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May Weather in Lewiston, United States

Last updated: June 24, 2025

In May, the average temperature in Lewiston, United States hovers around 14°C (58°F). Expect a minimum of 1°C (34°F) and a maximum of 32°C (89°F) during this period. While you enjoy the mild weather, be prepared for 47 mm (1.8 in) of precipitation over approximately 7 days, and anticipate an average humidity of 77%.

May Temperature in Lewiston

In May in Lewiston, the average temperature is 14°C (58°F), with maximums reaching 32°C (89°F) and minimums dipping as low as 1°C (34°F). It's advisable to pack layers to stay comfortable during your travels.

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

The chart illustrates May temperature patterns in Lewiston, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Lewiston, May typically has an average temperature of 14°C (58°F), with highs reaching up to 32°C (89°F) and lows dropping to around 1°C (34°F).
JanFebMarAprMayJunJulAugSepOctNovDec323341495866757564504033
Data source: Temperature data for Lewiston 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 Lewiston

In Lewiston in May, the precipitation amount is 47 mm (1.8 in) during a span of 7 days.

May Precipitation Trends in Lewiston

The chart displays monthly precipitation patterns in Lewiston, 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 Lewiston, May typically receives around 47 mm (1.8 inches) of precipitation spread over approximately 7 days.
JanFebMarAprMayJunJulAugSepOctNovDec5895645147283822526574
Data source: Precipitation data for May generated using information from the Copernicus Climate Change Service.
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May Humidity in Lewiston

In Lewiston in May, humidity is 77%. With an average temperature of 14°C (58°F), this humidity feels like a warm blanket wrapping around you, making traveling feel sticky and heavy, yet still manageable as you explore the sights.

May Average Humidity in Lewiston

This chart illustrates the average monthly humidity levels in Lewiston, 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 Lewiston is approximately 77%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec89%89%87%84%78%78%77%64%62%79%87%90%
Data source: Humidity data for May generated using information from the Copernicus Climate Change Service.

May UV Index in Lewiston

In Lewiston 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 Lewiston.

Maximum UV Index Levels in Lewiston for May

The chart shows the monthly maximum UV Index (UVI) for Lewiston 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 Lewiston typically reaches 9, which falls under the very high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec24689101097532
Data source: Lewiston 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 Lewiston Compares to Other Months

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

This table compares monthly weather conditions in Lewiston, showing how May’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather0°C (32°F)58 mm (2.3 inches)89%low
February Weather1°C (33°F)95 mm (3.7 inches)89%moderate
March Weather5°C (41°F)64 mm (2.5 inches)87%high
April Weather9°C (49°F)51 mm (2.0 inches)84%very high
May Weather14°C (58°F)47 mm (1.8 inches)77%very high
June Weather19°C (66°F)28 mm (1.1 inches)78%very high
July Weather24°C (76°F)3 mm (0.1 inches)77%very high
August Weather24°C (75°F)8 mm (0.3 inches)64%very high
September Weather18°C (64°F)22 mm (0.9 inches)62%high
October Weather10°C (50°F)52 mm (2.1 inches)79%moderate
November Weather4°C (40°F)65 mm (2.6 inches)87%moderate
December Weather1°C (33°F)74 mm (2.9 inches)90%low

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