3 - World Aquatic Animal Day

4 - National Dark-Sky Week

7 - International Beaver Day

8 - Zoo Lovers Day

17 - Bat Appreciation Day

22 - Earth Day

26 - National Healthy Schools Day

27 - World Tapir Day

29 - Day of Remembrance for all Victims of Chemical Warfare

18-22 - Green Office Week

19-23 - Turn Climate Crisis Awareness and Action Week 

19-27 - National Park Week

20-26 - Dark Sky Week

Last Friday of April - Arbor Day