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May Weather in Waterloo, United States

Last updated: June 24, 2025

In Waterloo, United States, the average temperature in May hovers around 15°C (59°F), but be prepared for a range; the minimum can plummet to -1°C (30°F), while the maximum can soar to 34°C (93°F). During this time, expect 125 mm (4.9 in) of precipitation over roughly 13 days, accompanied by an average humidity of 78%.

May Temperature in Waterloo

In May in Waterloo, the average temperature is 15°C (59°F). Maximums can reach 34°C (93°F), while minimums can drop as low as -1°C (30°F). Be prepared for a wide range of temperatures while traveling during this time.

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 15°C (59°F), with highs reaching up to 34°C (93°F) and lows dropping to around -1°C (30°F).
JanFebMarAprMayJunJulAugSepOctNovDec212235465970747165513629
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 125 mm (4.9 in), occurring over a span of 13 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 125 mm (4.9 inches) of precipitation spread over approximately 13 days.
JanFebMarAprMayJunJulAugSepOctNovDec515157101125114102961021154346
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 78%. With an average temperature of 15°C (59°F), this humidity feels like a warm, enveloping blanket that clings to your skin, making outdoor activities a bit more tiring and requiring frequent breaks for hydration as you explore the area.

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 78%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec85%85%85%85%78%80%78%76%79%83%88%82%
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 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 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 9, which falls under the very high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec34589101098532
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-6°C (22°F)51 mm (2.0 inches)85%moderate
February Weather-5°C (22°F)51 mm (2.0 inches)85%moderate
March Weather2°C (36°F)57 mm (2.3 inches)85%moderate
April Weather8°C (46°F)100 mm (4.0 inches)85%very high
May Weather15°C (59°F)125 mm (4.9 inches)78%very high
June Weather21°C (70°F)114 mm (4.5 inches)80%very high
July Weather23°C (75°F)102 mm (4.0 inches)78%very high
August Weather22°C (71°F)96 mm (3.8 inches)76%very high
September Weather18°C (65°F)102 mm (4.0 inches)79%very high
October Weather11°C (51°F)115 mm (4.5 inches)83%moderate
November Weather2°C (37°F)43 mm (1.7 inches)88%moderate
December Weather-2°C (29°F)46 mm (1.8 inches)81%low

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