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September Weather in Heron Lake, United States

Last updated: June 24, 2025

In September, the average temperature in Heron Lake, United States is a pleasant 18°C (65°F). During this month, temperatures can fluctuate, with minimums dipping to 3°C (38°F) and maxima reaching up to 32°C (90°F). Expect around 110 mm (4.3 in) of precipitation spread over 9 days, and be prepared for a humid experience, as the average humidity hovers around 75%.

September Temperature in Heron Lake

In September in Heron Lake, the average temperature is 18°C (65°F). Maximum temperatures can reach 32°C (90°F), while minimums can drop as low as 3°C (38°F). Be prepared for a range of weather conditions when traveling during this time.

September Weather in Heron Lake: Daily Temperature Highs, Lows, and Averages

The chart illustrates September temperature patterns in Heron Lake, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Heron Lake, September typically has an average temperature of 18°C (65°F), with highs reaching up to 32°C (90°F) and lows dropping to around 3°C (38°F).
JanFebMarAprMayJunJulAugSepOctNovDec181733435972747064483425
Data source: Temperature data for Heron Lake 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.

September Precipitation in Heron Lake

In Heron Lake in September, the precipitation amount is 110 mm (4.3 in) over the course of 9 days.

September Precipitation Trends in Heron Lake

The chart displays monthly precipitation patterns in Heron Lake, with values for each month alongside September’s data, which is highlighted for easy comparison. It shows the amount of precipitation, providing insights into how September’s conditions compare to those of other months. In Heron Lake, September typically receives around 110 mm (4.3 inches) of precipitation spread over approximately 9 days.
JanFebMarAprMayJunJulAugSepOctNovDec31316891125127102115110923141
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Heron Lake

In Heron Lake in September, humidity is 75%. With an average temperature of 18°C (65°F), this humidity feels like a warm, enveloping blanket that can make outdoor exploration feel a bit stifling, potentially leading to discomfort during travel activities.

September Average Humidity in Heron Lake

This chart illustrates the average monthly humidity levels in Heron Lake, with September’s data highlighted for easy comparison. It shows the fluctuation in humidity throughout the year, helping you understand how conditions vary by season. In September, average humidity in Heron Lake is approximately 75%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec80%84%75%79%74%81%82%80%75%77%85%83%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Heron Lake

In Heron Lake in September, the maximum UV index is 8, which corresponds to a very high Exposure Category. This means that the time to burn is only 15 minutes. For more detailed information, you can refer to the Hourly UV Index in Heron Lake.

Maximum UV Index Levels in Heron Lake for September

The chart shows the monthly maximum UV Index (UVI) for Heron Lake in September, 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 September, the maximum UV index in Heron Lake typically reaches 8, which falls under the very high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec35689111098533
Data source: Heron Lake September 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 September Weather in Heron Lake Compares to Other Months

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

This table compares monthly weather conditions in Heron Lake, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather-8°C (18°F)31 mm (1.2 inches)80%moderate
February Weather-8°C (17°F)31 mm (1.2 inches)84%moderate
March Weather1°C (34°F)68 mm (2.7 inches)75%high
April Weather6°C (44°F)91 mm (3.6 inches)79%very high
May Weather15°C (59°F)125 mm (4.9 inches)74%very high
June Weather22°C (72°F)127 mm (5.0 inches)81%extreme
July Weather23°C (74°F)102 mm (4.0 inches)82%very high
August Weather21°C (70°F)115 mm (4.5 inches)80%very high
September Weather18°C (65°F)110 mm (4.3 inches)75%very high
October Weather9°C (48°F)92 mm (3.6 inches)77%moderate
November Weather1°C (34°F)31 mm (1.2 inches)85%moderate
December Weather-4°C (25°F)41 mm (1.6 inches)83%moderate

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