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April Weather in Heidelberg, United States

Last updated: June 24, 2025

In Heidelberg, United States, the average temperature in April hovers around 18°C (65°F). Expect variations with a minimum of 2°C (37°F) and a maximum of 31°C (89°F). During this month, precipitation typically reaches 127 mm (5.0 in) over 8 days, contributing to an average humidity of 78%. Enjoy the diverse weather this month brings!

April Temperature in Heidelberg

In April in Heidelberg, the average temperature is 18°C (65°F). The maximum can reach 31°C (89°F), while the minimum can be as low as 2°C (37°F). Be prepared for a wide range of temperatures when traveling to Heidelberg this April.

April Weather in Heidelberg: Daily Temperature Highs, Lows, and Averages

The chart illustrates April temperature patterns in Heidelberg, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Heidelberg, April typically has an average temperature of 18°C (65°F), with highs reaching up to 31°C (89°F) and lows dropping to around 2°C (37°F).
JanFebMarAprMayJunJulAugSepOctNovDec495561657479818178705652
Data source: Temperature data for Heidelberg 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.

April Precipitation in Heidelberg

In Heidelberg in April, the precipitation amount is 127 mm (5.0 in) spread over 8 days.

April Precipitation Trends in Heidelberg

The chart displays monthly precipitation patterns in Heidelberg, with values for each month alongside April’s data, which is highlighted for easy comparison. It shows the amount of precipitation, providing insights into how April’s conditions compare to those of other months. In Heidelberg, April typically receives around 127 mm (5.0 inches) of precipitation spread over approximately 8 days.
JanFebMarAprMayJunJulAugSepOctNovDec110140121127137168137132979972133
Data source: Precipitation data for April generated using information from the Copernicus Climate Change Service.
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April Humidity in Heidelberg

In Heidelberg in April, humidity is 78%. With an average temperature of 18°C (65°F), this humidity feels like a warm, enveloping blanket, making travel quite muggy and potentially uncomfortable, as it can leave you feeling sticky and fatigued more quickly than usual.

April Average Humidity in Heidelberg

This chart illustrates the average monthly humidity levels in Heidelberg, with April’s data highlighted for easy comparison. It shows the fluctuation in humidity throughout the year, helping you understand how conditions vary by season. In April, average humidity in Heidelberg is approximately 78%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec82%80%80%78%73%71%79%78%80%76%83%87%
Data source: Humidity data for April generated using information from the Copernicus Climate Change Service.

April UV Index in Heidelberg

In Heidelberg in April, the maximum UV index reaches 11, which corresponds to an extreme Exposure Category. With a time to burn of just 10 minutes, it's essential to take precautions. For more details, you can check the Hourly UV Index in Heidelberg.

Maximum UV Index Levels in Heidelberg for April

The chart shows the monthly maximum UV Index (UVI) for Heidelberg in April, 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 April, the maximum UV index in Heidelberg typically reaches 11, which falls under the extreme exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec478111111111110864
Data source: Heidelberg April 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 April Weather in Heidelberg Compares to Other Months

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

This table compares monthly weather conditions in Heidelberg, showing how April’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather10°C (50°F)110 mm (4.3 inches)82%moderate
February Weather13°C (55°F)140 mm (5.5 inches)80%high
March Weather16°C (61°F)121 mm (4.7 inches)80%very high
April Weather18°C (65°F)127 mm (5.0 inches)78%extreme
May Weather23°C (74°F)137 mm (5.4 inches)73%extreme
June Weather26°C (79°F)168 mm (6.6 inches)71%extreme
July Weather27°C (81°F)137 mm (5.4 inches)79%extreme
August Weather27°C (81°F)132 mm (5.2 inches)78%extreme
September Weather26°C (78°F)97 mm (3.8 inches)80%very high
October Weather21°C (70°F)99 mm (3.9 inches)76%very high
November Weather13°C (56°F)72 mm (2.8 inches)83%high
December Weather11°C (53°F)133 mm (5.3 inches)87%moderate

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