October is close to Helena's year-round average, with average highs near 11.2°C and lows around -1.4°C (mean 4.9°C). It is about average for rainfall, averaging 36 mm of rainfall and 68% relative humidity across the period.
October is close to Helena's year-round average. Across 45 years of records, the warmest Octobers in Helena were 1988 and 2024 — when the month averaged 8.5°C — while the coldest was 2019 at 0.3°C. Typical October days reach 11.2°C with nights near -1.4°C. The long-term trend is warming, about 0.2°C per decade.
October is about average for rainfall in Helena, averaging 36 mm of rainfall. The wettest October on record was 2020 with 68 mm, while the driest was 1987 at 3 mm.
Relative humidity in Helena during October averages 68%. The most humid October was 2009 at 78%, and the least humid was 1987 at 49%.
October receives about 2.8 kWh/m²/day of solar energy in Helena. The sunniest October was 1987 at 3.5 kWh/m²/day, and the cloudiest were 2009 and 2016 at 2.3.
Average wind speed in Helena during October is 1.3 m/s. The windiest Octobers were 1985 and 1990 at 1.6 m/s, while the calmest were 2000, 2005 and 2023, among others at 1.1 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 4.9°C | 4.5°C | 4.5°C | 5.0°C | 6.1°C | +1.2°C |
| Avg High | 11.5°C | 10.8°C | 10.6°C | 11.0°C | 12.5°C | +1°C |
| Avg Low | -1.7°C | -1.8°C | -1.7°C | -1.1°C | -0.4°C | +1.3°C |
| Avg Rain | 26 mm | 35 mm | 40 mm | 40 mm | 41 mm | +14 mm |
October temperatures in Helena have risen by about 3°C between 1981–1985 and 2021–2025.
October has ranged from a record low of -20.1°C (2020) to a record high of 27°C (1992).
Rainfall in October is about average for rainfall, averaging 36 mm, with a wettest year of 68 mm.
A good time to visit Helena
October is a good time to visit Helena, with days averaging 11.2°C and nights around -1.4°C (mean 4.9°C, close to Helena's yearly average) and moderate rainfall. July and August are marginally more temperate, but October still suits most travellers.
| Year | Avg High | Avg Temp | Avg Low | Hottest Day | Coldest Day | Rainfall | Humidity | Wind | Solar |
|---|---|---|---|---|---|---|---|---|---|
| 2025 | 11.6°C | 5.5°C | -0.7°C | 21.7°C | -5.5°C | 43 mm | 69% | 1.2 m/s | 2.7 |
| 2024 | 15.7°C | 8.5°C | 1.2°C | 25.5°C | -5.0°C | 11 mm | 60% | 1.2 m/s | 3.3 |
| 2023 | 11.3°C | 5.1°C | -1.1°C | 23.1°C | -16.3°C | 41 mm | 74% | 1.1 m/s | 2.8 |
| 2022 | 13.8°C | 7.5°C | 1.2°C | 22.4°C | -7.0°C | 47 mm | 67% | 1.2 m/s | 3 |
| 2021 | 12.5°C | 6.2°C | -0.1°C | 24.3°C | -6.7°C | 33 mm | 68% | 1.3 m/s | 2.8 |
| 2020 🌧️ | 9.9°C | 3.7°C | -2.6°C | 23.1°C | -20.1°C | 68 mm | 72% | 1.5 m/s | 2.7 |
| 2019 ❄️ | 6.0°C | 0.3°C | -5.4°C | 18.6°C | -17.1°C | 47 mm | 72% | 1.4 m/s | 2.8 |
| 2018 | 10.4°C | 4.6°C | -1.2°C | 19.6°C | -6.5°C | 47 mm | 74% | 1.2 m/s | 2.8 |
| 2017 | 9.6°C | 3.4°C | -2.8°C | 19.3°C | -6.1°C | 33 mm | 68% | 1.5 m/s | 2.8 |
| 2016 | 11.2°C | 5.7°C | 0.2°C | 19.5°C | -6.4°C | 65 mm | 75% | 1.3 m/s | 2.3 |
| 2015 | 14.5°C | 8.0°C | 1.5°C | 24.9°C | -3.7°C | 27 mm | 67% | 1.2 m/s | 2.8 |
| 2014 | 14.2°C | 7.5°C | 0.9°C | 21.0°C | -4.9°C | 26 mm | 70% | 1.4 m/s | 2.9 |
| 2013 | 9.1°C | 3.0°C | -3.2°C | 18.6°C | -8.8°C | 40 mm | 73% | 1.2 m/s | 3.1 |
| 2012 | 10.0°C | 4.1°C | -1.8°C | 21.4°C | -7.1°C | 37 mm | 71% | 1.3 m/s | 2.7 |
| 2011 | 11.6°C | 6.0°C | 0.3°C | 26.3°C | -5.7°C | 47 mm | 73% | 1.3 m/s | 2.5 |
| 2010 | 13.6°C | 7.1°C | 0.6°C | 27.0°C | -4.8°C | 26 mm | 69% | 1.2 m/s | 3 |
| 2009 | 5.4°C | 0.4°C | -4.7°C | 19.3°C | -14.2°C | 65 mm | 78% | 1.4 m/s | 2.3 |
| 2008 | 11.1°C | 4.9°C | -1.3°C | 25.5°C | -11.4°C | 35 mm | 68% | 1.4 m/s | 2.8 |
| 2007 | 11.1°C | 4.8°C | -1.4°C | 21.0°C | -5.5°C | 40 mm | 70% | 1.3 m/s | 2.6 |
| 2006 | 9.4°C | 3.6°C | -2.3°C | 20.6°C | -12.5°C | 59 mm | 72% | 1.2 m/s | 2.8 |
| 2005 | 12.9°C | 6.5°C | 0.1°C | 20.3°C | -4.7°C | 42 mm | 72% | 1.1 m/s | 2.8 |
| 2004 | 11.4°C | 5.4°C | -0.6°C | 21.4°C | -5.3°C | 29 mm | 72% | 1.2 m/s | 3 |
| 2003 | 14.4°C | 7.5°C | 0.6°C | 24.4°C | -13.3°C | 25 mm | 57% | 1.5 m/s | 3.1 |
| 2002 | 8.8°C | 2.6°C | -3.7°C | 18.0°C | -14.5°C | 15 mm | 62% | 1.2 m/s | 3.2 |
| 2001 | 10.4°C | 4.3°C | -1.9°C | 25.1°C | -6.1°C | 36 mm | 66% | 1.5 m/s | 2.7 |
| 2000 | 11.5°C | 4.7°C | -2.0°C | 21.4°C | -6.5°C | 50 mm | 68% | 1.1 m/s | 3 |
| 1999 | 12.9°C | 5.9°C | -1.2°C | 22.7°C | -6.9°C | 18 mm | 60% | 1.3 m/s | 2.9 |
| 1998 | 12.0°C | 5.3°C | -1.3°C | 21.7°C | -5.5°C | 19 mm | 64% | 1.1 m/s | 2.8 |
| 1997 | 9.4°C | 3.7°C | -1.9°C | 24.4°C | -7.4°C | 55 mm | 75% | 1.4 m/s | 2.5 |
| 1996 | 10.6°C | 4.3°C | -2.0°C | 24.3°C | -12.1°C | 31 mm | 64% | 1.3 m/s | 3 |
| 1995 | 8.6°C | 2.9°C | -2.8°C | 21.0°C | -9.8°C | 37 mm | 71% | 1.5 m/s | 2.8 |
| 1994 | 9.9°C | 4.0°C | -1.9°C | 20.6°C | -5.8°C | 59 mm | 70% | 1.4 m/s | 2.6 |
| 1993 | 10.9°C | 4.7°C | -1.6°C | 23.7°C | -9.6°C | 36 mm | 71% | 1.2 m/s | 2.8 |
| 1992 | 12.7°C | 6.1°C | -0.6°C | 27.0°C | -6.6°C | 48 mm | 66% | 1.1 m/s | 2.7 |
| 1991 | 10.5°C | 3.9°C | -2.6°C | 24.5°C | -16.9°C | 24 mm | 59% | 1.4 m/s | 3.1 |
| 1990 | 10.2°C | 4.0°C | -2.1°C | 23.5°C | -6.3°C | 23 mm | 64% | 1.6 m/s | 2.6 |
| 1989 | 10.6°C | 4.4°C | -1.7°C | 20.1°C | -9.4°C | 30 mm | 68% | 1.3 m/s | 2.9 |
| 1988 🔥 | 15.7°C | 8.5°C | 1.3°C | 23.0°C | -7.0°C | 22 mm | 60% | 1.3 m/s | 3.1 |
| 1987 | 14.6°C | 6.7°C | -1.1°C | 25.3°C | -6.7°C | 3 mm | 49% | 1.1 m/s | 3.5 |
| 1986 | 13.3°C | 6.3°C | -0.8°C | 19.7°C | -6.6°C | 10 mm | 65% | 1.1 m/s | 3.1 |
| 1985 | 9.0°C | 2.7°C | -3.6°C | 18.6°C | -14.2°C | 36 mm | 72% | 1.6 m/s | 2.4 |
| 1984 | 8.4°C | 2.6°C | -3.1°C | 22.9°C | -12.4°C | 36 mm | 66% | 1.3 m/s | 2.9 |
| 1983 | 12.4°C | 5.5°C | -1.3°C | 18.5°C | -5.2°C | 30 mm | 71% | 1.1 m/s | — |
| 1982 | 10.0°C | 3.9°C | -2.1°C | 20.4°C | -6.2°C | 28 mm | 74% | 1.2 m/s | — |
| 1981 | 9.1°C | 3.3°C | -2.6°C | 20.5°C | -7.4°C | 40 mm | 71% | 1.2 m/s | — |
Actual recorded October data for each year, 1981–2025 — sourced from NASA POWER.
The average high in October is around 11.2°C with lows near -1.4°C (mean 4.9°C), based on 45 years of NASA POWER data.
October averages 36 mm of rainfall in Helena, about average for rainfall. The wettest on record was 68 mm in 2020.
The hottest October reached 27°C in 1992. The coldest dipped to -20.1°C in 2020.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average October temperatures have risen by about 3°C. Daytime highs moved from 9.8°C to 13°C and overnight lows from -2.5°C to 0.1°C over the same span.
October is close to Helena's year-round average and about average for rainfall, so plan for around 11.2°C daytime highs and -1.4°C at night.
Not quite — October is the 7th coolest month in Helena, averaging 4.9°C.
For October in Helena, pack warm layers and a jacket for chilly mornings, with typical highs of 11.2°C and lows of -1.4°C.
Relative humidity in October averages 68% — moderately humid.
Average wind speed in October is 1.3 m/s. The windiest October on record averaged 1.6 m/s (1985).
The wettest October on record was 2020 with 68 mm. On average, October sees 36 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 October, 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 October specifically, along with year-by-year records and how the month has changed over the decades.
