March is one of the cooler months of the year in Longmont, with average highs near 11.8°C and lows around -2.5°C (mean 4.7°C). It is about average for rainfall, averaging 41 mm of rainfall and 52% relative humidity across the period.
March is one of the cooler months of the year in Longmont. Across 45 years of records, the warmest March in Longmont was 2012 — when the month averaged 8.9°C — while the coldest was 2023 at 1.8°C. Typical March days reach 11.8°C with nights near -2.5°C. The long-term trend is warming, about 0.3°C per decade.
March is about average for rainfall in Longmont, averaging 41 mm of rainfall. The wettest March on record was 1983 with 102 mm, while the driest was 2012 at 3 mm.
Relative humidity in Longmont during March averages 52%. The most humid March was 1983 at 65%, and the least humid was 2012 at 38%.
March receives about 4.7 kWh/m²/day of solar energy in Longmont. The sunniest March was 2012 at 5.4 kWh/m²/day, and the cloudiest was 2003 at 3.8.
Average wind speed in Longmont during March is 2.7 m/s. The windiest March was 1988 at 3.7 m/s, while the calmest were 2001 and 2019 at 2.2 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 3.9°C | 4.7°C | 4.7°C | 5.4°C | 4.4°C | +0.5°C |
| Avg High | 10.7°C | 11.9°C | 11.8°C | 12.8°C | 11.6°C | +0.9°C |
| Avg Low | -2.9°C | -2.5°C | -2.3°C | -2.0°C | -2.9°C | 0°C |
| Avg Rain | 42 mm | 46 mm | 38 mm | 35 mm | 47 mm | +4 mm |
March temperatures in Longmont have risen by about 0.8°C between 1981–1985 and 2021–2025.
March has ranged from a record low of -17.7°C (2002) to a record high of 27.1°C (2012).
Rainfall in March is about average for rainfall, averaging 41 mm, with a wettest year of 102 mm.
Daytime highs and overnight lows have shifted differently — highs rose about 0.4°C per decade while lows rose 0.1°C per decade, widening the gap between day and night.
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, March — with days averaging 11.8°C and nights around -2.5°C (mean 4.7°C) and moderate rainfall (41 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 | 14.9°C | 7.0°C | -0.8°C | 23.2°C | -5.9°C | 42 mm | 46% | 2.9 m/s | 4.5 |
| 2024 | 11.6°C | 4.5°C | -2.6°C | 17.7°C | -7.1°C | 59 mm | 57% | 2.3 m/s | 4.9 |
| 2023 ❄️ | 8.6°C | 1.8°C | -5.0°C | 18.5°C | -10.7°C | 25 mm | 53% | 2.4 m/s | 4.8 |
| 2022 | 11.3°C | 3.9°C | -3.4°C | 24.2°C | -14.7°C | 36 mm | 49% | 3 m/s | 4.9 |
| 2021 | 10.2°C | 3.4°C | -3.4°C | 21.0°C | -11.6°C | 73 mm | 57% | 2.5 m/s | 4.8 |
| 2020 | 12.9°C | 5.5°C | -2.0°C | 18.1°C | -9.5°C | 45 mm | 56% | 2.5 m/s | 4.7 |
| 2019 | 9.4°C | 2.4°C | -4.7°C | 21.1°C | -15.1°C | 67 mm | 61% | 2.2 m/s | 4.8 |
| 2018 | 12.9°C | 5.2°C | -2.5°C | 22.0°C | -6.5°C | 35 mm | 49% | 2.7 m/s | 4.6 |
| 2017 | 15.8°C | 8.2°C | 0.7°C | 25.0°C | -7.0°C | 28 mm | 49% | 3.2 m/s | 4.6 |
| 2016 | 11.7°C | 4.7°C | -2.2°C | 21.3°C | -11.0°C | 56 mm | 52% | 2.6 m/s | 4.3 |
| 2015 | 14.8°C | 7.2°C | -0.3°C | 25.7°C | -12.5°C | 20 mm | 51% | 2.4 m/s | 5 |
| 2014 | 11.2°C | 4.0°C | -3.2°C | 18.9°C | -8.1°C | 31 mm | 54% | 3.1 m/s | 4.8 |
| 2013 | 11.2°C | 3.7°C | -3.7°C | 21.9°C | -14.5°C | 36 mm | 52% | 2.6 m/s | 4.5 |
| 2012 🔥 | 17.0°C | 8.9°C | 0.9°C | 27.1°C | -7.7°C | 3 mm | 38% | 2.8 m/s | 5.4 |
| 2011 | 13.0°C | 5.6°C | -1.8°C | 21.9°C | -6.1°C | 22 mm | 50% | 2.8 m/s | 4.8 |
| 2010 | 10.9°C | 4.0°C | -2.9°C | 23.8°C | -12.1°C | 55 mm | 56% | 2.8 m/s | 4.9 |
| 2009 | 12.8°C | 5.5°C | -1.9°C | 23.2°C | -11.8°C | 30 mm | 44% | 2.9 m/s | 4.9 |
| 2008 | 10.8°C | 3.5°C | -3.8°C | 19.5°C | -7.5°C | 26 mm | 50% | 3.1 m/s | 4.6 |
| 2007 | 14.3°C | 7.2°C | 0.0°C | 22.6°C | -12.1°C | 36 mm | 52% | 2.8 m/s | 4.5 |
| 2006 | 10.6°C | 3.7°C | -3.3°C | 19.8°C | -9.9°C | 35 mm | 53% | 2.4 m/s | 4.5 |
| 2005 | 10.2°C | 3.7°C | -2.9°C | 21.2°C | -9.2°C | 27 mm | 53% | 2.9 m/s | 4.5 |
| 2004 | 16.4°C | 8.3°C | 0.2°C | 25.8°C | -5.3°C | 15 mm | 43% | 2.6 m/s | 5.1 |
| 2003 | 10.7°C | 4.3°C | -2.1°C | 22.8°C | -9.9°C | 99 mm | 56% | 3.2 m/s | 3.8 |
| 2002 | 9.7°C | 2.3°C | -5.2°C | 21.5°C | -17.7°C | 25 mm | 49% | 2.7 m/s | 5 |
| 2001 | 10.8°C | 4.2°C | -2.3°C | 19.6°C | -6.1°C | 36 mm | 57% | 2.2 m/s | 4.1 |
| 2000 | 11.4°C | 4.7°C | -2.1°C | 20.6°C | -7.8°C | 53 mm | 55% | 2.7 m/s | 4.3 |
| 1999 | 14.5°C | 6.5°C | -1.6°C | 23.3°C | -6.3°C | 19 mm | 47% | 2.3 m/s | 5.1 |
| 1998 | 9.8°C | 3.0°C | -3.8°C | 22.2°C | -13.0°C | 49 mm | 59% | 2.3 m/s | 4.8 |
| 1997 | 14.1°C | 5.9°C | -2.4°C | 24.2°C | -9.9°C | 19 mm | 46% | 2.8 m/s | 5.1 |
| 1996 | 10.0°C | 2.9°C | -4.1°C | 20.0°C | -14.2°C | 41 mm | 53% | 2.6 m/s | 4.7 |
| 1995 | 11.8°C | 4.8°C | -2.2°C | 22.1°C | -9.7°C | 32 mm | 51% | 2.6 m/s | 4.5 |
| 1994 | 13.2°C | 5.7°C | -1.9°C | 22.6°C | -8.2°C | 30 mm | 50% | 2.6 m/s | 4.7 |
| 1993 | 11.8°C | 4.8°C | -2.1°C | 21.6°C | -12.0°C | 42 mm | 55% | 3 m/s | 4.3 |
| 1992 | 11.6°C | 4.9°C | -1.7°C | 18.2°C | -9.9°C | 96 mm | 61% | 2.3 m/s | 4.3 |
| 1991 | 11.3°C | 4.2°C | -2.8°C | 18.2°C | -6.1°C | 32 mm | 48% | 3.3 m/s | 4.7 |
| 1990 | 10.9°C | 4.0°C | -2.8°C | 20.0°C | -7.9°C | 99 mm | 61% | 2.5 m/s | 4.4 |
| 1989 | 14.3°C | 6.2°C | -2.0°C | 24.7°C | -16.0°C | 23 mm | 49% | 2.3 m/s | 4.5 |
| 1988 | 8.4°C | 2.0°C | -4.4°C | 22.0°C | -10.7°C | 47 mm | 54% | 3.7 m/s | 4.5 |
| 1987 | 9.5°C | 2.9°C | -3.7°C | 21.4°C | -12.9°C | 37 mm | 55% | 2.9 m/s | 4.6 |
| 1986 | 14.6°C | 7.2°C | -0.1°C | 24.6°C | -6.5°C | 20 mm | 50% | 2.6 m/s | 4.7 |
| 1985 | 11.3°C | 4.2°C | -2.8°C | 20.7°C | -9.3°C | 22 mm | 49% | 2.8 m/s | 4.8 |
| 1984 | 8.4°C | 2.2°C | -4.0°C | 16.6°C | -9.7°C | 47 mm | 60% | 2.7 m/s | 4.3 |
| 1983 🌧️ | 8.5°C | 2.5°C | -3.4°C | 19.9°C | -11.3°C | 102 mm | 65% | 2.6 m/s | — |
| 1982 | 11.3°C | 4.2°C | -2.9°C | 19.7°C | -8.2°C | 22 mm | 49% | 3 m/s | — |
| 1981 | 9.8°C | 3.5°C | -2.9°C | 20.7°C | -7.6°C | 62 mm | 56% | 2.7 m/s | — |
Actual recorded March data for each year, 1981–2025 — sourced from NASA POWER.
The average high in March is around 11.8°C with lows near -2.5°C (mean 4.7°C), based on 45 years of NASA POWER data.
March averages 41 mm of rainfall in Longmont, about average for rainfall. The wettest on record was 102 mm in 1983.
The hottest March reached 27.1°C in 2012. The coldest dipped to -17.7°C in 2002.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average March temperatures have risen by about 0.8°C. Daytime highs moved from 9.9°C to 11.3°C and overnight lows from -3.2°C to -3°C over the same span.
March is one of the cooler months of the year in Longmont and about average for rainfall, so plan for around 11.8°C daytime highs and -2.5°C at night.
Not quite — March is the 5th coolest month in Longmont, averaging 4.7°C.
For March in Longmont, pack warm layers and a jacket for chilly mornings, with typical highs of 11.8°C and lows of -2.5°C.
Relative humidity in March averages 52% — relatively dry.
Average wind speed in March is 2.7 m/s. The windiest March on record averaged 3.7 m/s (1988).
The wettest March on record was 1983 with 102 mm. On average, March sees 41 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 March, 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 March specifically, along with year-by-year records and how the month has changed over the decades.
