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May Weather in Waterloo, United States

Last updated: June 24, 2025

In May, the average temperature in Waterloo, United States is a mild 14°C (58°F). However, temperatures can vary significantly, with lows reaching -1°C (30°F) and highs soaring up to 33°C (91°F). Visitors should also prepare for 116 mm (4.6 in) of precipitation spread over about 15 days, contributing to an average humidity level of 82%.

May Temperature in Waterloo

In May in Waterloo, the average temperature is 14°C (58°F), with maximums reaching 33°C (91°F) and minimums dropping as low as -1°C (30°F). Be prepared for a wide range of temperatures, making it essential to pack layers for 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 14°C (58°F), with highs reaching up to 33°C (91°F) and lows dropping to around -1°C (30°F).
JanFebMarAprMayJunJulAugSepOctNovDec272935465867737164544032
Data source: Temperature data for Waterloo generated using information from the Copernicus Climate Change Service.
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The average of daily temperatures (24 hours) calculated across all days in the month.

May Precipitation in Waterloo

In Waterloo in May, the total precipitation amount is 116 mm (4.6 in), occurring over a span of 15 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 116 mm (4.6 inches) of precipitation spread over approximately 15 days.
JanFebMarAprMayJunJulAugSepOctNovDec898881119116861531088215497101
Data source: Precipitation data for May generated using information from the Copernicus Climate Change Service.
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May Humidity in Waterloo

In Waterloo in May, humidity is 82%. With an average temperature of 14°C (58°F), this humidity feels like a heavy blanket wrapping around you, making travel uncomfortable and sticky.

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 82%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec90%90%87%88%82%79%78%76%78%84%89%86%
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.
JanFebMarAprMayJunJulAugSepOctNovDec24681010997632
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.
 TemperaturePrecipitationHumidityUV
January Weather-3°C (27°F)89 mm (3.5 inches)90%low
February Weather-2°C (29°F)88 mm (3.5 inches)90%moderate
March Weather2°C (35°F)81 mm (3.2 inches)87%high
April Weather8°C (46°F)119 mm (4.7 inches)88%very high
May Weather14°C (58°F)116 mm (4.6 inches)82%very high
June Weather20°C (67°F)86 mm (3.4 inches)79%very high
July Weather23°C (73°F)153 mm (6.0 inches)78%very high
August Weather22°C (72°F)108 mm (4.3 inches)76%very high
September Weather18°C (65°F)82 mm (3.2 inches)78%high
October Weather12°C (55°F)154 mm (6.1 inches)84%high
November Weather4°C (40°F)97 mm (3.8 inches)89%moderate
December Weather0°C (33°F)101 mm (4.0 inches)86%low

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