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September Weather in Johnson City, United States

Last updated: June 24, 2025

In September, the average temperature in Johnson City, United States hovers around 26°C (78°F). Expect a range from a cool 9°C (49°F) to a scorching 37°C (100°F). With an average humidity of 66%, the atmosphere can feel quite moist, especially during the 10 days where 99 mm (3.9 in) of precipitation is recorded.

September Temperature in Johnson City

In September in Johnson City, the average temperature is 26°C (78°F), with maximums reaching up to 37°C (100°F) and minimums dropping as low as 9°C (49°F). This makes it an ideal time for travelers seeking a warm climate while still enjoying cooler evenings.

September Weather in Johnson City: Daily Temperature Highs, Lows, and Averages

The chart illustrates September temperature patterns in Johnson City, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Johnson City, September typically has an average temperature of 26°C (78°F), with highs reaching up to 37°C (100°F) and lows dropping to around 9°C (49°F).
JanFebMarAprMayJunJulAugSepOctNovDec505262677581848478695954
Data source: Temperature data for Johnson City 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 Johnson City

In Johnson City in September, the total precipitation amount is 99 mm (3.9 in) spread over a period of 10 days.

September Precipitation Trends in Johnson City

The chart displays monthly precipitation patterns in Johnson City, 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 Johnson City, September typically receives around 99 mm (3.9 inches) of precipitation spread over approximately 10 days.
JanFebMarAprMayJunJulAugSepOctNovDec4662657114073578199953346
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Johnson City

In Johnson City in September, humidity is 66%. With an average temperature of 26°C (78°F), this humidity feels like a warm, sultry embrace that can be slightly stifling for traveling, making you crave cool breezes and shaded spots to relax and rehydrate.

September Average Humidity in Johnson City

This chart illustrates the average monthly humidity levels in Johnson City, 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 Johnson City is approximately 66%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec78%78%77%78%82%78%69%63%66%73%84%87%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Johnson City

In Johnson City in September, the maximum UV index reaches 11, which corresponds to an extreme Exposure Category. With a time to burn of just 10 minutes, it's essential to take precautions. For more details, you can check the Hourly UV Index in Johnson City.

Maximum UV Index Levels in Johnson City for September

The chart shows the monthly maximum UV Index (UVI) for Johnson City 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 Johnson City typically reaches 11, which falls under the extreme exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec579111112121111965
Data source: Johnson City 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 Johnson City Compares to Other Months

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

This table compares monthly weather conditions in Johnson City, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather10°C (50°F)46 mm (1.8 inches)78%moderate
February Weather11°C (52°F)62 mm (2.4 inches)78%high
March Weather17°C (62°F)65 mm (2.6 inches)77%very high
April Weather20°C (67°F)71 mm (2.8 inches)78%extreme
May Weather24°C (75°F)140 mm (5.5 inches)82%extreme
June Weather27°C (81°F)73 mm (2.9 inches)78%extreme
July Weather29°C (84°F)57 mm (2.2 inches)69%extreme
August Weather29°C (84°F)81 mm (3.2 inches)63%extreme
September Weather26°C (78°F)99 mm (3.9 inches)66%extreme
October Weather20°C (69°F)95 mm (3.7 inches)73%very high
November Weather15°C (59°F)33 mm (1.3 inches)84%high
December Weather12°C (54°F)46 mm (1.8 inches)87%moderate

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