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Ulan Bator weather by month: averages, rainfall & climate trends

Ulan Bator swings through a wide annual range, with 38.9°C between the monthly means of its warmest and coldest months. Rainfall is on the low side overall. Ulan Bator weather by month: average temperatures, rainfall, records and how the climate has changed since 1940.

Today vs average

−2.0°Chigh below average

5° / −4°Today
7° / −5°Average
see today in detail →

How it's changed

+1.0°Caverage temperature, 2016–2025 vs 1940–1949average temperature vs 1940–49211frost days a year now (2016–2025) · 218 in the 1940sfrost days a year · 218 in the 1940s5days above 30°C a year now (2016–2025) · 3 in the 1940sdays above 30°C · 3 in the 1940s+1.0°C vs the 1940s · see how it's changed →
Weather by montha typical year, averaged over the full recordJanuary, rain 4 mmhigh −15°low −27°February, rain 6 mmhigh −11°low −25°March, rain 12 mmhigh −2°low −16°April, rain 23 mmhigh 8°low −5°May, rain 38 mmhigh 15°low 3°June, rain 64 mmhigh 21°low 9°July, rain 86 mmhigh 23°low 12°August, rain 80 mmhigh 21°low 10°September, rain 44 mmhigh 15°low 3°October, rain 19 mmhigh 6°low −6°November, rain 10 mmhigh −6°low −17°December, rain 5 mmhigh −14°low −25°wettest month July, 86 mm · 390 mm a yearsee month by month →

Right now

What it's doing today vs the historical average for this date.
Mostly clear

Right now

4.5°

−1°feels like
39%humidity
−8°dew point
18 km/hfrom NW
UV index1.4
sunrise07:07sunset18:11day length11h 04m
TodayPartly cloudy5°−4°
TueClear9°−5°
WedOvercast7°−5°
ThuOvercast6°−3°
FriOvercast4°−2°
SatLight snow−1°−5°
SunPartly cloudy−4°−7°

On this date: October 12

Today (forecast)
5° / −4°
Average for October 12
7° / −5°

High below average · −2.0°C

  • Record high: 19.6° · 1957
  • Record low: −14.8° · 1941
  • One year ago: 4° / −3°

Every October 12 in history, coldest to hottest

▲ Daily highs▼ Daily lows

Dots show daily highs (top) and lows (bottom) for each October 12 on record (n = 87). Outlined dots are today's forecast.

Area we sample

Each city's history comes from one ERA5 grid cell, about 28 km across, shown by the dashed box. Near mountains or coasts, conditions can vary across the cell.

Location & data

Historical weather for Ulan Bator is sampled from the ECMWF ERA5 reanalysis at 47.91°N, 106.88°E, with daily records since 1940.

Coordinates
47.91°N, 106.88°E
Time zone
Asia/Ulaanbaatar
Period
1940–2026
Data source
ERA5 (ECMWF)

Last 30 days

22 of the last 31 days were warmer than the historical average for that date. Average difference: +1.5°C.

Each bar is one day, from morning low to afternoon high. Warm-colored bars are days whose mean ran above average; cool bars ran below. The dot inside the bar is the daily mean. The shaded band is the typical 10–90% range expected for that date. Average = the day's mean temperature averaged across every year of record (1940–2026) for that calendar date.

This date over the years

One dot per year, showing the mean temperature on this calendar date. Dots are warmer or cooler than the long-term average (dashed line); the shaded band is the typical 10–90% range, and the highlighted dot is today's forecast. Based on ERA5 reanalysis: modelled estimates, not station readings.

Weather by month

Average temperatures and rainfall for each month: a typical year, from the full record.

Climate overview

The warmest month is July, with typical afternoon highs of 22.8°C and nights around 12.4°C. At the other extreme, January brings afternoon highs of about −15.0°C and typical overnight lows of −27.5°C. Frost shows up on around 210 mornings a year.

The yearly total for Ulan Bator comes to about 390 mm; monthly amounts range from 4 mm in January up to 86 mm in July.

The record here starts in 1940, and since then the annual mean in Ulan Bator has climbed 1.0°C from the first ten years to the last ten. Recent years have brought less rain as well. The last decade sits roughly 10% under the long-term average.

Climate graph (climograph)

July is the warmest month, January the coolest: a yearly swing of 39°C. Wettest month: July (~86 mm). Whole year averages ~390 mm of rain.

Bars = average monthly rainfall (right axis). Lines = average daily high and low (left axis). Average = each month's value averaged across every year of record (1940–2026).

Rainy days by month

About 48 rainy days a year: most in July (~10), fewest in January (almost none).

Bars = average number of days with ≥ 2 mm per month. Hover for the monthly rainfall total.

Monthly wind

Average daily peak wind at 10 m, by month.

Monthly solar energy

Average daily incoming solar energy in megajoules per square metre: the record's own proxy for how sunny the month is.

Ulan Bator month by month: what to expect

Typical conditions for each month, averaged across the full record (since 1940). Daylight is the time from sunrise to sunset. Record high/low are the most extreme values in the ERA5 dataset (modelled since 1940), so they can differ from official weather-station readings.

MonthAvg highAvg lowRainRainy daysDaylightRecord highRecord low
January−15.0°−27.5°4 mm08.6 h−1.7° (1949)−41.4° (1967)
February−10.6°−25.3°6 mm110.0 h8.9° (2007)−43.2° (1969)
March−1.5°−16.2°12 mm211.6 h19.0° (2002)−37.3° (1946)
April7.7°−4.5°23 mm313.4 h27.8° (2020)−28.4° (1971)
May15.2°2.7°38 mm514.9 h32.1° (2017)−16.4° (1958)
June20.9°9.0°64 mm815.8 h35.9° (2010)−4.2° (1961)
July22.8°12.4°86 mm1015.4 h36.9° (1999)1.9° (1988)
August21.0°10.3°80 mm1014.1 h34.8° (2016)−2.1° (1972)
September15.0°3.0°44 mm612.3 h29.6° (2014)−12.6° (1958)
October6.2°−5.7°19 mm310.6 h22.7° (2025)−25.0° (2002)
November−5.6°−17.2°10 mm19.0 h10.5° (2019)−41.8° (1952)
December−13.6°−24.5°5 mm08.2 h3.8° (1989)−40.1° (1947)

How it's changed

Year-by-year signals from 1940 to today.

Climate stripes

Annual mean shifted from 1940–1949 to 2016–2025 by +1.0°C.

Each vertical stripe is one year. Color encodes how much that year's annual mean differed from the long-term average. Average = each year's annual mean compared to the average of all years (1940–2026). cooler ← → warmer

Annual mean temperature

Long-term trend: +0.20°C per decade.

One point per year, showing the temperature averaged across the whole year. The dashed line is the least-squares long-term trend. Based on ERA5 reanalysis: modelled estimates, not station readings.

Seasonal warming

Mar–May is warming fastest: +0.38°C per decade.

Each faint line is one three-month period's average per year; the bold dashed line is its long-term trend. Different parts of the year often warm at different rates. Based on ERA5 reanalysis: modelled estimates, not station readings.

Hot days vs frost days

Days ≥ 30°C per year: 3.1 early in the record → 4.8 recently. Frost days: 218 → 211.

Thin lines are raw yearly counts; thick lines are the smoothed trend that removes year-to-year noise. The hot-day threshold is auto-picked per city so the line actually moves. Average = a centered 5-year rolling average to smooth weather noise.

Yearly hot & cold extremes

All-time high in 1999, all-time low in 1969: 36.9°C / −43.2°C.

One point per year: the single hottest and coldest day recorded that year.

Annual rainfall

~390 mm/year on average. Last decade: −10% vs that average. Long-term trend: −8 mm per decade.

One bar per year of total rainfall. Dashed line is the long-term average. Average = the average annual rainfall across every year of record (1940–2026).

Day-by-day grid

Each tiny square is one calendar day across the full record, about 30,000 days per city. Use the mode switch above the chart: Anomaly colors each day by how far it ran from the historical average for that date (red = warmer, blue = cooler), Daily mean temp shows the absolute mean temperature for the day (useful to see seasons and heatwaves), and Precipitation shows daily rainfall (useful to spot wet/dry seasons and droughts). Average = the long-term average for that calendar date (1940–2026).

Frequently asked questions about Ulan Bator

Which is the warmest month in Ulan Bator?
On long-term average, the warmest month in Ulan Bator is July (mean daily temperature of about 17.7°C) and the coolest is January (about −21.2°C).
How does today's temperature in Ulan Bator compare to the historical average?
On October 12, 2026, Ulan Bator is forecast to reach a high of 5.0°C and a low of −4.3°C. The long-term average for this date (the full record since 1940) is a high of 7.0°C and a low of −4.8°C, so today's high is 2.0°C cooler than that average.
How much has Ulan Bator warmed since 1940?
Comparing the first decade of the record (1940–1949) with the most recent (2016–2025), the annual mean temperature in Ulan Bator is about 1.0°C warmer.
How much does it rain in Ulan Bator?
Ulan Bator receives about 390 mm of precipitation per year on long-term average, with July typically the wettest month.
What is the average temperature in Ulan Bator?
Over the full record (since 1940), the annual mean temperature in Ulan Bator is about −0.7°C. The warmest month is July and the coolest is January.
What are the average temperatures in Ulan Bator by month?
Average daily highs and lows for each month in Ulan Bator (°C, full record since 1940): January −15°/−27°, February −11°/−25°, March −2°/−16°, April 8°/−5°, May 15°/3°, June 21°/9°, July 23°/12°, August 21°/10°, September 15°/3°, October 6°/−6°, November −6°/−17°, December −14°/−25°.
What is the weather like in Ulan Bator in summer?
June to August is summer in Ulan Bator, and it is mild. Daytime highs sit at 21–23°C and nights at 9–12°C; July is the warmest month. Rain is steady at around 77 mm a month, spread over roughly 9 days. It is the wettest season of the year.
What is the weather like in Ulan Bator in winter?
In winter, December through February, Ulan Bator is freezing. Afternoons run −15 to −11°C and nights −27 to −25°C; January is the coldest month. Almost no snow or rain.
What is the weather like in Ulan Bator in spring?
In spring, March through May, Ulan Bator is cold. It warms from −2°C by day and −16°C at night in March to 15°C and 3°C in May. Rain and snow pick up through the season: 12 mm on 2 days in March, 38 mm on 5 days in May.
What is the weather like in Ulan Bator in autumn?
Autumn in Ulan Bator (September to November) is cold. September still brings 15°C afternoons and 3°C nights, November only −6°C and −17°C. Rain and snow fall off from 44 mm on 6 days in September to 10 mm on 1 day in November.
How many days a year does it rain in Ulan Bator?
On long-term average, Ulan Bator has about 48 days a year with at least 2 mm of rain or snow. The annual total is roughly 390 mm.

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