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May Weather in Mattoon, United States

Last updated: August 27, 2025

In May, the average temperature in Mattoon, United States hovers around 19°C (66°F). Expect a range where the minimum can dip to 1°C (34°F) and the maximum can soar up to 35°C (95°F). Be prepared for precipitation, averaging 135 mm (5.3 in) over about 13 days, alongside an average humidity of 80%.

May Temperature in Mattoon

In May in Mattoon, the average temperature is 19°C (66°F). The maximum can reach 35°C (95°F), and the minimum can be as low as 1°C (34°F). This range makes it a versatile destination for travelers, allowing for both warm afternoons and cool evenings.

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

The chart illustrates May temperature patterns in Mattoon, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Mattoon, May typically has an average temperature of 19°C (66°F), with highs reaching up to 35°C (95°F) and lows dropping to around 1°C (34°F).
JanFebMarAprMayJunJulAugSepOctNovDec303344536675787471584237
Data source: Temperature data for Mattoon 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 Mattoon

In Mattoon in May, the precipitation amount is 135 mm (5.3 in) over the course of 13 days.

May Precipitation Trends in Mattoon

The chart displays monthly precipitation patterns in Mattoon, 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 Mattoon, May typically receives around 135 mm (5.3 inches) of precipitation spread over approximately 13 days.
JanFebMarAprMayJunJulAugSepOctNovDec7879125117135110116123671158965
Data source: Precipitation data for May generated using information from the Copernicus Climate Change Service.
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May Humidity in Mattoon

In Mattoon in May humidity is 80%. With an average temperature of 19°C (66°F), this humidity feels like a warm, thick blanket wrapping around you, making outdoor activities feel more strenuous and sticky, which can ultimately dampen the experience of traveling.

May Average Humidity in Mattoon

This chart illustrates the average monthly humidity levels in Mattoon, 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 Mattoon is approximately 80%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec84%82%84%83%80%83%82%83%79%79%88%87%
Data source: Humidity data for May generated using information from the Copernicus Climate Change Service.

May UV Index in Mattoon

In Mattoon 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 Mattoon.

Maximum UV Index Levels in Mattoon for May

The chart shows the monthly maximum UV Index (UVI) for Mattoon 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 Mattoon typically reaches 10, which falls under the very high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec356910111098643
Data source: Mattoon 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 Mattoon Compares to Other Months

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

This table compares monthly weather conditions in Mattoon, showing how May’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather-1°C (30°F)78 mm (3.1 inches)84%moderate
February Weather1°C (33°F)79 mm (3.1 inches)82%moderate
March Weather7°C (44°F)125 mm (4.9 inches)84%high
April Weather12°C (53°F)117 mm (4.6 inches)83%very high
May Weather19°C (66°F)135 mm (5.3 inches)80%very high
June Weather24°C (76°F)110 mm (4.3 inches)83%extreme
July Weather25°C (78°F)116 mm (4.6 inches)82%very high
August Weather24°C (75°F)123 mm (4.8 inches)82%very high
September Weather21°C (71°F)67 mm (2.6 inches)79%very high
October Weather14°C (58°F)115 mm (4.5 inches)79%high
November Weather6°C (42°F)89 mm (3.5 inches)88%moderate
December Weather3°C (37°F)65 mm (2.6 inches)87%moderate

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