January is one of the cooler months of the year in Thornton, with average highs near 6.1°C and lows around 3.3°C (mean 4.7°C). It is a relatively wet time of year, averaging 112 mm of rainfall and 90% relative humidity across the period.
January is one of the cooler months of the year in Thornton. Across 45 years of records, the warmest January in Thornton was 2007 — when the month averaged 7°C — while the coldest was 1987 at 1.3°C. Typical January days reach 6.1°C with nights near 3.3°C. The long-term trend is warming, about 0.3°C per decade.
January is a relatively wet time of year in Thornton, averaging 112 mm of rainfall. The wettest January on record was 2008 with 206 mm, while the driest was 1997 at 16 mm.
Relative humidity in Thornton during January averages 90%. The most humid Januarys were 1982 and 1997 at 93%, and the least humid was 1984 at 87%.
January receives about 0.7 kWh/m²/day of solar energy in Thornton. The sunniest Januarys were 1985, 1992 and 2001 at 0.8 kWh/m²/day, and the cloudiest were 1984 and 2008 at 0.5.
Average wind speed in Thornton during January is 5.8 m/s. The windiest January was 1983 at 7.9 m/s, while the calmest was 1997 at 3.7 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 3.9°C | 4.6°C | 5.5°C | 4.6°C | 5.2°C | +1.3°C |
| Avg High | 5.3°C | 6.1°C | 6.9°C | 5.9°C | 6.7°C | +1.4°C |
| Avg Low | 2.4°C | 3.1°C | 4.1°C | 3.2°C | 3.8°C | +1.4°C |
| Avg Rain | 108 mm | 112 mm | 116 mm | 106 mm | 122 mm | +14 mm |
January temperatures in Thornton have risen by about 1.3°C between 1981–1985 and 2021–2025.
January has ranged from a record low of -5.5°C (1982) to a record high of 11.7°C (2015).
Rainfall in January is a relatively wet time of year, averaging 112 mm, with a wettest year of 206 mm.
A quieter season to visit Thornton
If your dates are flexible, the more temperate months of July and August tend to be the most comfortable for visiting Thornton. That said, January — with days averaging 6.1°C and nights around 3.3°C (mean 4.7°C) and higher rainfall (112 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 | 5.7°C | 4.2°C | 2.7°C | 10.1°C | -1.5°C | 109 mm | 91% | 4.5 m/s | 0.7 |
| 2024 | 6.8°C | 5.3°C | 3.8°C | 11.4°C | -0.4°C | 164 mm | 89% | 5.5 m/s | 0.7 |
| 2023 | 7.3°C | 5.8°C | 4.4°C | 11.0°C | 0.6°C | 127 mm | 91% | 5.8 m/s | 0.7 |
| 2022 | 7.2°C | 5.7°C | 4.1°C | 11.4°C | 1.1°C | 50 mm | 90% | 4.8 m/s | 0.7 |
| 2021 | 5.1°C | 3.8°C | 2.5°C | 9.0°C | 0.7°C | 172 mm | 90% | 4.7 m/s | 0.6 |
| 2020 | 7.8°C | 6.5°C | 5.2°C | 10.9°C | 2.9°C | 109 mm | 92% | 5.6 m/s | 0.6 |
| 2019 | 6.0°C | 4.7°C | 3.4°C | 9.4°C | -0.2°C | 62 mm | 89% | 4.7 m/s | 0.7 |
| 2018 | 6.4°C | 5.0°C | 3.7°C | 10.2°C | 0.9°C | 129 mm | 91% | 6.1 m/s | 0.7 |
| 2017 | 6.2°C | 4.7°C | 3.3°C | 9.4°C | -0.6°C | 67 mm | 92% | 4.8 m/s | 0.6 |
| 2016 | 6.9°C | 5.7°C | 4.4°C | 11.2°C | 0.8°C | 175 mm | 90% | 6.1 m/s | 0.6 |
| 2015 | 6.5°C | 5.0°C | 3.5°C | 11.7°C | 0.5°C | 130 mm | 88% | 7 m/s | 0.7 |
| 2014 | 6.9°C | 5.6°C | 4.3°C | 9.4°C | 1.0°C | 149 mm | 91% | 6 m/s | 0.6 |
| 2013 | 5.2°C | 4.0°C | 2.8°C | 9.8°C | -1.4°C | 95 mm | 91% | 5.3 m/s | 0.6 |
| 2012 | 6.8°C | 5.4°C | 3.9°C | 10.8°C | 0.3°C | 91 mm | 90% | 6.2 m/s | 0.7 |
| 2011 | 5.0°C | 3.5°C | 2.1°C | 9.2°C | -0.5°C | 90 mm | 91% | 4.2 m/s | 0.7 |
| 2010 | 3.4°C | 2.2°C | 1.0°C | 6.8°C | -2.1°C | 69 mm | 91% | 4.8 m/s | 0.6 |
| 2009 | 5.3°C | 3.9°C | 2.5°C | 9.2°C | -1.7°C | 123 mm | 90% | 5.4 m/s | 0.7 |
| 2008 🌧️ | 7.8°C | 6.4°C | 5.0°C | 10.6°C | 1.0°C | 206 mm | 91% | 6.6 m/s | 0.5 |
| 2007 🔥 | 8.5°C | 7.0°C | 5.6°C | 11.1°C | 0.9°C | 150 mm | 89% | 7.6 m/s | 0.7 |
| 2006 | 6.3°C | 4.8°C | 3.3°C | 10.1°C | 0.3°C | 58 mm | 92% | 4.6 m/s | 0.7 |
| 2005 | 8.0°C | 6.4°C | 4.8°C | 11.3°C | 0.7°C | 100 mm | 89% | 7.5 m/s | 0.6 |
| 2004 | 7.2°C | 5.9°C | 4.5°C | 10.4°C | 0.4°C | 145 mm | 91% | 5.9 m/s | 0.6 |
| 2003 | 6.2°C | 4.9°C | 3.6°C | 9.6°C | -1.2°C | 100 mm | 90% | 6.2 m/s | 0.7 |
| 2002 | 7.3°C | 5.9°C | 4.4°C | 10.5°C | -1.8°C | 115 mm | 92% | 5.9 m/s | 0.6 |
| 2001 | 5.0°C | 3.8°C | 2.6°C | 7.9°C | -0.8°C | 57 mm | 91% | 4.9 m/s | 0.8 |
| 2000 | 7.0°C | 5.6°C | 4.2°C | 9.8°C | 1.4°C | 104 mm | 91% | 5.6 m/s | 0.7 |
| 1999 | 7.1°C | 5.6°C | 4.2°C | 10.5°C | 0.6°C | 155 mm | 91% | 6 m/s | 0.7 |
| 1998 | 6.7°C | 5.4°C | 4.0°C | 11.1°C | 1.0°C | 145 mm | 89% | 5.5 m/s | 0.6 |
| 1997 | 4.0°C | 2.6°C | 1.1°C | 8.1°C | -2.4°C | 16 mm | 93% | 3.7 m/s | 0.7 |
| 1996 | 5.0°C | 3.9°C | 2.9°C | 9.1°C | -1.1°C | 69 mm | 92% | 6.8 m/s | 0.6 |
| 1995 | 6.3°C | 4.6°C | 2.9°C | 10.0°C | -0.1°C | 163 mm | 89% | 6.9 m/s | 0.6 |
| 1994 | 6.3°C | 4.8°C | 3.4°C | 9.7°C | 0.1°C | 134 mm | 91% | 6.6 m/s | 0.6 |
| 1993 | 6.8°C | 5.0°C | 3.2°C | 10.3°C | -2.2°C | 129 mm | 89% | 7.5 m/s | 0.6 |
| 1992 | 5.8°C | 4.3°C | 2.8°C | 9.5°C | -1.2°C | 46 mm | 92% | 4.4 m/s | 0.8 |
| 1991 | 4.7°C | 3.2°C | 1.8°C | 10.0°C | -0.6°C | 103 mm | 88% | 5.6 m/s | 0.7 |
| 1990 | 7.8°C | 6.4°C | 5.1°C | 10.5°C | 2.5°C | 156 mm | 90% | 7.2 m/s | 0.6 |
| 1989 | 7.8°C | 6.4°C | 5.0°C | 10.6°C | 2.1°C | 66 mm | 91% | 6 m/s | 0.7 |
| 1988 | 6.4°C | 5.1°C | 3.8°C | 10.5°C | 1.3°C | 153 mm | 91% | 5.9 m/s | 0.7 |
| 1987 ❄️ | 2.7°C | 1.3°C | -0.1°C | 8.4°C | -5.2°C | 40 mm | 90% | 4.3 m/s | 0.6 |
| 1986 | 4.7°C | 3.3°C | 2.0°C | 9.0°C | -0.6°C | 136 mm | 89% | 7 m/s | 0.6 |
| 1985 | 3.1°C | 1.6°C | 0.1°C | 8.2°C | -4.8°C | 70 mm | 90% | 4.6 m/s | 0.8 |
| 1984 | 4.8°C | 3.4°C | 1.9°C | 9.7°C | -1.5°C | 161 mm | 87% | 6.9 m/s | 0.5 |
| 1983 | 7.3°C | 5.8°C | 4.2°C | 10.3°C | -0.1°C | 143 mm | 90% | 7.9 m/s | — |
| 1982 | 4.2°C | 2.9°C | 1.6°C | 8.6°C | -5.5°C | 100 mm | 93% | 5.4 m/s | — |
| 1981 | 6.6°C | 5.0°C | 3.4°C | 9.3°C | 0.1°C | 104 mm | 90% | 6 m/s | — |
Actual recorded January data for each year, 1981–2025 — sourced from NASA POWER.
The average high in January is around 6.1°C with lows near 3.3°C (mean 4.7°C), based on 45 years of NASA POWER data.
January averages 112 mm of rainfall in Thornton, a relatively wet time of year. The wettest on record was 206 mm in 2008.
The hottest January reached 11.7°C in 2015. The coldest dipped to -5.5°C in 1982.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average January temperatures have risen by about 1.3°C. Daytime highs moved from 5.2°C to 6.4°C and overnight lows from 2.2°C to 3.5°C over the same span.
January is one of the cooler months of the year in Thornton and a relatively wet time of year, so plan for around 6.1°C daytime highs and 3.3°C at night.
Not quite — January is the 2nd coolest month in Thornton, averaging 4.7°C.
For January in Thornton, pack warm layers and a jacket for chilly mornings, with typical highs of 6.1°C and lows of 3.3°C. Bring an umbrella or light rain jacket too.
Relative humidity in January averages 90% — quite humid.
Average wind speed in January is 5.8 m/s. The windiest January on record averaged 7.9 m/s (1983).
The wettest January on record was 2008 with 206 mm. On average, January sees 112 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 Thornton behaves each January, 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 January specifically, along with year-by-year records and how the month has changed over the decades.
