Spring at William O'Brien State Park, Minnesota

Month by month

Marine on St. Croix in May

Warbler waves, wildflower carpets and the woods going green almost overnight.

Photo: Tony Webster from Minneapolis, Minnesota, United States / CC BY-SA 2.0, via Wikimedia Commons

67°Faverage high
49°Faverage low
4.28 inprecipitation12 wet days
1hot daysreaching 85°F or more
14.9 hdaylightsunrise 5:42 AM · sunset 8:32 PM

What May is like

May is the most exciting month for naturalists. Migrating warblers, orioles and grosbeaks pour through the river corridor, and more bird species are recorded around Marine now than at any other time of year. Wild geranium, columbine and Jack-in-the-pulpit bloom in the woods. The river is still higher and colder than in summer, but by late May the first paddlers are back.

In May, Marine on St. Croix averages a high of 67°F and a low of 49°F. Expect about 4.3 in of rain spread over roughly 12 wet days. Days last about 14.9 hours, with roughly 10.3 hours of sunshine.

The river in May

Long-term average flow at St. Croix Falls in May is 7,712 cfs — 1.7× the yearly average, the season of fast, cold, high water. Paddle only with experience and a wetsuit or drysuit, and check the river dashboard first.

Best things to do in May

Based on climate normals and when wildlife is most often recorded, May is a good month for: hiking, wildflowers, birding.

  • Bird the floodplain forest at sunrise during peak migration.
  • Walk the woodland trails for spring wildflowers.
  • Join the village’s Memorial Day program at Oakland Cemetery.

What to pack

  • light layers for cool mornings
  • rain jacket
  • insect repellent (ticks and mosquitoes are common in woods and wetlands)
  • a dry bag if you plan to paddle

Events in May

Wildlife to look for in May

Species with a large share of their local iNaturalist records in May. The strip shows each species' records across the year.

Birds

Northern Yellow Warbler

Northern Yellow Warbler

Setophaga aestiva

30 local records · peak May

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(c) Ad Konings, some rights reserved (CC BY-NC), uploaded by Ad Konings

Baltimore Oriole

Baltimore Oriole

Icterus galbula

52 local records · peak May

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(c) Tom Murray, some rights reserved (CC BY-NC)

Rose-breasted Grosbeak

Rose-breasted Grosbeak

Pheucticus ludovicianus

94 local records · peak May

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(c) Norma Maurice, some rights reserved (CC BY-NC-ND), uploaded by Norma Maurice

Swainson's Thrush

Swainson's Thrush

Catharus ustulatus

11 local records · peak May

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(c) Jing-Yi Lu, some rights reserved (CC BY-NC), uploaded by Jing-Yi Lu

Plants & wildflowers

blue phlox

Blue phlox

Phlox divaricata

53 local records · peak May

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(c) Noel Pennington, some rights reserved (CC BY-NC), uploaded by Noel Pennington

wood anemone

Wood anemone

Anemonoides quinquefolia

83 local records · peak May

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(c) laurenis4animals, some rights reserved (CC BY-NC), uploaded by laurenis4animals

rue anemone

Rue anemone

Thalictrum thalictroides

152 local records · peak May

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(c) Rene Kimray, some rights reserved (CC BY-NC), uploaded by Rene Kimray

wild geranium

Wild geranium

Geranium maculatum

95 local records · peak May

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(c) Mark Kluge, some rights reserved (CC BY-NC), uploaded by Mark Kluge

Mushrooms & fungi

American yellow morel

American yellow morel

Morchella americana

4 local records · peak May

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(c) noah_siegel, some rights reserved (CC BY-NC-SA), uploaded by noah_siegel

Dryad's Saddle

Dryad's Saddle

Cerioporus squamosus

37 local records · peak May

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(c) Sarah DeLong-Duhon, some rights reserved (CC BY-NC-SA), uploaded by Sarah DeLong-Duhon

Half-free Morel

Half-free Morel

Morchella punctipes

2 local records · peak May

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(c) Ansel Oommen, some rights reserved (CC BY-NC), uploaded by Ansel Oommen

aspen oyster mushroom

Aspen oyster mushroom

Pleurotus populinus

3 local records · peak May

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(c) Anna, some rights reserved (CC BY-NC), uploaded by Anna

Insects & butterflies

Eastern Pine Elfin

Eastern Pine Elfin

Callophrys niphon

5 local records · peak May

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(c) Jason M Crockwell, some rights reserved (CC BY-NC-ND), uploaded by Jason M Crockwell

Bumble Flower Beetle

Bumble Flower Beetle

Euphoria inda

4 local records · peak May

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(c) Jason King, some rights reserved (CC BY-NC), uploaded by Jason King

Six-spotted Tiger Beetle

Six-spotted Tiger Beetle

Cicindela sexguttata

13 local records · peak May

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(c) soulflower_ecological, some rights reserved (CC BY-NC)

Springtime Darner

Springtime Darner

Basiaeschna janata

5 local records · peak May

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(c) Seabrooke Leckie, some rights reserved (CC BY-NC-ND)

Mammals

Eastern Chipmunk

Eastern Chipmunk

Tamias striatus

25 local records · peak May

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(c) Mike Leveille, some rights reserved (CC BY-NC), uploaded by Mike Leveille

Southern Flying Squirrel

Southern Flying Squirrel

Glaucomys volans

3 local records · peak May

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(c) Todd Belanger, some rights reserved (CC BY-NC), uploaded by Todd Belanger

White-tailed Deer

White-tailed Deer

Odocoileus virginianus

256 local records · peak July

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(c) jefferykarafa, some rights reserved (CC BY-NC), uploaded by jefferykarafa

Eastern Fox Squirrel

Eastern Fox Squirrel

Sciurus niger

5 local records · peak May

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(c) Tobin Brown, some rights reserved (CC BY-NC), uploaded by Tobin Brown

Reptiles & amphibians

Western Foxsnake

Western Foxsnake

Pantherophis ramspotti

18 local records · peak May

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(c) John Sullivan, some rights reserved (CC BY-NC), uploaded by John Sullivan

Painted Turtle

Painted Turtle

Chrysemys picta

72 local records · peak June

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(c) Susan Elliott, some rights reserved (CC BY-NC), uploaded by Susan Elliott

Gray Treefrog

Gray Treefrog

Dryophytes versicolor

19 local records · peak May

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(c) Todd Pierson, some rights reserved (CC BY-NC-SA)

Eastern Foxsnake

Eastern Foxsnake

Pantherophis vulpinus

3 local records · peak May

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(c) Diana-Terry Hibbitts, some rights reserved (CC BY-NC), uploaded by Diana-Terry Hibbitts