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September Weather in Alto, United States

Last updated: June 24, 2025

In September, the average temperature in Alto, United States is a pleasant 23°C (74°F), offering a delightful climate for outdoor activities. However, be prepared for some temperature variation, with minimums dipping to 10°C (50°F) and maximums soaring up to 35°C (95°F). Expect around 125 mm (4.9 in) of precipitation over 10 days, coupled with an average humidity level of 76%, ensuring a lush and vibrant atmosphere throughout the month.

September Temperature in Alto

In September in Alto, the average temperature is 23°C (74°F). Maximums can reach 35°C (95°F), while minimums can drop to as low as 10°C (50°F). Be prepared for warm days and cooler nights while enjoying all that Alto has to offer!

September Weather in Alto: Daily Temperature Highs, Lows, and Averages

The chart illustrates September temperature patterns in Alto, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Alto, September typically has an average temperature of 23°C (74°F), with highs reaching up to 35°C (95°F) and lows dropping to around 10°C (50°F).
JanFebMarAprMayJunJulAugSepOctNovDec444954616975787773645147
Data source: Temperature data for Alto 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 Alto

In Alto in September, the precipitation amount is 125 mm (4.9 in) spread over a period of 10 days.

September Precipitation Trends in Alto

The chart displays monthly precipitation patterns in Alto, 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 Alto, September typically receives around 125 mm (4.9 inches) of precipitation spread over approximately 10 days.
JanFebMarAprMayJunJulAugSepOctNovDec11516412913013311310213512616887146
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Alto

In Alto in September humidity is 76%. With an average temperature of 23°C (74°F), this humidity feels like a warm, thick blanket wrapping around you, making outdoor exploration feel a bit sluggish and requiring frequent breaks for hydration and respite from the heat.

September Average Humidity in Alto

This chart illustrates the average monthly humidity levels in Alto, 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 Alto is approximately 76%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec86%86%86%82%85%85%83%76%76%80%88%88%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Alto

In Alto in September, the maximum UV index is 9, which corresponds to a very high Exposure Category. The time to burn is just 15 minutes, so it's essential to take precautions. For detailed information, you can check the Hourly UV Index in Alto.

Maximum UV Index Levels in Alto for September

The chart shows the monthly maximum UV Index (UVI) for Alto 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 Alto typically reaches 9, which falls under the very high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec47811111111109864
Data source: Alto 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 Alto Compares to Other Months

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

This table compares monthly weather conditions in Alto, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather7°C (44°F)115 mm (4.5 inches)86%moderate
February Weather9°C (49°F)164 mm (6.5 inches)86%high
March Weather12°C (54°F)129 mm (5.1 inches)86%very high
April Weather16°C (61°F)130 mm (5.1 inches)82%extreme
May Weather21°C (70°F)132 mm (5.2 inches)85%extreme
June Weather24°C (75°F)112 mm (4.4 inches)85%extreme
July Weather26°C (79°F)102 mm (4.0 inches)83%extreme
August Weather25°C (78°F)135 mm (5.3 inches)76%very high
September Weather23°C (74°F)125 mm (4.9 inches)76%very high
October Weather18°C (65°F)168 mm (6.6 inches)80%very high
November Weather11°C (52°F)87 mm (3.4 inches)88%high
December Weather8°C (47°F)146 mm (5.7 inches)88%moderate

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