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September Weather in Ilwaco, United States

Last updated: June 24, 2025

In September, the average temperature in Ilwaco, United States hovers around 15°C (60°F), with a minimum of 10°C (51°F) and a pleasant maximum of 24°C (75°F). Expect about 84 mm (3.3 in) of precipitation over roughly 10 days, contributing to an average humidity level of 74%. Whether you're exploring the outdoors or enjoying local culture, make sure to prepare for a variety of weather conditions!

September Temperature in Ilwaco

In September, in Ilwaco, the average temperature is 15°C (60°F). The maximum can reach 24°C (75°F), and the minimum can be as low as 10°C (51°F). This pleasant climate makes Ilwaco an ideal destination for outdoor activities and exploration.

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

The chart illustrates September temperature patterns in Ilwaco, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Ilwaco, September typically has an average temperature of 15°C (60°F), with highs reaching up to 24°C (75°F) and lows dropping to around 10°C (51°F).
JanFebMarAprMayJunJulAugSepOctNovDec464446505457596160555046
Data source: Temperature data for Ilwaco 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 Ilwaco

In Ilwaco in September, the precipitation amount is 84 mm (3.3 in) over a span of 10 days.

September Precipitation Trends in Ilwaco

The chart displays monthly precipitation patterns in Ilwaco, 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 Ilwaco, September typically receives around 84 mm (3.3 inches) of precipitation spread over approximately 10 days.
JanFebMarAprMayJunJulAugSepOctNovDec2421931611326659192184156249248
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Ilwaco

In Ilwaco in September humidity is 74%. With an average temperature of 15°C (60°F), this humidity feels like a warm embrace that can make outdoor activities feel slightly stifling, so travelers should be prepared to hydrate frequently and take breaks in the shade.

September Average Humidity in Ilwaco

This chart illustrates the average monthly humidity levels in Ilwaco, 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 Ilwaco is approximately 74%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec86%84%85%83%84%84%82%73%74%83%86%87%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Ilwaco

In Ilwaco 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 Ilwaco.

Maximum UV Index Levels in Ilwaco for September

The chart shows the monthly maximum UV Index (UVI) for Ilwaco 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 Ilwaco typically reaches 7, which falls under the high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec235699987532
Data source: Ilwaco 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 Ilwaco Compares to Other Months

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

This table compares monthly weather conditions in Ilwaco, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather8°C (47°F)242 mm (9.5 inches)86%low
February Weather7°C (45°F)193 mm (7.6 inches)84%moderate
March Weather8°C (47°F)161 mm (6.3 inches)85%moderate
April Weather10°C (50°F)132 mm (5.2 inches)83%high
May Weather12°C (54°F)66 mm (2.6 inches)84%very high
June Weather14°C (58°F)58 mm (2.3 inches)84%very high
July Weather15°C (60°F)19 mm (0.8 inches)82%very high
August Weather16°C (61°F)20 mm (0.8 inches)73%very high
September Weather15°C (60°F)84 mm (3.3 inches)74%high
October Weather13°C (55°F)156 mm (6.1 inches)83%moderate
November Weather10°C (51°F)249 mm (9.8 inches)86%moderate
December Weather8°C (47°F)248 mm (9.8 inches)87%low

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