September Weather in Crystal City, United States

Last updated: June 24, 2025

In September, the average temperature in Crystal City, United States hovers around 29°C (84°F). Expect a range that dips to 14°C (58°F) at its coolest and soars to a sweltering 41°C (107°F) at its hottest. This month also sees about 118 mm (4.7 in) of precipitation spread over 8 days, with average humidity sitting comfortably at 65%.

September Temperature in Crystal City

In September in Crystal City, the average temperature is 29°C (84°F). Maximums can reach 41°C (107°F) and minimums can be as low as 14°C (58°F). Be prepared for hot days and cooler evenings while exploring the area.

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

The chart illustrates September temperature patterns in Crystal City, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Crystal City, September typically has an average temperature of 29°C (84°F), with highs reaching up to 41°C (107°F) and lows dropping to around 14°C (58°F).

Data source: Temperature data for Crystal City generated using information from the Copernicus Climate Change Service.

September Precipitation in Crystal City

In Crystal City in September, the precipitation amount is 118 mm (4.7 in) over the course of 8 days.

September Precipitation Trends in Crystal City

The chart displays monthly precipitation patterns in Crystal 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 Crystal City, September typically receives around 118 mm (4.7 inches) of precipitation spread over approximately 8 days.

Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.

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Millimeters (mm) Inches (in)

September Humidity in Crystal City

In Crystal City in September humidity is 65%. With average temperature 29°C (84°F), this humidity feels like a warm embrace, making outdoor activities comfortable yet requiring you to stay hydrated and take breaks in the shade.

September Average Humidity in Crystal City

This chart illustrates the average monthly humidity levels in Crystal 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 Crystal City is approximately 65%, offering insight into how humid the weather typically is during this month.

Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Crystal City

In Crystal 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 Crystal City.

Maximum UV Index Levels in Crystal City for September

The chart shows the monthly maximum UV Index (UVI) for Crystal 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 Crystal City typically reaches 11, which falls under the extreme exposure category.

Data source: Crystal 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 Crystal City Compares to Other Months

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

This table compares monthly weather conditions in Crystal City, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
	Temperature	Precipitation	Humidity	UV
January Weather	13°C (56°F)	21 mm (0.8 inches)	79%	moderate
February Weather	15°C (59°F)	30 mm (1.2 inches)	79%	very high
March Weather	21°C (69°F)	25 mm (1.0 inches)	74%	very high
April Weather	24°C (75°F)	58 mm (2.3 inches)	76%	extreme
May Weather	27°C (82°F)	101 mm (4.0 inches)	81%	extreme
June Weather	30°C (87°F)	37 mm (1.4 inches)	76%	extreme
July Weather	32°C (89°F)	40 mm (1.6 inches)	66%	extreme
August Weather	32°C (90°F)	39 mm (1.5 inches)	58%	extreme
September Weather	29°C (84°F)	118 mm (4.7 inches)	65%	extreme
October Weather	24°C (75°F)	63 mm (2.5 inches)	74%	very high
November Weather	18°C (64°F)	33 mm (1.3 inches)	81%	high
December Weather	15°C (59°F)	25 mm (1.0 inches)	86%	moderate