October Weather in Helena, United States

Last updated: June 24, 2025

In October, the average temperature in Helena, United States hovers around 4°C (40°F). This month can bring extremes, with temperatures dipping as low as -21°C (-6°F) and soaring up to 26°C (80°F). Expect about 41 mm (1.6 in) of precipitation spread over 10 days, contributing to an average humidity of 72%.

October Temperature in Helena

In October in Helena, the average temperature is 4°C (40°F), with maximums reaching 26°C (80°F) and minimums dipping as low as -21°C (-6°F). Travelers should be prepared for a wide range of temperatures and pack accordingly.

October Weather in Helena: Daily Temperature Highs, Lows, and Averages

The chart illustrates October temperature patterns in Helena, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Helena, October typically has an average temperature of 4°C (40°F), with highs reaching up to 26°C (80°F) and lows dropping to around -21°C (-6°F).
JanFebMarAprMayJunJulAugSepOctNovDec191629364858666555393021
Data source: Temperature data for Helena generated using information from the Copernicus Climate Change Service.
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The average of daily temperatures (24 hours) calculated across all days in the month.

October Precipitation in Helena

In Helena in October, the precipitation amount is 41 mm (1.6 in) spread over 10 days.

October Precipitation Trends in Helena

The chart displays monthly precipitation patterns in Helena, with values for each month alongside October’s data, which is highlighted for easy comparison. It shows the amount of precipitation, providing insights into how October’s conditions compare to those of other months. In Helena, October typically receives around 41 mm (1.6 inches) of precipitation spread over approximately 10 days.
JanFebMarAprMayJunJulAugSepOctNovDec2351386788107313444413333
Data source: Precipitation data for October generated using information from the Copernicus Climate Change Service.
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October Humidity in Helena

In Helena in October, humidity is 72%. With an average temperature of 4°C (40°F), this humidity feels like an uncomfortable chill that seeps into your bones, making outdoor activities challenging for travelers unaccustomed to such damp conditions.

October Average Humidity in Helena

This chart illustrates the average monthly humidity levels in Helena, with October’s data highlighted for easy comparison. It shows the fluctuation in humidity throughout the year, helping you understand how conditions vary by season. In October, average humidity in Helena is approximately 72%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec87%88%83%78%76%78%77%71%68%72%84%91%
Data source: Humidity data for October generated using information from the Copernicus Climate Change Service.

October UV Index in Helena

In Helena in October, the maximum UV index reaches 5, which corresponds to a moderate Exposure Category. Under these conditions, the estimated time to burn is approximately 30 minutes. For more details, you can check the Hourly UV Index in Helena.

Maximum UV Index Levels in Helena for October

The chart shows the monthly maximum UV Index (UVI) for Helena in October, representing the highest UV radiation level. The UVI measures the intensity of ultraviolet radiation from the sun, indicating the potential risk of sunburn and UV-related health issues. In October, the maximum UV index in Helena typically reaches 5, which falls under the moderate exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec34689111098532
Data source: Helena October UVI data generated using information from the Copernicus Climate Change Service.

UV Risk Categories

  •  Extreme (11+): Avoid the sun, stay in shade.
  •  Very High (8-10): Limit sun exposure.
  •  High (6-7): Use SPF 30+ and protective clothing.
  •  Moderate (3-5): Midday shade recommended.
  •  Low (0-2): No protection needed.

How October Weather in Helena Compares to Other Months

Weather in Helena varies notably across the year, with each month offering distinct climate conditions. This page compares October’s weather to other months in Helena, focusing on differences in temperature, rainfall, humidity, and UV levels.

This table compares monthly weather conditions in Helena, showing how October’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather-7°C (20°F)23 mm (0.9 inches)87%moderate
February Weather-9°C (16°F)51 mm (2.0 inches)88%moderate
March Weather-2°C (29°F)38 mm (1.5 inches)83%high
April Weather2°C (36°F)67 mm (2.7 inches)78%very high
May Weather9°C (48°F)88 mm (3.5 inches)76%very high
June Weather14°C (58°F)107 mm (4.2 inches)78%extreme
July Weather19°C (67°F)31 mm (1.2 inches)77%very high
August Weather18°C (65°F)34 mm (1.3 inches)71%very high
September Weather13°C (55°F)44 mm (1.7 inches)68%very high
October Weather4°C (40°F)41 mm (1.6 inches)72%moderate
November Weather-1°C (30°F)33 mm (1.3 inches)84%moderate
December Weather-6°C (21°F)33 mm (1.3 inches)90%low

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