Year calendar · 78 places

Maywhat's in season

What's in season in May?

May is wildflowers and synchronous fireflies season at the places we track. Wildflowers is in its usual window at 29 places, the most in the week of May 15–21 (28), from Point Reyes (Feb 1–Aug 31) to Rocky Mountain (May 21–Aug 10). Synchronous fireflies: Congaree National Park (May 11–Jun 20) and Great Smoky Mountains (May 21–Jun 10). Starting this month: azaleas at Shenandoah and azaleas and rhododendrons at Blue Ridge Parkway, North Carolina.

Updated Sep 28. Sources: National Park Service, Shenandoah FAQ ↗ (opens in a new tab), National Park Service, Blue Ridge Parkway FAQ ↗ (opens in a new tab)

Peaking in May

Each place's usual window, from its own sources

Wildflowers

29 places in May · 6 start this month

25May 1–7

26May 8–14

28May 15–21

23May 22–31

California

Point ReyesLocal timing: Feb 1–Aug 31
Lava BedsLocal timing: Mar 1–Sep 30
PinnaclesMar 1–May 31
YosemiteLocal timing: Mar 1–Aug 31
WhiskeytownLocal timing: Apr 1–Aug 31
Lassen VolcanicLocal timing: May 21–Sep 30

Washington

North CascadesLocal timing: Feb 21–Sep 10
Hanford ReachLocal timing: Apr 1–May 15
Turnbull RefugeMay 11–May 20

Kentucky

Mammoth CaveLocal timing: Mar 1–May 31

Mississippi

Natchez Trace Parkway, MississippiLocal timing: Mar 1–May 31

North Carolina

Nantahala National ForestLocal timing: Mar 15–May 15
Pisgah National ForestLocal timing: Mar 21–May 15
Blue Ridge ParkwayApr 21–May 10

Tennessee

Cherokee National ForestLocal timing: Mar 21–May 31

Ohio

Cuyahoga ValleyLocal timing: Mar 21–May 15

Virginia

George Washington and JeffersonLocal timing: Mar 21–May 31
ShenandoahLocal timing: Mar 21–Jun 30

Delaware

Bombay HookLocal timing: Apr 1–May 31

Maryland

Catoctin MountainLocal timing: Apr 1–May 31

Idaho

Deer Flat RefugeLocal timing: Apr 1–May 31

Oregon

John Day Fossil BedsLocal timing: Apr 1–Jul 31

North Dakota

Long Lake RefugeLocal timing: Apr 1–Aug 31

Wyoming

YellowstoneLocal timing: Apr 1–Jul 31
Grand TetonLocal timing: May 1–Sep 30

Michigan

Pictured RocksLocal timing: Apr 15–Jun 10

South Dakota

Spearfish CanyonLocal timing: May 1–Jul 10

District of Columbia

Kenilworth Aquatic GardensLocal timing: May 21–Sep 30

Colorado

Rocky MountainLocal timing: May 21–Aug 10

Synchronous fireflies

2 places in May · 2 start this month

0May 1–7

1May 8–14

2May 15–21

2May 22–31

South Carolina

Congaree National ParkMay 11–Jun 20

Tennessee

Great Smoky MountainsMay 21–Jun 10

Also in May

From our places' year strips, each with its source

Blooms, blossoms and green-up

Starting in May

Azaleas Shenandoah · May–Jun
Azaleas and rhododendrons Blue Ridge Parkway, North Carolina · May–Jun
Green-up Jay Peak, Vermont · May–Jun
Mid-spring wildflowers (Tennessee section) Natchez Trace Parkway, Tennessee · May–Jun
Spring wildflowers Escudilla Mountain · May
Spring wildflowers, Lost Lake trails Chequamegon-Nicolet · May
Summer flowers Kenilworth Aquatic Gardens · May–Sep
Tundra wildflowers Rocky Mountain · May–Aug

And 5 more.

Still going at 42 places: wildflowers (9 places), spring wildflowers (9 places), green-up (2 places).

Festivals and night skies

Starting in May

International Migratory Bird Day (third Saturday in May) Missisquoi Refuge · May
Memorial Day commemoration Antietam · May
Ranger astronomy programs Great Basin · May–Sep
Synchronous fireflies Great Smoky Mountains, Tennessee · May–Jun
Synchronous fireflies (about two weeks) Congaree National Park, South Carolina · May–Jun
Tulip Festival Albany, New York · May
Tulip Time Festival Holland, Michigan · May
Wildflower Weekend Shenandoah · May

Still going at 1 place: wildflower tours.

Snow and winter

Still going at 8 places: deep snow, tire chains required, snow in the high country.

Out and about

Starting in May

Backbone Horse Campground open Finger Lakes National Forest, New York · May–Nov
Backcountry roads open Valles Caldera · May–Nov
Bagley Rapids, Boulder Lake and Ada Lake campgrounds open Lakewood · May–Oct
Baker Lake campground open Superior National Forest, Minnesota · May–Sep
Bandy Creek pool (weekends) Big South Fork · May–Sep
Bark Camp campground open George Washington and Jefferson · May–Sep
Barnes Field group sites by reservation Pinkham Notch, New Hampshire · May–Oct
Bay Furnace campground open Hiawatha National Forest, Michigan · May–Oct

And 57 more.

Still going at 44 places: busy season (2 places), songbird and warbler migration (2 places), cadillac summit road open.

Know before you go

Starting in May

Elkmont closed after noon on firefly nights (reservations and campers only) Great Smoky Mountains, Tennessee · May–Jun
Hottest months Big Bend · May–Aug
Visitor center, boardwalk and front-country trails close at 4:30 p.m. on firefly nights Congaree National Park, South Carolina · May
Warbler nesting areas closed Au Sable River · May–Jul

Still going at 12 places: boulder canyon raptor nesting closures, timon and rod & gun campgrounds closed, painted rock closed.

Sources (12)

Questions people ask

Where are wildflowers in May?

At the places we track: Point Reyes, California (local timing Feb 1–Aug 31); North Cascades, Washington (local timing Feb 21–Sep 10); Lava Beds, California (local timing Mar 1–Sep 30); Mammoth Cave, Kentucky (local timing Mar 1–May 31); Natchez Trace Parkway, Mississippi, Mississippi (local timing Mar 1–May 31); Pinnacles, California (usually Mar 1–May 31); and 23 more on this page.

Where are synchronous fireflies in May?

At the places we track: Congaree National Park, South Carolina (usually May 11–Jun 20); Great Smoky Mountains, Tennessee (usually May 21–Jun 10).

What festivals are in May?

International Migratory Bird Day (third Saturday in May) at Missisquoi Refuge (May); Memorial Day commemoration at Antietam (May); Ranger astronomy programs at Great Basin (May–Sep); Synchronous fireflies at Great Smoky Mountains, Tennessee (May–Jun); Synchronous fireflies (about two weeks) at Congaree National Park, South Carolina (May–Jun); Tulip Festival at Albany, New York (May); Tulip Time Festival at Holland, Michigan (May); Wildflower Weekend at Shenandoah (May). Dates change each year; each place page links its source.

What should I know before a trip in May?

Great Smoky Mountains, Tennessee: elkmont closed after noon on firefly nights (reservations and campers only); Big Bend: hottest months; Congaree National Park, South Carolina: visitor center, boardwalk and front-country trails close at 4:30 p.m. on firefly nights; Au Sable River: warbler nesting areas closed.