Mongolia in September: Weather, Crowds & What to Expect
Climate Map for September
Average temperature across Mongolia in September.
City Weather in September
| City | High | Low | Rain | UV | Feels |
|---|---|---|---|---|---|
| Ulaanbaatar | 16° | 1° | 33 mm | high | Cold |
| Erdenet | 15° | 0° | 41 mm | moderate | Cold |
| Darkhan (city) | 17° | 2° | 37 mm | moderate | Cold |
| Choibalsan (city) | 18° | 5° | 31 mm | moderate | Cool |
| Bayankhongor | 15° | 2° | 21 mm | high | Cold |
| Ulaangom | 17° | 3° | 14 mm | moderate | Cool |
| Khovd (city) | 18° | 4° | 11 mm | high | Cool |
High / low are average daily temperatures (°C). “Feels” reflects how hot or cold it feels, allowing for humidity.
Ulaanbaatar and the Central Highlands
Autumn’s arrival in September turns the grassland to brown and the highland larch and birch show yellowing that’s lovely around Terelj and Karakorum. Daytime temperatures drop into the single digits to low teens and nights are crisp; it’s an ideal month for photography, hiking without insects, and quiet ger-camp stays. Some roads become easier as dust settles, but early frost at higher elevations can surprise overnight campers.
The Gobi Desert and Southern Sands (Dalanzadgad, Khongoryn Els, Bayanzag)
By September the Gobi cools noticeably, offering the most pleasant conditions for walking and 4x4 exploration-days usually sit between 15-25°C and nights are crisp. The tourist pressure drops after summer, giving you quieter dune camps and easier access to paleontological sites. Beware early frosts at higher-altitude passes and bring a mid-layer for dawn and dusk photography on the Flaming Cliffs.
Western Mongolia and the Altai Mountains (Bayan-Ölgii, Khovd, Altai Tavan Bogd)
September’s clear skies and cooling temperatures make it a favorite for photographers: larch and aspen begin to turn gold and days are crisp, often between 5-15°C. The Golden Eagle Festival is commonly scheduled around this time in Bayan-Ölgii, bringing spectacle and crowds to the region, so plan travel and accommodation early. Nights grow cold quickly, so pack warm sleeping gear and a good down jacket.
Lake Khövsgöl and Northern Taiga (Khatgal, Murun, Khovsgol National Park)
September paints the larch forests gold and drops temperatures into a crisp range (5-12°C) with frost possible at night-this is peak autumn colour and a favorite for photographers. Tourist numbers fall away and trails feel quiet; some boat operators cease runs as the season winds down, so confirm schedules. Nights get cold quickly, so insulated sleeping gear and a warm jacket are essential.
Eastern Steppe and Dornod Grasslands (Choibalsan, Onon River, Mongol Daguur)
September cools rapidly and the steppe begins to show autumn tones; daytime highs drop into the low teens and nights can be frosty. Migration movements are visible again as birds prepare for flight, and tourist numbers taper off-this is a peaceful month for birdwatching and homestay visits. Prepare for large temperature swings between day and night and for shorter daylight hours.