and a final-window Gobi trip before the cold sets in. Aim for early-to-mid September before camps begin closing.
What to Wear & What to Pack
Crisp early autumn — pleasant days near 16°C, chilly nights around 4°C. Layers are essential: T-shirt or shirt by day, warm jacket and fleece for cold evenings on the steppe. Drier than summer, but a light rain layer is still wise.
Packing Checklist
Seasonal Weather Overview
Spring (Mar·Apr·May)
7.7°C
-5°C
4.3/mo
Summer (Jun·Jul·Aug)
22.3°C
10.7°C
11.3/mo
Autumn (Sep·Oct·Nov)
Current6.3°C
-5.7°C
4.7/mo
Winter (Dec·Jan·Feb)
-13.3°C
-23.7°C
2/mo
Ulaanbaatar Monthly Weather Comparison
| Month | High | Low | Rain | Sun | Humid | UV | Crowd | Price |
|---|---|---|---|---|---|---|---|---|
| -16° | -26° | 2d·2mm | 5.5h | 70% | 1 | Quiet | Low season | |
| -11° | -22° | 2d·2mm | 7h | 68% | 2 | Quiet | Low season | |
| -1° | -13° | 3d·3mm | 8h | 55% | 3 | Quiet | Low season | |
| 8° | -4° | 4d·7mm | 8.5h | 45% | 4 | Quiet | Low season | |
| 16° | 2° | 6d·16mm | 9.5h | 45% | 6 | Moderate | Shoulder | |
| June (Best) | 21° | 8° | 9d·40mm | 10h | 50% | 7 | Busy | Peak |
| July (Best) | 24° | 13° | 12d·65mm | 9.5h | 55% | 8 | Very busy | Peak |
| August (Best) | 22° | 11° | 13d·70mm | 9h | 58% | 7 | Busy | Peak |
| 16° | 4° | 7d·23mm | 9h | 50% | 5 | Moderate | Shoulder | |
| 7° | -5° | 4d·6mm | 7.5h | 50% | 3 | Quiet | Low season | |
| -4° | -16° | 3d·4mm | 6h | 60% | 2 | Quiet | Low season | |
| -13° | -23° | 2d·2mm | 5h | 68% | 1 | Quiet | Low season |
View Other Months
Ulaanbaatar September Hotel Picks
Frequently Asked Questions
Is September a good time to visit Ulaanbaatar?
Ulaanbaatar in September is high. Tourist crowds are moderate and flight/hotel prices are shoulder.
What's the average temperature in Ulaanbaatar in September?
Ulaanbaatar September averages a high of 16°C and a low of 4°C.
Does it rain much in Ulaanbaatar in September?
Ulaanbaatar September averages 23mm of rainfall over about 7 rainy days.
What should I wear in Ulaanbaatar in September?
Crisp early autumn — pleasant days near 16°C, chilly nights around 4°C. Layers are essential: T-shirt or shirt by day, warm jacket and fleece for cold evenings on the steppe. Drier than summer, but a light rain layer is still wise.
What time are sunrise and sunset in Ulaanbaatar in September?
Ulaanbaatar September sunrise is 06:25 and sunset is 18:50, with 12h 25min of daylight.
What's the air quality like in Ulaanbaatar in September?
Ulaanbaatar September air quality (AQI) averages 42, rated Good. PM2.5 averages 16μg/m³.
What activities are recommended in Ulaanbaatar in September?
In September, Ulaanbaatar is great for Terelj ger stay (autumn colors), Horse trekking, Hustai National Park.
Is September peak season in Ulaanbaatar?
Ulaanbaatar September crowds are moderate and prices are shoulder. You can travel relatively comfortably without long queues.
Best Months to Visit Ulaanbaatar
View Other Months
Planning a September trip to Ulaanbaatar?
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Why you can trust weather guide
Based in Chiang Mai for 8+ years, with 30+ countries visited across Southeast Asia, Japan, and Europe. Every detail in this guide is primary-source verified as of April 2026, with prices auto-refreshed via live exchange rate APIs. This isn't AI-generated boilerplate — it's written from the perspective of someone who has actually been there.