About 0.7°F per decade, measured from Arvayheer's official daily weather records, 1971–2025. Individual years still bounce around — some recent ones came in cool — but the long-term line has clearly risen.
Is that a lot? Arvayheer's warming is broadly in line with other cities in Mongolia — neither unusually fast nor unusually slow.
What has actually changed
Each card compares the 1970s (the first ten years of the
record) with recent years (the last ten) — the same span
the headline and the chart use.
Freezing nights
77 fewer nights
1970s
218 / yr
→
Recent
141 / yr
Milder winters — fewer frosts
Average temperature
+2.7°F
1970s
33.8°F
→
Recent
36.5°F
A steady upward drift
Hot days above 90°F
1 more day
1970s
0 / yr
→
Recent
1 / yr
More days of serious heat
Rainy days
17 fewer days
1970s
37 / yr
→
Recent
20 / yr
Drier on average
Arvayheer's temperature, year by year
Average temperature for each year from 1971 to 2025.
a warmer-than-average year a cooler-than-average year
Each bar is one year. Most recent years sit above the older ones.
Some recent years still came in cool — warming is a slope,
not a straight climb.
In day-to-day terms, that long-term shift shows up as about 53 fewer freezing nights a year compared with the 1970s.
When in the year the change shows up
How much warmer each month is now than in the 1970s.
Useful if you garden or care about a particular season —
otherwise the headline above already has the answer.
March has warmed the most — about 2.7°F. The warming runs across the whole year, not just one season.
Methodology & sources
Temperature — 1991–2020 normals computed from 29 years of daily observations at Arvaiheer, a weather station, inside the city. The underlying daily records come from NOAA's global station network.