January is one of the cooler months of the year in Longmont, with average highs near 5.6°C and lows around -5.6°C (mean 0°C). It is one of the drier months, averaging 21 mm of rainfall and 56% relative humidity across the period.
January is one of the cooler months of the year in Longmont. Across 45 years of records, the warmest January in Longmont was 2003 — when the month averaged 3.6°C — while the coldest was 1988 at -4.6°C. Typical January days reach 5.6°C with nights near -5.6°C. The long-term January temperature trend is broadly flat.
January is one of the drier months in Longmont, averaging 21 mm of rainfall. The wettest January on record was 1996 with 45 mm, while the driest was 1983 at 6 mm.
Relative humidity in Longmont during January averages 56%. The most humid Januarys were 1988 and 2023 at 67%, and the least humid was 1981 at 46%.
January receives about 2.5 kWh/m²/day of solar energy in Longmont. The sunniest January was 2016 at 2.8 kWh/m²/day, and the cloudiest was 1996 at 2.1.
Average wind speed in Longmont during January is 2.9 m/s. The windiest January was 2009 at 4 m/s, while the calmest was 1981 at 2.1 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | -0.4°C | -0.1°C | 0.6°C | 0.4°C | -0.7°C | -0.3°C |
| Avg High | 5.2°C | 5.4°C | 6.2°C | 6.1°C | 4.8°C | -0.4°C |
| Avg Low | -6.1°C | -5.6°C | -5.0°C | -5.3°C | -6.3°C | -0.2°C |
| Avg Rain | 17 mm | 26 mm | 20 mm | 21 mm | 21 mm | +4 mm |
January temperatures in Longmont have fallen by about 0.7°C between 1981–1985 and 2021–2025.
January has ranged from a record low of -24.1°C (2024) to a record high of 20.2°C (2015).
Rainfall in January is one of the drier months, averaging 21 mm, with a wettest year of 45 mm.
A quieter season to visit Longmont
If your dates are flexible, the more temperate months of August and July tend to be the most comfortable for visiting Longmont. That said, January — with days averaging 5.6°C and nights around -5.6°C (mean 0°C) and low rainfall (21 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 | 2.7°C | -3.0°C | -8.8°C | 13.2°C | -18.4°C | 28 mm | 58% | 2.9 m/s | 2.5 |
| 2024 | 4.6°C | -1.0°C | -6.6°C | 16.2°C | -24.1°C | 21 mm | 60% | 2.4 m/s | 2.3 |
| 2023 | 2.8°C | -2.2°C | -7.1°C | 13.0°C | -18.7°C | 28 mm | 67% | 2.3 m/s | 2.5 |
| 2022 | 6.0°C | -0.1°C | -6.2°C | 15.2°C | -16.9°C | 29 mm | 57% | 3 m/s | 2.6 |
| 2021 | 6.2°C | 0.8°C | -4.7°C | 14.2°C | -9.2°C | 11 mm | 54% | 2.7 m/s | 2.5 |
| 2020 | 6.4°C | 1.1°C | -4.2°C | 11.5°C | -11.1°C | 11 mm | 53% | 2.8 m/s | 2.4 |
| 2019 | 5.9°C | 0.5°C | -5.0°C | 13.9°C | -15.4°C | 30 mm | 58% | 2.6 m/s | 2.6 |
| 2018 | 7.7°C | 1.7°C | -4.4°C | 15.7°C | -12.3°C | 18 mm | 53% | 2.6 m/s | 2.5 |
| 2017 | 3.9°C | -1.5°C | -6.9°C | 12.8°C | -23.1°C | 42 mm | 62% | 2.7 m/s | 2.3 |
| 2016 | 5.9°C | 0.4°C | -5.1°C | 14.6°C | -13.4°C | 17 mm | 58% | 2.6 m/s | 2.8 |
| 2015 | 6.6°C | 0.9°C | -4.9°C | 20.2°C | -16.0°C | 13 mm | 64% | 2.8 m/s | 2.4 |
| 2014 | 5.1°C | -0.4°C | -5.9°C | 12.8°C | -17.2°C | 34 mm | 57% | 3.7 m/s | 2.5 |
| 2013 | 6.3°C | 0.3°C | -5.6°C | 15.6°C | -17.0°C | 11 mm | 47% | 2.7 m/s | 2.7 |
| 2012 | 8.2°C | 2.2°C | -3.7°C | 17.4°C | -9.8°C | 12 mm | 48% | 3.1 m/s | 2.5 |
| 2011 | 5.0°C | -0.6°C | -6.3°C | 15.5°C | -17.0°C | 22 mm | 57% | 3.4 m/s | 2.4 |
| 2010 | 6.1°C | 0.4°C | -5.3°C | 13.6°C | -17.7°C | 10 mm | 55% | 2.2 m/s | 2.6 |
| 2009 | 6.8°C | 1.2°C | -4.4°C | 16.9°C | -14.5°C | 21 mm | 52% | 4 m/s | 2.5 |
| 2008 | 3.3°C | -2.4°C | -8.0°C | 12.3°C | -17.2°C | 17 mm | 55% | 3.3 m/s | 2.6 |
| 2007 | 2.4°C | -3.2°C | -8.7°C | 11.9°C | -18.0°C | 22 mm | 63% | 3 m/s | 2.7 |
| 2006 | 8.2°C | 2.3°C | -3.6°C | 17.1°C | -9.1°C | 16 mm | 49% | 3.7 m/s | 2.6 |
| 2005 | 7.9°C | 2.0°C | -3.9°C | 19.7°C | -14.8°C | 34 mm | 64% | 2.3 m/s | 2.6 |
| 2004 | 6.6°C | 1.2°C | -4.3°C | 14.1°C | -15.0°C | 19 mm | 51% | 2.6 m/s | 2.5 |
| 2003 🔥 | 9.6°C | 3.6°C | -2.3°C | 18.9°C | -6.1°C | 7 mm | 55% | 2.8 m/s | 2.3 |
| 2002 | 5.5°C | -0.2°C | -6.0°C | 14.6°C | -12.4°C | 19 mm | 52% | 2.9 m/s | 2.5 |
| 2001 | 5.6°C | 0.3°C | -5.0°C | 16.1°C | -11.4°C | 17 mm | 53% | 2.7 m/s | 2.5 |
| 2000 | 6.3°C | 1.1°C | -4.2°C | 14.1°C | -10.7°C | 30 mm | 55% | 2.6 m/s | 2.5 |
| 1999 | 6.2°C | 1.1°C | -3.9°C | 12.3°C | -12.6°C | 33 mm | 59% | 2.7 m/s | 2.5 |
| 1998 | 6.2°C | 1.0°C | -4.2°C | 13.9°C | -10.4°C | 24 mm | 60% | 2.5 m/s | 2.6 |
| 1997 | 3.9°C | -1.5°C | -7.0°C | 18.8°C | -21.7°C | 34 mm | 63% | 2.9 m/s | 2.4 |
| 1996 🌧️ | 3.7°C | -2.2°C | -8.1°C | 15.2°C | -16.9°C | 45 mm | 60% | 3.5 m/s | 2.1 |
| 1995 | 6.3°C | 0.8°C | -4.7°C | 13.9°C | -12.5°C | 18 mm | 56% | 2.3 m/s | 2.6 |
| 1994 | 5.8°C | 0.6°C | -4.7°C | 14.6°C | -16.3°C | 21 mm | 55% | 2.9 m/s | 2.6 |
| 1993 | 4.7°C | -0.9°C | -6.5°C | 13.8°C | -15.6°C | 18 mm | 62% | 2.4 m/s | 2.6 |
| 1992 | 6.6°C | 0.8°C | -5.0°C | 17.2°C | -17.5°C | 20 mm | 51% | 3.3 m/s | 2.7 |
| 1991 | 4.0°C | -1.7°C | -7.4°C | 10.3°C | -16.6°C | 19 mm | 57% | 2.8 m/s | 2.5 |
| 1990 | 6.7°C | 1.0°C | -4.6°C | 16.9°C | -11.0°C | 23 mm | 53% | 3.8 m/s | 2.6 |
| 1989 | 5.5°C | -0.2°C | -5.9°C | 12.5°C | -14.2°C | 28 mm | 54% | 3.5 m/s | 2.6 |
| 1988 ❄️ | 1.2°C | -4.6°C | -10.4°C | 10.9°C | -18.4°C | 27 mm | 67% | 3.4 m/s | 2.3 |
| 1987 | 5.3°C | -0.3°C | -5.9°C | 14.9°C | -15.2°C | 23 mm | 57% | 3 m/s | 2.6 |
| 1986 | 9.6°C | 3.4°C | -2.9°C | 15.6°C | -10.5°C | 9 mm | 52% | 3.4 m/s | 2.7 |
| 1985 | 2.5°C | -2.8°C | -8.0°C | 9.9°C | -19.8°C | 15 mm | 61% | 2.7 m/s | 2.5 |
| 1984 | 4.4°C | -1.3°C | -7.1°C | 14.5°C | -22.1°C | 9 mm | 59% | 3.4 m/s | 2.5 |
| 1983 | 6.6°C | 1.5°C | -3.5°C | 13.0°C | -9.3°C | 6 mm | 57% | 2.7 m/s | — |
| 1982 | 3.6°C | -2.0°C | -7.7°C | 14.4°C | -18.4°C | 25 mm | 57% | 3.6 m/s | — |
| 1981 | 8.5°C | 2.7°C | -3.2°C | 15.9°C | -8.0°C | 9 mm | 46% | 2.1 m/s | — |
Actual recorded January data for each year, 1981–2025 — sourced from NASA POWER.
The average high in January is around 5.6°C with lows near -5.6°C (mean 0°C), based on 45 years of NASA POWER data.
January averages 21 mm of rainfall in Longmont, one of the drier months. The wettest on record was 45 mm in 1996.
The hottest January reached 20.2°C in 2015. The coldest dipped to -24.1°C in 2024.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average January temperatures have fallen by about 0.7°C. Daytime highs moved from 5.1°C to 4.5°C and overnight lows from -5.9°C to -6.7°C over the same span.
January is one of the cooler months of the year in Longmont and one of the drier months, so plan for around 5.6°C daytime highs and -5.6°C at night.
Yes — January is the coldest month of the year in Longmont, averaging 0°C.
For January in Longmont, pack warm layers and a jacket for chilly mornings, with typical highs of 5.6°C and lows of -5.6°C.
Relative humidity in January averages 56% — moderately humid.
Average wind speed in January is 2.9 m/s. The windiest January on record averaged 4 m/s (2009).
The wettest January on record was 1996 with 45 mm. On average, January sees 21 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 Longmont 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.
