56 butterflies were recorded flying in New Jersey in October in our iNaturalist sample; 2 of the top 50 are at their peak this month. The list is ranked by number of research-grade observations.
Top butterflies in October

Monarch

Common Buckeye
Huron Skipper

Small White

American Lady

Red Admiral

Orange Sulphur

Painted Lady

Variegated Fritillary

Black Swallowtail

Fiery Skipper

Pearl Crescent
All butterflies flying in New Jersey in October
| # | Species | Scientific name | Family | Obs. | Peak in state |
|---|---|---|---|---|---|
| 1 | Monarch | Danaus plexippus | Brush-footed Butterflies | 1,224 | Aug (past peak) |
| 2 | Common Buckeye | Junonia coenia | Brush-footed Butterflies | 724 | Sep (past peak) |
| 3 | Huron Skipper | Atalopedes huron | Skippers | 288 | Sep (past peak) |
| 4 | Small White | Pieris rapae | Whites, Yellows, and Sulphurs | 216 | Jul (past peak) |
| 5 | American Lady | Vanessa virginiensis | Brush-footed Butterflies | 193 | May (past peak) |
| 6 | Red Admiral | Vanessa atalanta | Brush-footed Butterflies | 163 | Jul (past peak) |
| 7 | Orange Sulphur | Colias eurytheme | Whites, Yellows, and Sulphurs | 146 | Sep (past peak) |
| 8 | Painted Lady | Vanessa cardui | Brush-footed Butterflies | 136 | Sep (past peak) |
| 9 | Variegated Fritillary | Euptoieta claudia | Brush-footed Butterflies | 131 | Aug (past peak) |
| 10 | Black Swallowtail | Papilio polyxenes | Swallowtails and Parnassians | 126 | Aug (past peak) |
| 11 | Fiery Skipper | Hylephila phyleus | Skippers | 118 | Sep (past peak) |
| 12 | Pearl Crescent | Phyciodes tharos | Brush-footed Butterflies | 99 | Jul (past peak) |
| 13 | Ocola Skipper | Panoquina ocola | Skippers | 88 | Sep (past peak) |
| 14 | Eastern Tailed-Blue | Everes comyntas | Gossamer-winged Butterflies | 85 | Sep (past peak) |
| 15 | Long-tailed Skipper | Urbanus proteus | Skippers | 83 | Sep (past peak) |
| 16 | Red-banded Hairstreak | Calycopis cecrops | Gossamer-winged Butterflies | 78 | Aug (past peak) |
| 17 | Eastern Comma | Polygonia comma | Brush-footed Butterflies | 77 | Aug (past peak) |
| 18 | Common Checkered-Skipper | Burnsius communis | Skippers | 76 | Oct (peak) |
| 19 | Question Mark | Polygonia interrogationis | Brush-footed Butterflies | 68 | Aug (past peak) |
| 20 | Gray Hairstreak | Strymon melinus | Gossamer-winged Butterflies | 67 | Sep (past peak) |
| 21 | Cloudless Sulphur | Phoebis sennae | Whites, Yellows, and Sulphurs | 64 | Sep (past peak) |
| 22 | Viceroy | Limenitis archippus | Brush-footed Butterflies | 44 | Sep (past peak) |
| 23 | Mourning Cloak | Nymphalis antiopa | Brush-footed Butterflies | 42 | Mar (past peak) |
| 24 | American Copper | Lycaena hypophlaeas | Gossamer-winged Butterflies | 35 | Jul (past peak) |
| 25 | Silver-spotted Skipper | Epargyreus clarus | Skippers | 29 | Aug (past peak) |
| 26 | Spicebush Swallowtail | Papilio troilus | Swallowtails and Parnassians | 25 | Aug (past peak) |
| 27 | Clouded Sulphur | Colias philodice | Whites, Yellows, and Sulphurs | 25 | Sep (past peak) |
| 28 | Sleepy Orange | Eurema nicippe | Whites, Yellows, and Sulphurs | 25 | Jul (past peak) |
| 29 | Eastern Tiger Swallowtail | Papilio glaucus | Swallowtails and Parnassians | 22 | Jul (past peak) |
| 30 | White M Hairstreak | Parrhasius m-album | Gossamer-winged Butterflies | 22 | Sep (past peak) |
| 31 | Peck's Skipper | Polites peckius | Skippers | 22 | Jul (past peak) |
| 32 | Horace's Duskywing | Erynnis horatius | Skippers | 21 | Jul (past peak) |
| 33 | Red-spotted Admiral | Limenitis arthemis | Brush-footed Butterflies | 17 | Aug (past peak) |
| 34 | Brazilian Skipper | Calpodes ethlius | Skippers | 13 | Sep (past peak) |
| 35 | American Snout | Libytheana carinenta | Brush-footed Butterflies | 12 | Jul (past peak) |
| 36 | Salt Marsh Skipper | Panoquina panoquin | Skippers | 10 | Jul (past peak) |
| 37 | Pipevine Swallowtail | Battus philenor | Swallowtails and Parnassians | 9 | Jul (past peak) |
| 38 | Least Skipper | Ancyloxypha numitor | Skippers | 8 | Aug (past peak) |
| 39 | Great Spangled Fritillary | Argynnis cybele | Brush-footed Butterflies | 8 | Jun (past peak) |
| 40 | Summer Azure | Celastrina neglecta | Gossamer-winged Butterflies | 6 | Jun (past peak) |
| 41 | Wild Indigo Duskywing | Erynnis baptisiae | Skippers | 4 | Aug (past peak) |
| 42 | Gulf Fritillary | Dione vanillae | Brush-footed Butterflies | 3 | Oct (peak) |
| 43 | Dun Skipper | Euphyes vestris | Skippers | 3 | Jul (past peak) |
| 44 | Checkered White | Pontia protodice | Whites, Yellows, and Sulphurs | 3 | Sep (past peak) |
| 45 | Harvester | Feniseca tarquinius | Gossamer-winged Butterflies | 3 | Aug (past peak) |
| 46 | Swarthy Skipper | Nastra lherminier | Skippers | 3 | Aug (past peak) |
| 47 | Bronze Copper | Tharsalea hyllus | Gossamer-winged Butterflies | 3 | Jul (past peak) |
| 48 | Little Yellow | Eurema lisa | Whites, Yellows, and Sulphurs | 2 | Aug (past peak) |
| 49 | Meadow Fritillary | Boloria bellona | Brush-footed Butterflies | 2 | Jun (past peak) |
| 50 | Tawny Emperor | Asterocampa clyton | Brush-footed Butterflies | 2 | Jun (past peak) |