Sources

References and inspiration for the 72 microseasons

About the 72 Microseasons

The concept of 72 microseasons originates from the ancient Japanese calendar system, which divides the year into 72 distinct periods based on subtle changes in nature. Each microseason lasts approximately 5 days and reflects the seasonal transitions observed in the natural world.

Pacific Northwest Adaptation

The microseasons presented here have been adapted to reflect the unique climate, flora, and fauna of the Pacific Northwest region, capturing the subtle rhythms of nature specific to this beautiful corner of the world.

Pacific Northwest 72 Microseasons - Source Documentation

Comprehensive research sources organized by topic to support the development and documentation of the Pacific Northwest 72 Microseasons calendar.

PHENOLOGY MONITORING & RESEARCH PROGRAMS

University of Washington

Cherry Tree Phenology Project - 8 years documenting 107+ cherry trees at UW campus
https://explorewashingtonstate.com/uw-cherry-blossoms-marlee-theil/

Salal (May-June bloom) - Information integrated from Native Plants PNW sources

Fireweed (June-September)
https://www.wildflower.org/plants/result.php?id_plant=chan9
https://sparrowhawknativeplants.com/products/fireweed

General Pacific Northwest Gardening Calendar
https://yardngardenland.com/calendar/
https://www.plantingguides.com/pacific-northwest-planting-calendar/

AMPHIBIANS & BREEDING PHENOLOGY

Pacific Tree Frog (January-February breeding peak)
https://wdfw.wa.gov/species-habitats/species/pseudacris-regilla
https://en.wikipedia.org/wiki/Pacific_tree_frog
https://animalia.bio/pacific-tree-frog
https://kingcounty.gov/en/legacy/services/environment/animals-and-plants/biodiversity/defining-biodiversity/species-of-interest/herps/treefrog
https://kingcounty.gov/en/dept/dnrp/nature-recreation/environment-ecology-conservation/wildlife/biodiversity/reptiles-amphibians-fish
https://friendsofedgewood.org/pacific-treefrog
https://www.dfw.state.or.us/wildlife/living_with/docs/LWW_Pacific_Treefrog_final.pdf

Roughskin Newt (February-April breeding)
https://wdfw.wa.gov/species-habitats/species/taricha-granulosa

Northwestern Salamander (February-April low elevations)
https://www.burkemuseum.org/collections-and-research/biology/herpetology/amphibians-reptiles-washington/northwestern-salamander

Northern Red-legged Frog
https://wdfw.wa.gov/species-habitats/species/rana-aurora

INSECTS & POLLINATORS

Mason Bees (March emergence)
https://extension.oregonstate.edu/catalog/pub/em-9130-nurturing-mason-bees-your-backyard-western-oregon
https://extension.oregonstate.edu/sites/extd8/files/documents/12281/masonbee.pdf
https://news.oregonstate.edu/news/mason-bees-go-work-early-season-honey-bees-emerge

Mourning Cloak Butterfly (Late March emergence)
https://wildadirondacks.org/adirondack-butterflies-mourning-cloak-nymphalis-antiopa.html
http://www.pollinatorconservationassociation.org/mourning-cloak.html

Western Tiger Swallowtail & Other Butterflies (April-September)
http://www.raisingbutterflies.org/basics-for-beginners-pacific-n/
https://www.heraldnet.com/news/yellow-butterflies-blossom-throughout-evergreen-state/
https://news.wsu.edu/press-release/2018/07/30/yellow-butterfly-boom/
https://www.fox13seattle.com/news/butterfly-boom-why-washington-state-is-seeing-more-swallowtails-this-summer

Dragonflies (May-August peak)
https://british-dragonflies.org.uk/odonata/life-cycle-and-biology/

Mosquitoes (May-September, peak July-August)
https://allaboutants.net/when-is-mosquito-season-in-the-pacific-northwest/
https://www.opb.org/article/2023/06/20/pacific-northwest-weather-oregon-washington-mosquito-season/

Yellow Jackets (Peak August-September)
https://s3.wp.wsu.edu/uploads/sites/1384/2016/07/Yellowjackets-and-Paper-Wasps.pdf
https://foreststewardshipnotes.wordpress.com/2019/01/31/wasps-in-the-woods/

SALMON RUNS & FISH PHENOLOGY

Columbia River & Puget Sound Salmon Timing
https://fishingbooker.com/blog/salmon-fishing-in-washington/
https://fishingbooker.com/blog/puget-sound-fishing/
https://pugetsoundsportsfishing.com/understanding-salmon-runs-timing-your-fishing-trip/

Spring Chinook (March-May)
https://lancefisherfishing.com/columbia-river-spring-chinook-salmon-season-set/
https://wdfw.wa.gov/newsroom/news-release/2025-columbia-river-spring-chinook-seasons-announced
https://www.nwcouncil.org/history/SalmonAndSteelhead
https://wesportfish.com/our-sport-fishing/when-we-fish/spring/

Summer Chinook & Sockeye (June-August)
https://www.nwcouncil.org/history/SalmonAndSteelhead

Pink Salmon (Odd years, late July-August)
https://wdfw.wa.gov/newsroom/news-release/strong-return-columbia-river-coho-puget-sound-pink-salmon-projected

Coho (September-November)
https://fishingbooker.com/blog/salmon-fishing-in-washington/

Chum (October-December)
https://www.greaterseattleonthecheap.com/fall-salmon-spawning-season-in-western-washington/

Steelhead (Winter runs) - Information from WDFW sources

Herring Spawning (February-April peak)
https://medium.com/puget-sound-partnership/this-years-herring-spawn-events-in-puget-sound-were-the-largest-in-decades-855dce58df6f
https://wdfw.wa.gov/fishing/management/marine-beach-spawning
https://www.eopugetsound.org/articles/pacific-herring-distribution-puget-sound

MUSHROOM PHENOLOGY

Comprehensive Fruiting Calendar
https://salishmushrooms.com/fruiting-calendar/

Spring Mushrooms (Morels - March-July)
https://www.mushroom-appreciation.com/spring-mushroom-foraging-in-the-pacific-northwest.html

Chanterelles (Late summer-fall, September-November peak)
https://www.mushroom-appreciation.com/chanterelle-mushrooms.html
https://www.mushroom-appreciation.com/fall-mushroom-foraging-in-the-pacific-northwest.html
https://www.fs.usda.gov/pnw/pubs/pnw_gtr576.pdf
https://traveloregon.com/things-to-do/meet-the-oregon-state-mushroom/
https://www.seattletimes.com/life/outdoors/wa-may-see-its-worst-foraging-season-in-decades-what-to-know-if-you-do-go-mushroom-hunting/

Matsutake (August-November, October peak)
https://modern-forager.com/the-marvelous-and-mysterious-matsutake/

Cauliflower Mushrooms (September-November, October peak)
https://practicalselfreliance.com/cauliflower-mushroom/

King Boletes (Late summer-fall) - Information from fall mushroom foraging sources

Black Trumpets (November-March, winter prime)
https://unrulygardening.com/black-trumpet-mushrooms/
https://honest-food.net/of-trumpets-hedgehogs-and-yellowfeet/
https://www.mushroom-appreciation.com/winter-mushroom-foraging-pacific-northwest.html

Winter Mushrooms (Yellowfoot, Hedgehog, Oyster)
https://www.mushroom-appreciation.com/winter-mushroom-foraging-pacific-northwest.html

General PNW Mushroom Information
https://www.nwpb.org/2022/09/22/a-pacific-northwesterners-guide-to-mushroom-gathering/
https://myedmondsnews.com/2024/10/fungi-at-your-fingertips-new-book-showcases-pacific-northwests-mushroom-riches/

WILDLIFE PHENOLOGY

Harbor Seals (Geographic variation in pupping)
https://www.blubberblog.org/files/tag-pupping-season.html
https://www.eopugetsound.org/articles/harbor-seal
https://wdfw.wa.gov/sites/default/files/publications/00427/wdfw00427.pdf

Olympic Marmots (May emergence, September hibernation)
https://en.wikipedia.org/wiki/Olympic_marmot
https://interpretivecenter.org/olympic-marmot/

Elk Rutting Season (Late August-October, peak late September)
https://www.elk101.com/2023/01/which-week-to-hunt-elk-2023/
https://wonderingaroundoregon.wordpress.com/2016/10/02/a-chance-encounter-with-bugling-elk/

Gray Whale Migration
Northbound (March-June, peak early May)
Southbound (October-December, peak early January)
https://mmi.oregonstate.edu/wtg/research-projects/gray-whale/gray-whale-migration-study
https://www.researchgate.net/publication/237090523_Timing_of_the_gray_whale_southbound_migration

Brant Geese (November arrival) - Information from general bird migration sources

Varied Thrushes (Winter lowland return) - Information from winter bird sources

FALL FOLIAGE TIMING

Vine Maple (Late August-September by elevation)
https://www.deschuteslandtrust.org/news/blog/2021-blog-posts/it2019s-leaf-peeping-season-soak-in-fall-colors-with-the-glorious-vine-maple
http://nativeplantspnw.com/vine-maple-acer-circinatum/
https://www.wnps.org/blog/vine-maple-variations

Western & Subalpine Larch (Late September-early October)
https://explorenborgen.com/hikers-guide-to-see-larches-in-washington-when-where/
https://www.wta.org/news/magazine/features/the-science-of-larches
https://www.thegrahlife.com/blog/what-you-need-to-know-about-larch-hikes-in-washington
http://nativeplantspnw.com/western-larch-larix-occidentalis/

Bigleaf Maple & Other Deciduous Trees (October)
http://nativeplantspnw.com/big-leaf-maple-acer-macrophyllum/
https://wyeastblog.org/2016/05/31/meet-the-northwest-maples/

Pacific Dogwood (October-November)
http://natural-history-journal.blogspot.com/2018/11/pacific-dogwoods-one-last-dose-of-fall.html

Mountain Ash (Variable fall color)
https://wyeastblog.org/tag/mountain-ash/
https://nativeplantspnw.com/sitka-mountain-ash/

Black Cottonwood (October yellow)
https://owic.oregonstate.edu/black-cottonwood-populus-trichocarpa
https://en.wikipedia.org/wiki/Populus_trichocarpa

General Fall Foliage Timing
https://rove.me/to/oregon/fall-colors
https://rove.me/to/washington-wa/fall-colors
https://www.eugenecascadescoast.org/blog/post/oregon-fall-foliage/
https://www.koin.com/weather/autumn-foliage-outlook-released-when-will-portland-see-peak-foliage-07242025/
https://www.enviadventures.com/peak-fall-foliage-in-the-columbia-river-gorge-a-complete-guide/
https://www.almanac.com/fall-foliage-color-map-when-peak-foliage

WEATHER & CLIMATE PATTERNS

General Pacific Northwest Climate
https://wrcc.dri.edu/Climate/narrative_wa.php (Western Regional Climate Center)
https://seasonsyear.com/USA/Washington

Rainy Season Onset (October) - Documented in climate data from WRCC sources

Dry Season (Mid-June to July establishment) - Climate pattern documented in WRCC and general sources

June Gloom / Marine Layer
http://charlie.weathertogether.net/library/clouds/the-different-types-of-fog/
https://efiling.energy.ca.gov/GetDocument.aspx?tn=202685
https://en-academic.com/dic.nsf/enwiki/415548

Autumn Fog (September-November peak)
https://cliffmass.blogspot.com/2020/10/when-is-foggiest-time-of-year-in.html
http://karl.weathertogether.net/2021/10/10/why-is-autumn-so-foggy-in-the-pacific-northwest/

Winter Fog & Inversions (November-February)
https://ingallswx.com/2024/12/03/high-pressure-keeping-widespread-fog-and-low-clouds-in-pacific-northwest-lowlands/

Winter Solstice (December 21)
https://www.seattletimes.com/seattle-news/weather/welcome-to-the-shortest-day-of-the-year-seattle/
https://www.kgw.com/article/news/local/winter-solstice-longest-night-portland/283-3eb10ce0-eeac-4a30-8439-b406d2972d70
https://mynorthwest.com/pacific-northwest-weather/what-is-the-winter-solstice-and-why-does-it-matter/4021391
https://www.king5.com/article/news/local/sunsets-seattle-2024-winter/281-9f2414b9-3cf0-416f-9e86-73ad203e2803

Atmospheric Rivers & Pineapple Express - General knowledge from climate sources

Snowpack & Snow Water Equivalent
https://www.climatehubs.usda.gov/hubs/northwest/topic/snow-water-equivalent-swe-its-importance-northwest
https://www.aspectconsulting.com/blog/2022/2/7/snotel-part-1
https://www.drought.gov/news/snowpack-data-inform-decisions-across-pacific-northwest-2025-04-30

TRADITIONAL ECOLOGICAL KNOWLEDGE

Lushootseed Calendar & Coast Salish Seasonal Knowledge
https://tulaliplushootseed.com/time/
https://tulaliplushootseed.com/wp-content/uploads/2023/12/2024_Lushootseed_Calendar-FINAL3-Reduced-Size.pdf
https://tulaliplushootseed.com/wp-content/uploads/2022/12/2023_Lushootseed_Calendar-Final-Reduced-Size.pdf
https://tulalipnews.com/tag/tulalip-lushootseed-language-department/

Indigenous Phenology Research
https://www.researchgate.net/publication/267407639_Traditional_phenological_knowledge_of_Aboriginal_Peoples_in_British_Columbia
https://ecologicalprocesses.springeropen.com/articles/10.1186/s13717-018-0136-6
https://www.researchgate.net/publication/371398018_Traditional_ecological_knowledge-based_calendar_system_for_sustainable_seasonal_grazing_in_the_Pamir_Mountains

USDA FOREST SERVICE RESEARCH

Pacific Northwest Research Station

Phenology of Pacific Northwest Tree Species (Harrington, Ford, St. Clair 2016)
https://www.fs.usda.gov/research/treesearch/53128
https://www.fs.usda.gov/pnw/pubs/pnw_gtr576.pdf
PhenoMap - Real-time Land Surface Phenology Monitoring
https://www.fs.usda.gov/pnw/publications/monitoring-land-surface-phenology-near-real-time-using-phenomap

General USFS Wildflower Resources
https://www.fs.usda.gov/wildflowers/ (various plant-of-the-week features)

ARBORETUMS & BOTANICAL GARDENS

Washington Park Arboretum (Seattle) - 230 acres with phenology records
https://botanicgardens.uw.edu/washington-park-arboretum/
https://arboretumfoundation.org/visit/tour-the-grounds/

Hoyt Arboretum (Portland) - Community science phenology programs
https://www.hoytarboretum.org/support/volunteer/community-science/
https://www.hoytarboretum.org/support/volunteer/

NATIVE PLANT SOCIETIES

Washington Native Plant Society - 2,750+ members, extensive phenology observations
https://www.wnps.org/
https://wnpskoma.org/meetings/
https://www.cbwnps.org/ (Columbia Basin Chapter)
https://www.wagives.org/organization/Washington-Native-Plant-Society

Native Plant Society of Oregon - Contributing to statewide phenology data (Various chapter resources)

ADDITIONAL SPECIALIZED SOURCES

Mayfly & Aquatic Insect Hatches
https://topflyguides.com/washington-rivers-fish/yakima-river-hatches/
https://pacificflyfishers.com/blogs/pff/where-to-go-fly-fishing-in-washington-in-the-month-of-may

Bird Migration
https://www.audubon.org/news/its-summer-and-means-fall-migration-already-underway

Climate Change Impacts on Phenology
https://cig.uw.edu/wp-content/uploads/sites/2/2020/12/wacciach2rcm643.pdf
Various USDA Climate Hub resources

National Park Service Phenology Studies
https://www.nps.gov/articles/parkscience33-1_17-26_wilson_et_al_3850.htm