May Weather in Waterloo, United States

Last updated: June 24, 2025

In May, the average temperature in Waterloo, United States is a pleasant 20°C (68°F), with a minimum dipping to 6°C (44°F) and a maximum soaring to 39°C (103°F). The region experiences an average humidity of 71%, complemented by 20 mm (0.8 in) of precipitation over 2 days. Prepare to enjoy a mix of warm days and refreshing breezes!

May Temperature in Waterloo

In May in Waterloo, the average temperature is 20°C (68°F). Maximums can reach 39°C (103°F), while minimums can dip as low as 6°C (44°F). It's advisable to pack both light clothing for warm days and warmer layers for cooler nights during your travels.

May Weather in Waterloo: Daily Temperature Highs, Lows, and Averages

The chart illustrates May temperature patterns in Waterloo, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Waterloo, May typically has an average temperature of 20°C (68°F), with highs reaching up to 39°C (103°F) and lows dropping to around 6°C (44°F).

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

May Precipitation in Waterloo

In Waterloo in May, the precipitation amount is 20 mm (0.8 in) over the course of 2 days.

May Precipitation Trends in Waterloo

The chart displays monthly precipitation patterns in Waterloo, with values for each month alongside May’s data, which is highlighted for easy comparison. It shows the amount of precipitation, providing insights into how May’s conditions compare to those of other months. In Waterloo, May typically receives around 20 mm (0.8 inches) of precipitation spread over approximately 2 days.

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

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Millimeters (mm) Inches (in)

May Humidity in Waterloo

In Waterloo in May, humidity is 71%. With an average temperature of 20°C (68°F), this humidity feels like a warm, moist embrace that can quickly lead to discomfort for travelers. The air clings to your skin, making even short walks feel more strenuous, while reaching for a refreshing drink becomes essential to stay hydrated.

May Average Humidity in Waterloo

This chart illustrates the average monthly humidity levels in Waterloo, with May’s data highlighted for easy comparison. It shows the fluctuation in humidity throughout the year, helping you understand how conditions vary by season. In May, average humidity in Waterloo is approximately 71%, offering insight into how humid the weather typically is during this month.

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

May UV Index in Waterloo

In Waterloo in May, 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 Waterloo.

Maximum UV Index Levels in Waterloo for May

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

Data source: Waterloo May 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 May Weather in Waterloo Compares to Other Months

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

This table compares monthly weather conditions in Waterloo, showing how May’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
	Temperature	Precipitation	Humidity	UV
January Weather	10°C (50°F)	110 mm (4.3 inches)	82%	moderate
February Weather	11°C (52°F)	95 mm (3.7 inches)	84%	moderate
March Weather	13°C (56°F)	89 mm (3.5 inches)	82%	very high
April Weather	17°C (62°F)	44 mm (1.7 inches)	78%	very high
May Weather	20°C (68°F)	20 mm (0.8 inches)	71%	very high
June Weather	24°C (75°F)	2 mm (0.1 inches)	64%	extreme
July Weather	24°C (76°F)	0 mm (0.0 inches)	58%	extreme
August Weather	24°C (76°F)	0 mm (0.0 inches)	54%	very high
September Weather	22°C (72°F)	2 mm (0.1 inches)	55%	very high
October Weather	18°C (65°F)	30 mm (1.2 inches)	62%	high
November Weather	13°C (55°F)	47 mm (1.8 inches)	78%	moderate
December Weather	9°C (49°F)	95 mm (3.7 inches)	80%	moderate