March is one of the cooler months of the year in Helena, with average highs near 5°C and lows around -6.1°C (mean -0.5°C). It is about average for rainfall, averaging 39 mm of rainfall and 75% relative humidity across the period.
March is one of the cooler months of the year in Helena. Across 45 years of records, the warmest March in Helena was 1992 — when the month averaged 3.5°C — while the coldest was 2019 at -5.3°C. Typical March days reach 5°C with nights near -6.1°C. The long-term March temperature trend is broadly flat.
March is about average for rainfall in Helena, averaging 39 mm of rainfall. The wettest March on record was 2014 with 74 mm, while the driest was 2021 at 17 mm.
Relative humidity in Helena during March averages 75%. The most humid March was 2019 at 87%, and the least humid was 1994 at 66%.
March receives about 3.8 kWh/m²/day of solar energy in Helena. The sunniest March was 1992 at 4.4 kWh/m²/day, and the cloudiest was 1989 at 3.2.
Average wind speed in Helena during March is 1.6 m/s. The windiest March was 1988 at 2 m/s, while the calmest was 1992 at 1.1 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | -0.5°C | -0.4°C | -0.8°C | -0.5°C | -0.4°C | +0.1°C |
| Avg High | 4.7°C | 5.3°C | 4.8°C | 5.0°C | 4.9°C | +0.2°C |
| Avg Low | -5.8°C | -6.2°C | -6.5°C | -6.1°C | -5.7°C | +0.1°C |
| Avg Rain | 42 mm | 34 mm | 39 mm | 44 mm | 32 mm | -11 mm |
March temperatures in Helena have risen by about 0.4°C between 1981–1985 and 2021–2025.
March has ranged from a record low of -31.4°C (2019) to a record high of 20.1°C (2004).
Rainfall in March is about average for rainfall, averaging 39 mm, with a wettest year of 74 mm.
A good time to visit Helena
March is a good time to visit Helena, with days averaging 5°C and nights around -6.1°C (mean -0.5°C, cooler than Helena's yearly average) and moderate rainfall. July and August are marginally more temperate, but March still suits most travellers.
| Year | Avg High | Avg Temp | Avg Low | Hottest Day | Coldest Day | Rainfall | Humidity | Wind | Solar |
|---|---|---|---|---|---|---|---|---|---|
| 2025 | 7.2°C | 2.0°C | -3.1°C | 19.1°C | -8.0°C | 39 mm | 70% | 1.6 m/s | 3.7 |
| 2024 | 5.2°C | -0.1°C | -5.4°C | 15.6°C | -14.5°C | 31 mm | 74% | 1.3 m/s | 3.7 |
| 2023 | 0.9°C | -4.3°C | -9.4°C | 7.8°C | -15.1°C | 51 mm | 79% | 1.4 m/s | 4 |
| 2022 | 6.0°C | 0.4°C | -5.3°C | 18.6°C | -20.0°C | 21 mm | 71% | 1.7 m/s | 3.8 |
| 2021 | 5.9°C | 0.3°C | -5.2°C | 14.3°C | -14.0°C | 17 mm | 71% | 1.5 m/s | 4.1 |
| 2020 | 4.2°C | -0.9°C | -6.1°C | 13.3°C | -13.0°C | 32 mm | 74% | 1.7 m/s | 3.9 |
| 2019 ❄️ | 1.1°C | -5.3°C | -11.6°C | 12.8°C | -31.4°C | 29 mm | 87% | 1.2 m/s | 4.1 |
| 2018 | 2.7°C | -2.8°C | -8.3°C | 11.2°C | -17.1°C | 45 mm | 83% | 1.5 m/s | 3.7 |
| 2017 | 7.3°C | 1.7°C | -3.8°C | 18.2°C | -11.6°C | 52 mm | 78% | 1.7 m/s | 3.5 |
| 2016 | 5.9°C | 0.9°C | -4.1°C | 14.3°C | -10.8°C | 44 mm | 75% | 1.7 m/s | 3.5 |
| 2015 | 8.5°C | 2.2°C | -4.0°C | 17.6°C | -17.8°C | 21 mm | 75% | 1.7 m/s | 3.7 |
| 2014 🌧️ | 2.2°C | -2.3°C | -6.8°C | 11.4°C | -28.3°C | 74 mm | 83% | 1.7 m/s | 3.6 |
| 2013 | 4.6°C | -0.8°C | -6.1°C | 12.0°C | -14.8°C | 25 mm | 72% | 1.6 m/s | 3.9 |
| 2012 | 7.9°C | 1.4°C | -5.1°C | 17.2°C | -13.5°C | 62 mm | 78% | 1.9 m/s | 3.4 |
| 2011 | 3.9°C | -1.2°C | -6.2°C | 10.2°C | -14.1°C | 49 mm | 81% | 1.6 m/s | 3.5 |
| 2010 | 6.3°C | 0.8°C | -4.8°C | 13.4°C | -9.9°C | 34 mm | 75% | 1.4 m/s | 4.1 |
| 2009 | 2.6°C | -3.1°C | -8.8°C | 12.8°C | -19.3°C | 74 mm | 79% | 1.6 m/s | 3.7 |
| 2008 | 1.6°C | -3.2°C | -8.1°C | 9.2°C | -13.5°C | 32 mm | 76% | 1.7 m/s | 3.8 |
| 2007 | 8.2°C | 1.9°C | -4.5°C | 16.5°C | -15.9°C | 29 mm | 74% | 1.7 m/s | 3.8 |
| 2006 | 4.0°C | -1.4°C | -6.9°C | 12.4°C | -14.8°C | 32 mm | 74% | 1.5 m/s | 3.7 |
| 2005 | 5.2°C | 0.0°C | -5.2°C | 14.2°C | -12.1°C | 47 mm | 74% | 1.7 m/s | 3.4 |
| 2004 | 8.5°C | 2.2°C | -4.1°C | 20.1°C | -11.7°C | 26 mm | 70% | 1.9 m/s | 3.8 |
| 2003 | 4.3°C | -1.2°C | -6.7°C | 15.2°C | -21.2°C | 52 mm | 79% | 1.7 m/s | 3.3 |
| 2002 | 0.8°C | -5.1°C | -11.0°C | 11.9°C | -21.9°C | 37 mm | 78% | 1.7 m/s | 3.8 |
| 2001 | 6.9°C | 1.0°C | -4.9°C | 12.9°C | -11.0°C | 28 mm | 67% | 1.5 m/s | 3.7 |
| 2000 | 5.8°C | 0.4°C | -5.1°C | 15.7°C | -9.9°C | 29 mm | 72% | 1.7 m/s | 3.9 |
| 1999 | 6.5°C | 0.2°C | -6.1°C | 17.6°C | -14.5°C | 22 mm | 70% | 1.5 m/s | 3.9 |
| 1998 | 4.4°C | -1.2°C | -6.8°C | 12.2°C | -18.4°C | 39 mm | 78% | 1.2 m/s | 3.7 |
| 1997 | 3.3°C | -2.1°C | -7.6°C | 14.7°C | -17.2°C | 44 mm | 81% | 1.7 m/s | 3.8 |
| 1996 | 2.0°C | -3.5°C | -9.1°C | 11.9°C | -19.2°C | 47 mm | 82% | 1.6 m/s | 3.7 |
| 1995 | 3.9°C | -1.6°C | -7.0°C | 12.7°C | -16.6°C | 44 mm | 75% | 1.6 m/s | 3.6 |
| 1994 | 7.0°C | 1.1°C | -4.8°C | 17.8°C | -10.5°C | 20 mm | 66% | 1.6 m/s | 4 |
| 1993 | 6.9°C | 0.8°C | -5.2°C | 17.3°C | -13.3°C | 21 mm | 74% | 1.5 m/s | 3.9 |
| 1992 🔥 | 9.8°C | 3.5°C | -2.9°C | 15.3°C | -5.9°C | 23 mm | 67% | 1.1 m/s | 4.4 |
| 1991 | 4.0°C | -1.0°C | -6.1°C | 14.9°C | -13.2°C | 47 mm | 73% | 1.7 m/s | 3.8 |
| 1990 | 5.3°C | -0.5°C | -6.4°C | 14.5°C | -15.4°C | 37 mm | 72% | 1.5 m/s | 3.9 |
| 1989 | 3.0°C | -2.4°C | -7.7°C | 14.4°C | -26.6°C | 52 mm | 80% | 1.5 m/s | 3.2 |
| 1988 | 3.9°C | -1.1°C | -6.1°C | 14.2°C | -14.4°C | 37 mm | 69% | 2 m/s | 3.7 |
| 1987 | 4.9°C | -0.5°C | -5.9°C | 14.9°C | -19.0°C | 38 mm | 75% | 1.5 m/s | 3.7 |
| 1986 | 8.8°C | 2.9°C | -3.0°C | 17.9°C | -6.4°C | 30 mm | 72% | 1.6 m/s | 3.7 |
| 1985 | 3.0°C | -2.6°C | -8.2°C | 12.6°C | -17.6°C | 35 mm | 75% | 1.6 m/s | 4.3 |
| 1984 | 4.2°C | -0.4°C | -5.0°C | 10.8°C | -11.0°C | 46 mm | 80% | 1.4 m/s | 3.8 |
| 1983 | 5.4°C | 0.4°C | -4.7°C | 14.6°C | -12.2°C | 37 mm | 76% | 1.4 m/s | — |
| 1982 | 2.6°C | -2.3°C | -7.3°C | 8.6°C | -13.1°C | 60 mm | 81% | 1.7 m/s | — |
| 1981 | 6.8°C | 1.2°C | -4.4°C | 12.2°C | -8.8°C | 47 mm | 69% | 1.4 m/s | — |
Actual recorded March data for each year, 1981–2025 — sourced from NASA POWER.
The average high in March is around 5°C with lows near -6.1°C (mean -0.5°C), based on 45 years of NASA POWER data.
March averages 39 mm of rainfall in Helena, about average for rainfall. The wettest on record was 74 mm in 2014.
The hottest March reached 20.1°C in 2004. The coldest dipped to -31.4°C in 2019.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average March temperatures have risen by about 0.4°C. Daytime highs moved from 4.4°C to 5°C and overnight lows from -5.9°C to -5.7°C over the same span.
March is one of the cooler months of the year in Helena and about average for rainfall, so plan for around 5°C daytime highs and -6.1°C at night.
Not quite — March is the 5th coolest month in Helena, averaging -0.5°C.
For March in Helena, pack warm layers and a jacket for chilly mornings, with typical highs of 5°C and lows of -6.1°C.
Relative humidity in March averages 75% — quite humid.
Average wind speed in March is 1.6 m/s. The windiest March on record averaged 2 m/s (1988).
The wettest March on record was 2014 with 74 mm. On average, March sees 39 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 Helena 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.
