What to look for in nature in New Jersey this May

What happens on the Delaware Bay beaches in May, and why does it matter to red knots?

• Horseshoe crabs spawn every May

  Evenings in May and early June, with the best watching around the new and full moons · Bay beaches in Cape May and Cumberland counties

  Delaware Audubon calls Delaware Bay the largest horseshoe crab spawning area in the world and says the crabs come ashore every May, with the best viewing in the evening at high tide near the month's new and full moons. In 2027 those moons fall on May 6 and May 20 (see the moon table below). Treat that as a rule of thumb, not a schedule: the Conserve Wildlife Foundation of New Jersey reports that unusually cold bay water in the spring of 2020 pushed the spawn back to early June, and the following year's spawn arrived on time with plenty of eggs.

• A stopover that decides the summer

  Mid to late May, for about two weeks per bird · The bay shore, with the heaviest feeding at the water's edge

  The U.S. Fish and Wildlife Service describes Delaware Bay as the principal spring staging area for an estimated 50 to 80 percent of the rufa red knot population, the final Atlantic coast stop before the Arctic. Some of these knots fly more than 9,300 miles north each spring. The agency says the eggs are so abundant and easy to digest that a bird can nearly double its weight in about two weeks. Delaware Audubon adds that knots arrive at very low weights, lower than at any other stopover. The National Audubon field guide ties the species' decline in part to overharvest of horseshoe crabs along the central Atlantic coast, which cut the supply of eggs.

• Two very different springs in the count

  Counts made in May, reported afterward · Delaware Bay, New Jersey and Delaware shores

  Dr. Larry Niles of the Conserve Wildlife Foundation reported about 34,500 red knots in the bay in 2018, the highest count in at least 15 years by his account, noting that part of the rise came from birds staying longer rather than a larger population. In 2021 the foundation's biologists counted 6,880, the lowest since counts began in 1982, compared with almost 100,000 passing through in the early 1980s. The foundation traced that drop mostly to the 2020 season: knots reached the bay in May, found few eggs because of the late spawn, and moved on underweight. The survey method catches only part of the birds present, so these are yearly snapshots, not exact totals.

• Beaches that are closed on purpose

  May, with stewards on site · Nine restricted beaches in Cape May and Cumberland counties

  The foundation says nine beaches in the two counties have restricted access during May so shorebirds can feed undisturbed. Stewards work them in all weather and in biting-insect season, explaining to visitors why the fences and signs matter. A flushed flock burns energy it cannot spare. If you want to watch, stay outside the posted areas, keep a long distance, and use binoculars. The Cape May Bird Observatory distributes bayshore birding maps, and its Northwood Center in Cape May Point is the place to ask where public viewing is open that week.

Which birds pass Cape May Point in May, and what makes a big day?

• Wind runs the show

  Throughout May · Cape May Point and Higbee Beach

  The 2022 observers wrote that persistent easterly winds produced poor landbird movement through the first half of the month, and that a shift to the north on May 5 immediately brought more songbirds. The strongest landbird days they describe came on a northerly shift, on the calm, sunny May 16, and on May 23, when a cold front brought northwest winds. The authors single out northeast winds, like those of May 24 to 26 that year, as the ones they do not favor.

• Seabirds when the weather turns bad

  A storm or fog bank, any day · The beach and the point's ocean side

  The same easterlies that hurt songbird counts push seabirds close to shore. In the 2022 summaries a strong coastal storm on May 7 and rain on May 8 produced Caspian terns, a Manx shearwater and a Wilson's storm-petrel, and fog on May 10 brought a spring-record 13 roseate terns. Late in the month the count logged 28 sooty shearwaters on May 25 and 14 Wilson's storm-petrels on May 26.

Where can I find migrating warblers inland, and when do hummingbirds arrive?

• Great Swamp National Wildlife Refuge, Morris County

  The first two weeks of May · The Wildlife Observation Center and the boardwalks

  The Friends of Great Swamp describe early May as the peak of spring songbird migration, with woods full of color and sound: thrushes calling, vireos, bright migrating warblers, and ruby-throated hummingbirds appearing. The refuge reports more than 244 bird species. Roughly a mile and a half of boardwalk and short trail, with blinds, starts at the Wildlife Observation Center off Long Hill Road, and 8.5 miles of wilderness trail are for walkers only, so waterproof boots help. The visitor center has posted Tuesday and Thursday through Sunday hours, but confirm before a long drive.

• Flowers at the swamp's edge

  First half of May · Wet meadows and shaded borders

  The same Friends of Great Swamp page says the spring ephemerals are giving way to summer wildflowers, with golden ragwort, pinxter azalea, blue flag iris and floating yellow spatterdock expected in bloom. Photograph without picking, and stay on the marked trail, because wet ground tears up quickly.

• Delaware Water Gap National Recreation Area

  May, with the most warblers in the first half of the month · River corridor and ridge forests in Sussex and Warren counties

  The National Park Service says over 30 warbler species have been recorded in spring migration along the river valley, including cerulean, blackburnian and black-throated green, and that the area has more than 260 bird species in all. Other nesting birds on its list include Louisiana waterthrush, scarlet tanager and wild turkey. Bald eagles now nest here; the first successful nest fledged two young in 2002. The river itself runs about 40 miles through the park, and the agency's advice is to wear a fitted lifejacket and have a plan.

• Ruby-throated hummingbirds

  Arriving in the first half of May in the north · Gardens, feeders and swamp edges

  The Great Swamp page lists hummingbirds among early-May arrivals. Journey North keeps an ongoing map of the species' progress north and takes sightings from anyone through its report page, so a first-of-year log entry is a real contribution. Write down the date and place you see your first one, then compare with a neighbor's.

Where do beach birds and terrapins nest, and how do I give them room?

• Three endangered beach nesters

  Nesting runs from spring into summer · Barrier islands and open beaches along the Atlantic shore

  The state's brochure says piping plovers, least terns and black skimmers nest on the open sand and sometimes in the dunes, and that the plover is also federally threatened. Biologists fence nesting areas and sign them, sometimes caging individual plover nests to keep predators off. The brochure warns that camouflaged eggs and chicks are easy to step on, that parents leaving a nest expose eggs to heat and predators, and that chicks can die within minutes on a hot day. It also says dogs are not allowed on most beaches during nesting season, cats should stay indoors, and food scraps should not be left on the sand because they attract gulls, crows and foxes.

• A refuge beach that stays closed

  April 1 through August 31 · Holgate unit, Edwin B. Forsythe National Wildlife Refuge

  The refuge keeps its Holgate unit shut to visitors from the first of April until the end of August so that beach birds can nest in peace. Elsewhere on the refuge, the eight-mile Wildlife Drive, with two observation towers and a salt marsh boardwalk, is open daily from sunrise to sunset for an entry fee. The refuge says sea lavender blooms in its high marsh, though it gives no month.

• Diamondback terrapins on the road

  Peak nesting, with the foundation giving no exact dates · Great Bay Boulevard in Little Egg Harbor, and coastal roads in southern Ocean and Atlantic counties

  The Conserve Wildlife Foundation's terrapin project says about 50 terrapins were killed or injured each year on Great Bay Boulevard, a five-mile road through a wildlife management area, before the project began in 2010, and that the number has reportedly been cut in half. Volunteers patrol during peak nesting. The Wetlands Institute in Stone Harbor reported on July 15, 2011 as that year's nesting season ended, counting 1,065 rescued eggs, 482 roadkills and over 275 terrapins helped across roads, so the season runs into early summer. The foundation's page names no start date, so ask either organization when their first crossings appear.

• What to do if you meet a terrapin

  Any time on a coastal road · Roads that cross saltmarsh

  The foundation's advice: slow down near marsh roads, pull over safely with hazard lights on, and move the turtle to the soft shoulder facing the direction it was headed. Do not carry it far, since terrapins have small home ranges. Log sightings on the project's iNaturalist page. The species is protected by state law, and suspected collecting goes to the 24-hour hotline, 877-WARN-DEP. Crabbers should use bycatch reduction devices on their traps.

What nests in New Jersey's fields in May, and what about fawns, bears and bats?

• Bobolinks and grasshopper sparrows

  Nesting from May on · Hayfields and grasslands, including Joint Base McGuire-Dix-Lakehurst

  The Conserve Wildlife Foundation lists the bobolink and grasshopper sparrow as state-threatened and says the joint base hosts the state's second-largest known breeding colony of grasshopper sparrows. About a third of the state's threatened and endangered birds depend on grassland. The foundation says mowing, burning and grazing should happen before or after nesting, but earlier and more frequent hay harvests now often fall during the critical weeks. If you farm or manage a hayfield, ask the foundation about timing.

• Summer Bat Count window opens

  Two counts between May 15 and June 21 · Attics, barns, churches and bat houses with a known roost

  New Jersey has nine bat species, six year-round residents and three migratory, and five are state endangered. The foundation's volunteers count bats leaving summer roosts at dusk, with two surveys between May 15 and June 21 and two more between July 6 and July 31, skipping nights with rain, wind over about 15 mph or temperatures below 55 degrees. White-nose syndrome, first confirmed in the state in January 2009, has cut populations of affected species at the most important hibernation sites by almost 98 percent.

• Fawns are not abandoned

  Spring and early summer · Lawns, woodland edges and brush

  The state's Division of Fish and Wildlife fawn page gives a single instruction for a fawn you find alone: leave it alone. A doe leaves her young hidden for long stretches and returns. Keep dogs away and do not touch.

• Black bears and their yearlings

  Active in all 21 counties · Northwestern forests and anywhere people live near woods

  The New Jersey Conservation Foundation says bears emerge from winter dens during March and April and by now roam all 21 counties. Females give birth in mid-January and average three cubs, so by May the cubs are about four months old, and a cub does not strike out until it is about a year and a half old. Feeding bears is illegal in the state. Bear-resistant trash cans, indoor pet feeding and food locked in the car while camping all help.

When is the last freeze in New Jersey, and can May still be cold?

• Late cold snaps, recent examples

  May 13 to 18, 2021 and 2023 · Walpack in Sussex County and Berkeley Township

  The state climatologist's office recorded 28 degrees at Walpack on May 13, 2021, with the last freezing reading at a state weather-network station falling on May 16 at Berkeley Township. In 2023 Walpack dropped to 25 on May 18, though the office reported no significant vegetation damage. In May 2022 the coldest morning came on May 1, with 26 at Walpack and 27 at Berkeley Township. Late freezes are rare in the south and coast but can still catch tender plants inland, so wait until mid-May to move seedlings out in the north.

How much daylight does New Jersey gain in May?

What is May weather like in New Jersey, and what are the hazards?

• Four Mays, four moods

  May 2021, 2022, 2023 and 2024 · Statewide

  May 2021 averaged 61.0 degrees, 0.2 below normal, with a waterspout over Barnegat Bay on May 8 and a statewide dry classification by May 27. May 2022 averaged 63.3, tying as the 14th mildest on record since 1895, then ended with a record 98 degrees at Newark Airport on May 31 and a first-of-the-season EF0 tornado in Monmouth County on May 20. May 2023 averaged 59.3, 1.9 below normal, and May 2 to 31 was the second driest such stretch on record at about one inch statewide. May 2024 averaged 63.9, with nights that were the fourth warmest on record, and squalls on May 23 sent a 59 mph gust through Cream Ridge and downed trees across the northern half of the state.

• Wildfire smoke and woods fires

  May 2021 and May 2023 · Pine Barrens state forests

  The state climatologist's office reports wildfires of about 600 acres at Bass River State Forest and over 400 at Brendan Byrne State Forest on May 16 to 18, 2021. In 2023 a fire at Bass River began on May 31 at several hundred acres and passed 3,000 acres by the next morning, and smoke from Canadian wildfires hazed the sky over most of the state between May 9 and May 24. The state's forest fire chief, quoted by the Philadelphia Inquirer in April 2026, put the usual peak at mid-March through mid-May; a typical year has about 1,100 fires, against 1,322 fires and 27,230 acres burned in 2025.

• Tornadoes and thunderstorms

  Any month, with spring storms common · Statewide

  The state climatologist's tornado page puts the state's average near two a year and calls most of them weak. The May 17, 2022 storms brought hail to Mercer County and the May 20 storms dropped hail up to 2.5 inches in Shamong, a good reminder that a spring afternoon can turn quickly.

What can you see in the New Jersey sky in May 2027?

• Eta Aquariid meteors, an excellent year

  Best on the mornings of May 5, 6 and 7, in the last hours before dawn · Face southeast and look wide

  Sea and Sky rates the Eta Aquariids an above-average shower and says the Moon is nearly absent as it peaks over the night of May 6 to 7. A razor-thin crescent follows the new moon at 6:58 a.m. on May 6. The constellation Aquarius climbs the southeastern sky only a short while before first light at our latitude, so New Jersey sees fewer streaks than places farther south. Sea and Sky puts the best Northern Hemisphere rate near 30 an hour, and a fair expectation here is fewer. Dark adaptation takes a good twenty minutes, so skip the phone screen.

• Venus and Saturn, close but low

  Mornings of May 6, 7 and 8 · Low in the east before sunrise

  By our calculation the pair ride about a degree apart on the mornings of the 6th and 8th and only 0.6 degrees apart on the 7th. Both hug the eastern horizon in Pisces. Venus, near magnitude minus 3.9, lifts only an hour ahead of the Sun, and fainter Saturn, about 0.7, sits beside it. Binoculars and an unobstructed horizon will help.

• Flower Moon and seasonal Blue Moon

  Full at 6:59 a.m. on Thursday, May 20; best viewing the evening of Wednesday, May 19 · Low in the east after sunset

  The Moon turns full in the early morning, so the round disk to watch for climbs into view the evening before. By our calculation moonrise near New York is about 7:52 p.m. on the 19th. Sea and Sky gives both names. It also counts this one a Blue Moon by the seasonal reckoning, in which a season holding four full moons names the third; this spring's four run from March to mid June. The modern calendar-month rule gives 2027 no Blue Moon.

• Jupiter, Mars and the Moon

  Evenings of May 12 and 13 · The southwest after dark

  By our calculation the Moon, a bit shy of first quarter, passes 1.2 degrees from Jupiter on May 12, nearest at 5:52 p.m. in broad daylight, so look again as dusk deepens. The next night Mars is roughly three degrees from the Moon. Jupiter shines high and stays up late; on May 1 it sets about seven hours after the Sun.

• Mercury at its widest

  Look 45 to 90 minutes after sunset from about May 12 to June 5; greatest elongation May 28 · Low in the west-northwest

  By our calculation Mercury sets just 18 minutes after the Sun on May 1, then a far more comfortable 97 minutes after on May 15, at about magnitude minus 0.6. Sea and Sky lists the widest separation, 22.9 degrees east of the Sun, for May 28; our figure puts that moment at 9:14 a.m., so both evenings, the 27th and the 28th, work equally well. Scan the west-northwest horizon between about May 12 and June 5, ideally from a shore with an open view.

• Milky Way after midnight

  May 1 to 14 and May 25 to 31 · A dark site such as the Pine Barrens or Sussex County

  By our calculation, near 40 degrees north the galaxy's bright center stands in full darkness, with no Moon, for up to about 3.8 hours on the best of those nights. The Moon spoils the stretch from May 15 to 24.

What are good May nature outings for New Jersey families?

Safety notes for May in New Jersey