December is one of the cooler months of the year in Upper Siang, with average highs near 15.9°C and lows around 4.7°C (mean 10.3°C). It is one of the drier months, averaging 9 mm of rainfall and 74% relative humidity across the period.
December is one of the cooler months of the year in Upper Siang. Across 45 years of records, the warmest December in Upper Siang was 2017 — when the month averaged 12.6°C — while the coldest were 1982 and 1983 at 8.7°C. Typical December days reach 15.9°C with nights near 4.7°C. The long-term trend is warming, about 0.3°C per decade.
December is one of the drier months in Upper Siang, averaging 9 mm of rainfall. The wettest December on record was 1985 with 61 mm, while the driest were 1994, 1996 and 2005 at 0 mm.
Relative humidity in Upper Siang during December averages 74%. The most humid Decembers were 2012 and 2022 at 81%, and the least humid was 1998 at 60%.
December receives about 3.3 kWh/m²/day of solar energy in Upper Siang. The sunniest December was 2005 at 3.9 kWh/m²/day, and the cloudiest was 2009 at 2.7.
Average wind speed in Upper Siang during December is 0.5 m/s. The windiest Decembers were 2000, 2001 and 2005, among others at 0.6 m/s, while the calmest were 2019, 2020 and 2022, among others at 0.4 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 9.7°C | 10.0°C | 10.4°C | 10.8°C | 10.7°C | +1°C |
| Avg High | 15.5°C | 16.1°C | 16.2°C | 15.8°C | 15.7°C | +0.2°C |
| Avg Low | 3.9°C | 3.9°C | 4.5°C | 5.7°C | 5.7°C | +1.8°C |
| Avg Rain | 18 mm | 7 mm | 4 mm | 7 mm | 11 mm | -7 mm |
December temperatures in Upper Siang have risen by about 1.7°C between 1981–1985 and 2021–2025.
December has ranged from a record low of -1.3°C (1986) to a record high of 26.4°C (2016).
Rainfall in December is one of the drier months, averaging 9 mm, with a wettest year of 61 mm.
Daytime highs and overnight lows have shifted differently — highs rose about 0.1°C per decade while lows rose 0.6°C per decade, narrowing the gap between day and night.
A quieter season to visit Upper Siang
If your dates are flexible, the more temperate months of October and May tend to be the most comfortable for visiting Upper Siang. That said, December — with days averaging 15.9°C and nights around 4.7°C (mean 10.3°C) and low rainfall (9 mm) — can still be rewarding for travellers who don't mind the cooler conditions, and often means fewer crowds.
| Year | Avg High | Avg Temp | Avg Low | Hottest Day | Coldest Day | Rainfall | Humidity | Wind | Solar |
|---|---|---|---|---|---|---|---|---|---|
| 2025 | 16.6°C | 11.4°C | 6.1°C | 22.5°C | 3.8°C | 5 mm | 75% | 0.5 m/s | — |
| 2024 | 15.4°C | 10.3°C | 5.1°C | 17.8°C | 2.4°C | 1 mm | 74% | 0.5 m/s | 3.4 |
| 2023 | 16.5°C | 11.4°C | 6.3°C | 21.5°C | 2.9°C | 12 mm | 77% | 0.5 m/s | 3.2 |
| 2022 | 15.4°C | 10.5°C | 5.6°C | 19.0°C | 1.2°C | 24 mm | 81% | 0.4 m/s | 2.8 |
| 2021 | 15.5°C | 10.6°C | 5.7°C | 20.0°C | 1.3°C | 13 mm | 78% | 0.5 m/s | 3.2 |
| 2020 | 14.7°C | 10.1°C | 5.5°C | 18.0°C | 3.0°C | 11 mm | 81% | 0.4 m/s | 3.2 |
| 2019 | 14.8°C | 10.0°C | 5.3°C | 20.1°C | 0.3°C | 3 mm | 78% | 0.4 m/s | 3 |
| 2018 | 15.8°C | 10.6°C | 5.3°C | 20.2°C | 1.8°C | 14 mm | 75% | 0.5 m/s | 3.4 |
| 2017 🔥 | 17.6°C | 12.6°C | 7.5°C | 20.9°C | 3.3°C | 1 mm | 79% | 0.5 m/s | 3.6 |
| 2016 | 17.8°C | 12.5°C | 7.3°C | 26.4°C | 3.5°C | 7 mm | 74% | 0.5 m/s | 3.5 |
| 2015 | 14.2°C | 9.5°C | 4.9°C | 18.5°C | 1.0°C | 12 mm | 81% | 0.4 m/s | 2.8 |
| 2014 | 16.4°C | 11.6°C | 6.8°C | 22.6°C | 2.7°C | 1 mm | 78% | 0.4 m/s | 3.1 |
| 2013 | 14.6°C | 9.7°C | 4.8°C | 23.3°C | 0.4°C | 5 mm | 78% | 0.4 m/s | 3 |
| 2012 | 15.4°C | 10.9°C | 6.4°C | 19.1°C | 2.9°C | 10 mm | 81% | 0.4 m/s | 3 |
| 2011 | 15.6°C | 10.2°C | 4.7°C | 23.0°C | 1.7°C | 17 mm | 76% | 0.5 m/s | 3.2 |
| 2010 | 16.2°C | 10.1°C | 3.9°C | 21.6°C | 1.2°C | 3 mm | 70% | 0.5 m/s | 3.7 |
| 2009 | 14.5°C | 9.5°C | 4.4°C | 20.5°C | 1.7°C | 6 mm | 79% | 0.5 m/s | 2.7 |
| 2008 | 16.7°C | 11.1°C | 5.5°C | 24.3°C | 1.7°C | 2 mm | 76% | 0.5 m/s | 3.2 |
| 2007 | 16.2°C | 10.3°C | 4.4°C | 21.3°C | 1.2°C | 4 mm | 68% | 0.5 m/s | 3.4 |
| 2006 | 16.1°C | 10.4°C | 4.7°C | 20.3°C | 3.2°C | 9 mm | 74% | 0.5 m/s | 3.2 |
| 2005 | 17.2°C | 10.9°C | 4.7°C | 22.0°C | 3.0°C | 0 mm | 68% | 0.6 m/s | 3.9 |
| 2004 | 15.6°C | 10.0°C | 4.3°C | 24.3°C | 1.3°C | 10 mm | 74% | 0.5 m/s | 3.3 |
| 2003 | 16.1°C | 10.2°C | 4.3°C | 22.8°C | 1.6°C | 2 mm | 71% | 0.5 m/s | 3.3 |
| 2002 | 15.7°C | 10.1°C | 4.6°C | 21.8°C | 2.6°C | 2 mm | 72% | 0.5 m/s | 3.3 |
| 2001 | 16.9°C | 10.5°C | 4.1°C | 21.7°C | 1.4°C | 4 mm | 66% | 0.6 m/s | 3.4 |
| 2000 | 17.0°C | 10.6°C | 4.1°C | 20.8°C | 2.0°C | 2 mm | 63% | 0.6 m/s | 3.6 |
| 1999 | 16.2°C | 10.3°C | 4.3°C | 19.4°C | 1.7°C | 1 mm | 70% | 0.5 m/s | 3.6 |
| 1998 | 17.9°C | 11.2°C | 4.5°C | 24.2°C | 1.2°C | 4 mm | 60% | 0.6 m/s | 3.7 |
| 1997 | 15.3°C | 9.5°C | 3.8°C | 20.1°C | 1.0°C | 17 mm | 74% | 0.5 m/s | 3.1 |
| 1996 | 17.1°C | 10.4°C | 3.6°C | 22.3°C | 1.8°C | 0 mm | 67% | 0.6 m/s | 3.8 |
| 1995 | 14.7°C | 9.2°C | 3.7°C | 19.3°C | 0.8°C | 15 mm | 80% | 0.4 m/s | 2.9 |
| 1994 | 16.3°C | 9.8°C | 3.2°C | 23.8°C | 0.4°C | 0 mm | 66% | 0.6 m/s | 3.5 |
| 1993 | 16.9°C | 10.7°C | 4.6°C | 25.1°C | 2.4°C | 0 mm | 70% | 0.6 m/s | 3.4 |
| 1992 | 14.8°C | 8.9°C | 3.0°C | 19.5°C | 0.7°C | 2 mm | 70% | 0.6 m/s | 3.7 |
| 1991 | 15.7°C | 9.9°C | 4.1°C | 26.2°C | 0.7°C | 30 mm | 72% | 0.5 m/s | 3.3 |
| 1990 | 16.4°C | 10.4°C | 4.4°C | 21.7°C | 2.2°C | 0 mm | 77% | 0.5 m/s | 3.4 |
| 1989 | 16.0°C | 9.5°C | 2.9°C | 26.1°C | 0.0°C | 9 mm | 69% | 0.5 m/s | 3.6 |
| 1988 | 16.9°C | 11.2°C | 5.5°C | 24.8°C | 2.5°C | 6 mm | 76% | 0.5 m/s | 3.5 |
| 1987 | 17.4°C | 11.5°C | 5.5°C | 23.6°C | 2.4°C | 11 mm | 68% | 0.5 m/s | 3.7 |
| 1986 | 15.9°C | 9.6°C | 3.4°C | 21.9°C | -1.3°C | 9 mm | 70% | 0.5 m/s | 3.3 |
| 1985 🌧️ | 15.1°C | 9.5°C | 3.8°C | 17.9°C | 0.8°C | 61 mm | 77% | 0.5 m/s | 3.3 |
| 1984 | 14.6°C | 9.0°C | 3.3°C | 22.5°C | 1.7°C | 15 mm | 74% | 0.5 m/s | 3.2 |
| 1983 | 14.4°C | 8.7°C | 3.0°C | 20.9°C | 0.9°C | 22 mm | 74% | 0.5 m/s | — |
| 1982 ❄️ | 13.8°C | 8.7°C | 3.7°C | 16.5°C | 0.8°C | 7 mm | 77% | 0.4 m/s | — |
| 1981 | 15.5°C | 9.8°C | 4.1°C | 19.4°C | 1.6°C | 20 mm | 78% | 0.5 m/s | — |
Actual recorded December data for each year, 1981–2025 — sourced from NASA POWER.
The average high in December is around 15.9°C with lows near 4.7°C (mean 10.3°C), based on 45 years of NASA POWER data.
December averages 9 mm of rainfall in Upper Siang, one of the drier months. The wettest on record was 61 mm in 1985.
The hottest December reached 26.4°C in 2016. The coldest dipped to -1.3°C in 1986.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average December temperatures have risen by about 1.7°C. Daytime highs moved from 14.7°C to 15.9°C and overnight lows from 3.6°C to 5.8°C over the same span.
December is one of the cooler months of the year in Upper Siang and one of the drier months, so plan for around 15.9°C daytime highs and 4.7°C at night.
Not quite — December is the 2nd coolest month in Upper Siang, averaging 10.3°C.
For December in Upper Siang, pack warm layers and a jacket for chilly mornings, with typical highs of 15.9°C and lows of 4.7°C.
Relative humidity in December averages 74% — moderately humid.
Average wind speed in December is 0.5 m/s. The windiest December on record averaged 0.6 m/s (1992).
The wettest December on record was 1985 with 61 mm. On average, December sees 9 mm.
All figures are derived from NASA POWER (Prediction Of Worldwide Energy Resources), based on MERRA-2 satellite reanalysis, covering 1981–2025.
Explore how the weather in Upper Siang behaves each December, based on 45 years of NASA POWER climate data from 1981 to 2025. This page breaks down average temperatures, rainfall, humidity, wind and solar radiation for December specifically, along with year-by-year records and how the month has changed over the decades.
