Butterflies Flying in Washington in September (60 Species)

60 butterflies were recorded flying in Washington in September in our iNaturalist sample; 6 of the top 50 are at their peak this month. The list is ranked by number of research-grade observations.

Mar Apr May Jun Jul Aug Sep Oct

Top butterflies in September

Woodland Skipper566 obs.

Small White365 obs.

California Tortoiseshell228 obs.

Anna's Blue170 obs.

Orange Sulphur168 obs.

Green Comma135 obs.

Field Skipper134 obs.

Lorquin's Admiral133 obs.

Pine White128 obs.

Red Admiral121 obs.

Mylitta Crescent120 obs.

Juba Skipper119 obs.

All butterflies flying in Washington in September

#	Species	Scientific name	Family	Obs.	Peak in state
1	Woodland Skipper	Ochlodes sylvanoides	Skippers	566	Aug (past peak)
2	Small White	Pieris rapae	Whites, Yellows, and Sulphurs	365	Jul (past peak)
3	California Tortoiseshell	Nymphalis californica	Brush-footed Butterflies	228	Jul (past peak)
4	Anna's Blue	Plebejus anna	Gossamer-winged Butterflies	170	Aug (past peak)
5	Orange Sulphur	Colias eurytheme	Whites, Yellows, and Sulphurs	168	Sep (peak)
6	Green Comma	Polygonia faunus	Brush-footed Butterflies	135	Sep (peak)
7	Field Skipper	Atalopedes campestris	Skippers	134	Sep (peak)
8	Lorquin's Admiral	Limenitis lorquini	Brush-footed Butterflies	133	Jun (past peak)
9	Pine White	Neophasia menapia	Whites, Yellows, and Sulphurs	128	Aug (past peak)
10	Red Admiral	Vanessa atalanta	Brush-footed Butterflies	121	Jul (past peak)
11	Mylitta Crescent	Phyciodes mylitta	Brush-footed Butterflies	120	Jul (past peak)
12	Juba Skipper	Hesperia juba	Skippers	119	May (past peak)
13	Mormon Fritillary	Argynnis mormonia	Brush-footed Butterflies	118	Aug (past peak)
14	Hydaspe Fritillary	Argynnis hydaspe	Brush-footed Butterflies	110	Aug (past peak)
15	Coronis Fritillary	Argynnis coronis	Brush-footed Butterflies	104	Jul (past peak)
16	Gray Hairstreak	Strymon melinus	Gossamer-winged Butterflies	91	Aug (past peak)
17	Painted Lady	Vanessa cardui	Brush-footed Butterflies	89	May (past peak)
18	Hoary Comma	Polygonia gracilis	Brush-footed Butterflies	89	Aug (past peak)
19	Purplish Copper	Tharsalea helloides	Gossamer-winged Butterflies	83	Aug (past peak)
20	Common Ringlet	Coenonympha california	Brush-footed Butterflies	81	May (past peak)
21	Common Checkered-Skipper	Burnsius communis	Skippers	63	Jul (past peak)
22	Mourning Cloak	Nymphalis antiopa	Brush-footed Butterflies	62	Apr (past peak)
23	Satyr Comma	Polygonia satyrus	Brush-footed Butterflies	56	Apr (past peak)
24	Common Wood-Nymph	Cercyonis pegala	Brush-footed Butterflies	51	Jul (past peak)
25	Anise Swallowtail	Papilio zelicaon	Swallowtails and Parnassians	50	Jul (past peak)
26	Northern White-Skipper	Heliopetes ericetorum	Skippers	38	Sep (peak)
27	Western Tiger Swallowtail	Papilio rutulus	Swallowtails and Parnassians	37	Jun (past peak)
28	American Branded Skipper	Hesperia colorado	Skippers	36	Aug (past peak)
29	Acmon Blue	Icaricia acmon	Gossamer-winged Butterflies	32	May (past peak)
30	Western Pygmy-Blue	Brephidium exilis	Gossamer-winged Butterflies	31	Oct (rising)
31	Monarch	Danaus plexippus	Brush-footed Butterflies	30	Aug (past peak)
32	West Coast Lady	Vanessa annabella	Brush-footed Butterflies	30	May (past peak)
33	American Lady	Vanessa virginiensis	Brush-footed Butterflies	29	Sep (peak)
34	Viceroy	Limenitis archippus	Brush-footed Butterflies	26	Aug (past peak)
35	Western White	Pontia occidentalis	Whites, Yellows, and Sulphurs	25	Jul (past peak)
36	Clouded Sulphur	Colias philodice	Whites, Yellows, and Sulphurs	19	Aug (past peak)
37	Milbert's Tortoiseshell	Aglais milberti	Brush-footed Butterflies	18	Jul (past peak)
38	Rocky Mountain Parnassian	Parnassius smintheus	Swallowtails and Parnassians	18	Aug (past peak)
39	Clodius Parnassian	Parnassius clodius	Swallowtails and Parnassians	17	Jul (past peak)
40	Two-tailed Swallowtail	Papilio multicaudata	Swallowtails and Parnassians	17	Jul (past peak)
41	Melissa Blue	Plebejus melissa	Gossamer-winged Butterflies	17	Jun (past peak)
42	Sandhill Skipper	Polites sabuleti	Skippers	12	Aug (past peak)
43	Margined White	Pieris marginalis	Whites, Yellows, and Sulphurs	12	Jul (past peak)
44	Field Crescent	Phyciodes pulchella	Brush-footed Butterflies	11	Jul (past peak)
45	Echo Azure	Celastrina echo	Gossamer-winged Butterflies	10	Apr (past peak)
46	Snowberry Checkerspot	Euphydryas colon	Brush-footed Butterflies	10	Jul (past peak)
47	Becker's White	Pontia beckerii	Whites, Yellows, and Sulphurs	10	Jul (past peak)
48	Pale Swallowtail	Papilio eurymedon	Swallowtails and Parnassians	7	Jun (past peak)
49	Pacific Fritillary	Boloria epithore	Brush-footed Butterflies	6	Jul (past peak)
50	California Sister	Adelpha californica	Brush-footed Butterflies	5	Sep (peak)