| Apple Tree Day | |  |
| Old Rock Day | | |
| Earth's Rotation Day | | |
| National Cut Your Energy Costs Day | | |
| National Houseplant Appreciation Day | | |
| World Snow Day | | |
| National Seed Swap Day | | |
| Observe The Weather Day | | |
| National Geographic Day | | |
| International Reducing CO2 Emissions Day | | |
| National Daisy Day | | |
| National Carnation Day | | |
| World Wetlands Day | | |
| National Hemp Day | | |
| Rose Day | | |
| Darwin Day | | |
| Pluto Day | | |
| Skip the Straw Day | | |
| National Groundwater Awareness Week | | |
| World Seagrass Day | | |
| World Wildlife Day | | |
| National Plant a Flower Day | | |
| Global Recycling Day | | |
| National Biodiesel Day | | |
| National Snowman Burning Day | | |
| International Day of Forests | | |
| World Water Day | | |
| National Near Miss Day | | |
| World Meteorological Day | | |
| Earth Hour | | |
| Weed Appreciation Day | | |
| Niagara Falls Runs Dry Day | | |
| National Cannabis Awareness Month | | |
| National Garden Month | | |
| National Find a Rainbow Day | | |
| Geologists’ Day | | |
| National Big Wind Day | | |
| Yuri's Night | | |
| Look up the Sky Day | | |
| National Gardening Day | | |
| National Look Up At The Sky Day | | |
| National Orchid Day | | |
| National Hanging Out Day | | |
| Earth Day | | |
| International Mother Earth Day | | |
| National DNA Day | | |
| International Chernobyl Disaster Remembrance Day | | |
| National Audubon Day | | |
| National Richter Scale Day | | |
| National Peace Rose Day | | |
| National Gardening Week | | |
| National Space Day | | |
| National Water Safety Month | | |
| National Wildfire Awareness Month | | |
| Herb Day | | |
| Wildfire Community Preparedness Day | | |
| World Naked Gardening Day | | |
| National Garden Meditation Day | | |
| National Astronaut Day | | |
| Iris Day | | |
| National Public Gardens Day | | |
| International Day Of Argania | | |
| Mother Ocean Day | | |
| International Day Of Plant Health | | |
| Bring Flowers To Someone Day | | |
| National Endangered Species Day | | |
| National Love a Tree Day | | |
| Plant A Lemon Tree Day | | |
| National May Ray Day | | |
| National Pick Strawberries Day | | |
| International Day for Biological Diversity | | |
| National Brown-Bag It Day | | |
| International Everest Day | | |
| Learn About Composting Day | | |
| National Water a Flower Day | | |
| International Mud Month | | |
| National Camping Month | | |
| National Great Outdoors Month | | |
| National Pollinators Month | | |
| National Rose Month | | |
| World Reef Awareness Day | | |
| Chimborazo Day | | |
| International Day For The Fight Against Illegal, Unreported And Unregulated Fishing | | |
| World Environment Day | | |
| National Caves And Karst Day | | |
| National Gardening Exercise Day | | |
| National Prairie Day | | |
| National Trails Day | | |
| World Oceans Day | | |
| National Red Rose Day | | |
| International Rock Day | | |
| National Weed Your Garden Day | | |
| Nature Photography Day | | |
| Arborist Appreciation Day | | |
| World Day to Combat Desertification and Drought | | |
| National Go Fishing Day | | |
| National Daylight Appreciation Day | | |
| World Rainforest Day | | |
| National Upcycling Day | | |
| National Orange Blossom Day | | |
| International Day Of The Tropics | | |
| International Mud Day | | |
| International Asteroid Day | | |
| National Meteor Watch Day | | |
| National Hemp Month | | |
| Plastic Free July | | |
| International Plastic Bag Free Day | | |
| Hop-a-Park Day | | |
| World Population Day | | |
| Paper Bag Day | | |
| International Moon Day | | |
| World Jump Day | | |
| Rain Day | | |
| National Water Quality Month | | |
| Pluto Demoted Day | | |
| Vesuvius Day | | |
| National Park Service Founders Day | | |
| National Secondhand Wardrobe Day | | |
| National Petroleum Day | | |
| International Day against Nuclear Tests | | |
| National Beach Day | | |
| Daffodil Day | | |
| National Wildlife Day | | |
| International Day Of Clean Air For Blue Skies | | |
| National Indoor Plant Week | | |
| Greenpeace Day | | |
| International Day for the Preservation of the Ozone Layer | | |
| World Water Monitoring Day | | |
| International Coastal Cleanup Day | | |
| National CleanUp Day | | |
| Car Free Day | | |
| Save The Koala Day | | |
| National Public Lands Day | | |
| National Crush a Can Day | | |
| World Rivers Day | | |
| World Space Week | | |
| World Habitat Day | | |
| International Day for Natural Disaster Reduction | | |
| National Fossil Day | | |
| World Cities Day | | |
| World Tsunami Awareness Day | | |
| International Day for Preventing the Exploitation of the Environment in War and Armed Conflict | | |
| America Recycles Day | | |
| Steve Irwin Day | | |
| National Take A Hike Day | | |
| GIS Day | | |
| National Camp Day | | |
| National Farm-City Week | | |
| Red Planet Day | | |
| National Give Space Day | | |
| World Wildlife Conservation Day | | |
| Skywarn Recognition Day | | |
| World Soil Day | | |
| International Mountain Day | | |
| Poinsettia Day | | |
| Falling Needles Family Fest Day | | |
