nomadseason

September Weather in Clear Lake, United States

Last updated: June 24, 2025

In Clear Lake, United States, the average temperature in September hovers around 17°C (63°F), offering a pleasant climate for outdoor activities. Temperatures can range from a chilly 1°C (33°F) to a warm 32°C (90°F), so be prepared for varying conditions. Expect around 102 mm (4.0 in) of precipitation over 10 days, contributing to an average humidity of 80% that keeps the air refreshingly crisp.

September Temperature in Clear Lake

In September in Clear Lake, the average temperature is 17°C (63°F), with maximums reaching as high as 32°C (90°F) and minimums dropping to as low as 1°C (33°F). This variation makes it an ideal time for travelers to enjoy a range of outdoor activities, from warm sunny days to cooler evenings.

September Weather in Clear Lake: Daily Temperature Highs, Lows, and Averages

The chart illustrates September temperature patterns in Clear Lake, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Clear Lake, September typically has an average temperature of 17°C (63°F), with highs reaching up to 32°C (90°F) and lows dropping to around 1°C (33°F).
JanFebMarAprMayJunJulAugSepOctNovDec151632425769726962473222
Data source: Temperature data for Clear Lake generated using information from the Copernicus Climate Change Service.
Choose your preferred temperature unit
The average of daily temperatures (24 hours) calculated across all days in the month.

September Precipitation in Clear Lake

In Clear Lake in September, the total precipitation amount is 102 mm (4.0 in) falling over the course of 10 days.

September Precipitation Trends in Clear Lake

The chart displays monthly precipitation patterns in Clear Lake, 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 Clear Lake, September typically receives around 102 mm (4.0 inches) of precipitation spread over approximately 10 days.
JanFebMarAprMayJunJulAugSepOctNovDec283956901351101051251021014160
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
Choose your preferred precipitation unit

September Humidity in Clear Lake

In Clear Lake in September humidity is 80%. With an average temperature of 17°C (63°F), this humidity feels like you're walking through a thick, warm blanket, making travel feel slightly stifling and requiring frequent breaks to stay comfortable.

September Average Humidity in Clear Lake

This chart illustrates the average monthly humidity levels in Clear Lake, 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 Clear Lake is approximately 80%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec88%89%86%85%79%80%80%78%80%84%89%85%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Clear Lake

In Clear Lake 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 Clear Lake.

Maximum UV Index Levels in Clear Lake for September

The chart shows the monthly maximum UV Index (UVI) for Clear Lake 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 Clear Lake typically reaches 7, which falls under the high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec2457910997532
Data source: Clear Lake 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 Clear Lake Compares to Other Months

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

This table compares monthly weather conditions in Clear Lake, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather-9°C (16°F)28 mm (1.1 inches)88%low
February Weather-9°C (16°F)39 mm (1.5 inches)89%moderate
March Weather0°C (32°F)56 mm (2.2 inches)86%moderate
April Weather6°C (42°F)90 mm (3.5 inches)85%high
May Weather14°C (58°F)135 mm (5.3 inches)79%very high
June Weather21°C (69°F)110 mm (4.3 inches)80%very high
July Weather22°C (73°F)105 mm (4.1 inches)80%very high
August Weather20°C (69°F)125 mm (4.9 inches)78%very high
September Weather17°C (63°F)102 mm (4.0 inches)80%high
October Weather8°C (47°F)101 mm (4.0 inches)84%moderate
November Weather0°C (32°F)41 mm (1.6 inches)89%moderate
December Weather-6°C (22°F)60 mm (2.3 inches)85%low

Compare Clear Lake's Climate with Cities Worldwide