| Date(s) – may change every year, unless highlighted in bold – check websites for details: | Event (and organizing body): |
| 23rd December 2017 – 7th January 2018 | Festival of Winter Walks (Ramblers) |
| 2nd January – 23rd February 2018 | Big Schools Garden Watch (rspb) |
| 27th-28th January 2018 (last w/e in January) | Big Garden Bird Watch Weekend (rspb) |
| 2nd February 2018 | World Wetlands Day (Ramsar) |
| 14th-21st February 2018 | National Nest Box Week (British Trust for Ornithology) |
| 21st March 2018 | World Forestry Day (United National General Assembly) |
| 22nd March 2018 | World Water Day (United Nations Water) |
| 15th April 2018 (tbc) | Daffodil Sunday |
| 19th April 2018 | Primrose Day (after Benjamin Disraeli) |
| 22nd April 2018 | Earth Day (Earth Day Network) |
| 6th May 2018 (1st Sunday in May) | International Dawn Chorus Day |
| 1st – 31st May 2018 | Walk in the Woods Month (The Tree Council) |
| 1st – 31st May 2018 | National Walking Month (Living Streets, Pedestrians Association) |
| 22nd May 2018 | International Day for Biological Biodiversity (United Nations) |
| 30th May 2018 (last Weds in May) | International Otter Awareness Day |
| 12th – 27th May 2018 (tbc) | Be Nice to Nettles Week (CONE) |
| 29th May 2018 | Oak Apple Day |
| 1st – 7th June 2018 | National Volunteers Week (NCVO) |
| 2nd June 2018 (1st Saturday in June) | Butterfly Education & Awareness Day (Association for Butterflies) |
| 5th June 2018 | World Environment Day (United Nations) |
| 2nd June 2018 (1st Saturday in June) | Butterfly Education & Awareness Day (Butterfly Association) |
| 16th June 2018 | National Badger Day |
| 14th – 22nd July 2018 (tbc) | National Dragonfly Week (British Dragonfly Society) |
| 18th – 24th June 2018 (Biennial – not in 2019 etc.) | National Insect Week (Royal Entomological Society-biennial) |
| 7th July 2018 (first Saturday in July) | National Meadows Day (Plantlife) |
| 29th July 2018 (last Sunday in July) | International Bog Day (established by the Scottish Wildlife Trust) |
| 29th August 2018 | International Bat Night (UNEP EUROBATS) |
| 21st – 29th July 2018 | National Moth Week (Friends of East Brunswick Environ. Comm.) |
| 26th – 30th August 2018 | World Water Week (Stockholm International Water Institute) |
| 23rd September – 23rd October 2018 (from equinox) | Seed Gathering Season (The Tree Council) |
| 28th September 2018 | Forest Stewardship Council Friday (FSC) |
| 1st October 2018 (1st Monday in October) | World Habitat Day (United Nations) |
| 4th October 2018 | World Animal Day (Naturewatch Foundation) |
| 6th October 2018 | National Badger Day (The Badger Trust) |
| 8th October 2018 | UK Fungus Day (British Mycological Society) |
| 27th October 2018 (4th Saturday in October) | Make a Difference Day (TEGNA) |
| 27-28th October 2018 (last weekend in October) | Feed the Birds Day (rspb) |
| 24th November – 2nd December 2018 | National Tree Week (The Tree Council) |
| 27th November 2018 | Lancashire Day |
| 1st – 2nd December 2018 (1st full w/e in Dec.) | Tree Dressing Day (Common Ground) |
| 5th December 2018 | International Volunteer Day (United Nations) |
| 22nd December 2018 – 6th January 2018 (tbc) | Festival of Winter Walks (Ramblers) |