September Weather in McKinney, United States

Last updated: June 24, 2025

In September, the average temperature in McKinney, United States hovers around 26°C (79°F), with a minimum of 10°C (50°F) and a maximum that can soar to 37°C (99°F). Prepare for some rainy days, as the area typically experiences 98 mm (3.8 in) of precipitation over 8 days. With an average humidity of 65%, it's a humid yet warm time to visit!

September Temperature in McKinney

In September in McKinney, the average temperature is 26°C (79°F), with maximums reaching up to 37°C (99°F) and minimums dropping as low as 10°C (50°F). It's advisable to pack a mix of light clothing for the daytime and warmer layers for the cooler evenings.

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

The chart illustrates September temperature patterns in McKinney, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In McKinney, September typically has an average temperature of 26°C (79°F), with highs reaching up to 37°C (99°F) and lows dropping to around 10°C (50°F).

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

September Precipitation in McKinney

In McKinney in September, the precipitation amount is 98 mm (3.8 in) during a span of 8 days.

September Precipitation Trends in McKinney

The chart displays monthly precipitation patterns in McKinney, 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 McKinney, September typically receives around 98 mm (3.8 inches) of precipitation spread over approximately 8 days.

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

Choose your preferred precipitation unit

Millimeters (mm) Inches (in)

September Humidity in McKinney

In McKinney in September, humidity is 65%. With an average temperature of 26°C (79°F), this humidity feels like a warm, enveloping blanket, making travel quite sticky and uncomfortable.

September Average Humidity in McKinney

This chart illustrates the average monthly humidity levels in McKinney, 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 McKinney 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 McKinney

In McKinney in September, the maximum UV index reaches 10, which corresponds to a very high Exposure Category. With a time to burn of just 15 minutes, it's crucial to take precautions. For more detailed information, you can check the Hourly UV Index in McKinney.

Maximum UV Index Levels in McKinney for September

The chart shows the monthly maximum UV Index (UVI) for McKinney 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 McKinney typically reaches 10, which falls under the very high exposure category.

Data source: McKinney 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 McKinney Compares to Other Months

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

This table compares monthly weather conditions in McKinney, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
	Temperature	Precipitation	Humidity	UV
January Weather	8°C (46°F)	65 mm (2.6 inches)	80%	moderate
February Weather	9°C (48°F)	104 mm (4.1 inches)	79%	high
March Weather	15°C (59°F)	134 mm (5.3 inches)	78%	very high
April Weather	18°C (64°F)	144 mm (5.7 inches)	78%	very high
May Weather	23°C (73°F)	180 mm (7.1 inches)	81%	extreme
June Weather	27°C (81°F)	100 mm (4.0 inches)	78%	extreme
July Weather	29°C (84°F)	58 mm (2.3 inches)	73%	extreme
August Weather	29°C (84°F)	96 mm (3.8 inches)	66%	extreme
September Weather	26°C (79°F)	98 mm (3.8 inches)	65%	very high
October Weather	19°C (67°F)	157 mm (6.2 inches)	72%	very high
November Weather	13°C (56°F)	58 mm (2.3 inches)	82%	high
December Weather	10°C (51°F)	73 mm (2.9 inches)	87%	moderate