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September Weather in Saint Johnsbury, United States

Last updated: June 24, 2025

In Saint Johnsbury, United States, the average temperature in September hovers around 15°C (60°F). However, temperatures can vary significantly, with a minimum of -5°C (23°F) and a maximum reaching 30°C (86°F). Expect some rain, as 64 mm (2.5 in) of precipitation typically falls over 8 days, while the air maintains an average humidity of 77%.

September Temperature in Saint Johnsbury

In September in Saint Johnsbury, the average temperature is 15°C (60°F). Maximums can reach 30°C (86°F), while minimums can drop to as low as -5°C (23°F). Be prepared for a wide range of temperatures during your travels to Saint Johnsbury this September.

September Weather in Saint Johnsbury: Daily Temperature Highs, Lows, and Averages

The chart illustrates September temperature patterns in Saint Johnsbury, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Saint Johnsbury, September typically has an average temperature of 15°C (60°F), with highs reaching up to 30°C (86°F) and lows dropping to around -5°C (23°F).
JanFebMarAprMayJunJulAugSepOctNovDec182128425463686659483323
Data source: Temperature data for Saint Johnsbury 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 Saint Johnsbury

In Saint Johnsbury in September, the precipitation amount is 64 mm (2.5 in) over the course of 8 days.

September Precipitation Trends in Saint Johnsbury

The chart displays monthly precipitation patterns in Saint Johnsbury, 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 Saint Johnsbury, September typically receives around 64 mm (2.5 inches) of precipitation spread over approximately 8 days.
JanFebMarAprMayJunJulAugSepOctNovDec8078691109598106886413910385
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Saint Johnsbury

In Saint Johnsbury in September, humidity is 77%. With an average temperature of 15°C (60°F), this humidity feels like you're wading through a warm, heavy blanket, making travel feel more exhausting and sticky than usual.

September Average Humidity in Saint Johnsbury

This chart illustrates the average monthly humidity levels in Saint Johnsbury, 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 Saint Johnsbury is approximately 77%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec91%89%85%84%78%72%75%74%77%85%86%85%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Saint Johnsbury

In Saint Johnsbury in September, the maximum UV index is 7, which corresponds to the high Exposure Category. This means that the time to burn is approximately 25 minutes. For more detailed information, you can check the Hourly UV Index in Saint Johnsbury.

Maximum UV Index Levels in Saint Johnsbury for September

The chart shows the monthly maximum UV Index (UVI) for Saint Johnsbury 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 Saint Johnsbury typically reaches 7, which falls under the high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec2458910997532
Data source: Saint Johnsbury 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 Saint Johnsbury Compares to Other Months

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

This table compares monthly weather conditions in Saint Johnsbury, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather-8°C (18°F)80 mm (3.1 inches)91%low
February Weather-6°C (21°F)78 mm (3.1 inches)89%moderate
March Weather-2°C (29°F)69 mm (2.7 inches)85%moderate
April Weather5°C (42°F)110 mm (4.3 inches)84%very high
May Weather12°C (55°F)95 mm (3.7 inches)78%very high
June Weather17°C (63°F)98 mm (3.9 inches)72%very high
July Weather20°C (69°F)106 mm (4.2 inches)75%very high
August Weather19°C (67°F)88 mm (3.5 inches)74%very high
September Weather15°C (60°F)64 mm (2.5 inches)77%high
October Weather9°C (48°F)138 mm (5.5 inches)85%moderate
November Weather0°C (33°F)103 mm (4.0 inches)86%moderate
December Weather-5°C (23°F)85 mm (3.3 inches)85%low

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