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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 mild 18°C (64°F). However, temperatures can fluctuate significantly, with minimums dipping to 2°C (36°F) and maximums soaring to 32°C (90°F). Expect about 85 mm (3.3 in) of rain spread over 11 days, and the average humidity sits at a warm 79%. Perfect weather for experiencing the rich culture and outdoor activities!

September Temperature in Alto

In September in Alto, the average temperature is 18°C (64°F). Maximum temperatures can reach up to 32°C (90°F), while minimums can drop as low as 2°C (36°F). This varied climate makes Alto an ideal destination for travelers seeking both warm and cool experiences.

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 18°C (64°F), with highs reaching up to 32°C (90°F) and lows dropping to around 2°C (36°F).
JanFebMarAprMayJunJulAugSepOctNovDec202134445869737064513628
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 total precipitation amount is 85 mm (3.3 in) over a span of 11 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 85 mm (3.3 inches) of precipitation spread over approximately 11 days.
JanFebMarAprMayJunJulAugSepOctNovDec4648599911610510498851054647
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 79%. With an average temperature of 18°C (64°F), this humidity feels like a warm, sticky embrace that can make outdoor activities more challenging but also creates a lush, vibrant atmosphere that's perfect for exploring local culture and scenery.

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 79%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec85%85%85%85%78%80%78%76%79%83%88%82%
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 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 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 7, which falls under the high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec34589101097532
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 Weather-7°C (20°F)46 mm (1.8 inches)85%moderate
February Weather-6°C (21°F)48 mm (1.9 inches)85%moderate
March Weather1°C (34°F)59 mm (2.3 inches)85%moderate
April Weather7°C (44°F)99 mm (3.9 inches)85%very high
May Weather14°C (58°F)116 mm (4.6 inches)78%very high
June Weather21°C (69°F)105 mm (4.1 inches)80%very high
July Weather23°C (74°F)104 mm (4.1 inches)78%very high
August Weather21°C (71°F)98 mm (3.9 inches)76%very high
September Weather18°C (64°F)85 mm (3.3 inches)79%high
October Weather10°C (51°F)105 mm (4.1 inches)83%moderate
November Weather2°C (36°F)46 mm (1.8 inches)88%moderate
December Weather-2°C (28°F)47 mm (1.9 inches)81%low

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