September Weather in Hopland, United States

Last updated: June 24, 2025

In Hopland, United States, the average temperature in September is a pleasant 21°C (70°F). However, temperatures can fluctuate significantly, with a minimum of 4°C (40°F) and soaring up to a maximum of 42°C (109°F). Visitors can expect minimal precipitation at just 3 mm (0.1 in) over the course of 1 day, coupled with an average humidity of 68%. Enjoy your stay while soaking up the diverse weather!

September Temperature in Hopland

In September in Hopland, the average temperature is 21°C (70°F), with maximums reaching up to 42°C (109°F) and minimums dropping as low as 4°C (40°F). This wide temperature range makes it essential for travelers to be prepared for both warm days and cooler evenings.

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

The chart illustrates September temperature patterns in Hopland, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Hopland, September typically has an average temperature of 21°C (70°F), with highs reaching up to 42°C (109°F) and lows dropping to around 4°C (40°F).

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

September Precipitation in Hopland

In Hopland in September, the precipitation amount is 3 mm (0.1 in) over the course of 1 day.

September Precipitation Trends in Hopland

The chart displays monthly precipitation patterns in Hopland, 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 Hopland, September typically receives around 3 mm (0.1 inches) of precipitation spread over approximately 1 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 Hopland

In Hopland in September humidity is 68%. With an average temperature of 21°C (70°F), this humidity feels like a warm embrace, making the air feel slightly heavy and sticky, which can be quite exhausting for travelers.

September Average Humidity in Hopland

This chart illustrates the average monthly humidity levels in Hopland, 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 Hopland is approximately 68%, 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 Hopland

In Hopland in September, the maximum UV index is 9, which corresponds to a very high Exposure Category. The time to burn is just 15 minutes, so it's essential to take precautions. For detailed information, you can check the Hourly UV Index in Hopland.

Maximum UV Index Levels in Hopland for September

The chart shows the monthly maximum UV Index (UVI) for Hopland 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 Hopland typically reaches 9, which falls under the very high exposure category.

Data source: Hopland 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 Hopland Compares to Other Months

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

This table compares monthly weather conditions in Hopland, 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)	157 mm (6.2 inches)	86%	moderate
February Weather	8°C (47°F)	165 mm (6.5 inches)	84%	moderate
March Weather	9°C (49°F)	119 mm (4.7 inches)	83%	high
April Weather	13°C (55°F)	60 mm (2.4 inches)	80%	very high
May Weather	16°C (61°F)	42 mm (1.7 inches)	80%	extreme
June Weather	21°C (70°F)	2 mm (0.1 inches)	76%	extreme
July Weather	24°C (76°F)	0 mm (0.0 inches)	70%	extreme
August Weather	24°C (76°F)	1 mm (0.0 inches)	66%	very high
September Weather	21°C (70°F)	3 mm (0.1 inches)	68%	very high
October Weather	16°C (61°F)	49 mm (1.9 inches)	72%	high
November Weather	11°C (52°F)	72 mm (2.9 inches)	84%	moderate
December Weather	7°C (46°F)	104 mm (4.1 inches)	84%	moderate