Butterflies Flying in California in September (60 Species)

60 butterflies were recorded flying in California in September in our iNaturalist sample; 9 of the top 50 are at their peak this month. The list is ranked by number of research-grade observations.

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Top butterflies in September

Monarch6,724 obs.

Fiery Skipper6,197 obs.

Gulf Fritillary3,780 obs.

Gray Hairstreak3,149 obs.

Woodland Skipper2,636 obs.

Gray Buckeye2,571 obs.

Small White2,515 obs.

Umber Skipper2,405 obs.

Western Giant Swallowtail2,184 obs.

Painted Lady1,972 obs.

California Sister1,904 obs.

Anise Swallowtail1,887 obs.

All butterflies flying in California in September

#	Species	Scientific name	Family	Obs.	Peak in state
1	Monarch	Danaus plexippus	Brush-footed Butterflies	6,724	Jul (past peak)
2	Fiery Skipper	Hylephila phyleus	Skippers	6,197	Sep (peak)
3	Gulf Fritillary	Dione vanillae	Brush-footed Butterflies	3,780	Sep (peak)
4	Gray Hairstreak	Strymon melinus	Gossamer-winged Butterflies	3,149	Aug (past peak)
5	Woodland Skipper	Ochlodes sylvanoides	Skippers	2,636	Sep (peak)
6	Gray Buckeye	Junonia grisea	Brush-footed Butterflies	2,571	Jun (past peak)
7	Small White	Pieris rapae	Whites, Yellows, and Sulphurs	2,515	Jul (past peak)
8	Umber Skipper	Lon melane	Skippers	2,405	May (past peak)
9	Western Giant Swallowtail	Heraclides rumiko	Swallowtails and Parnassians	2,184	Sep (peak)
10	Painted Lady	Vanessa cardui	Brush-footed Butterflies	1,972	Apr (past peak)
11	California Sister	Adelpha californica	Brush-footed Butterflies	1,904	Jun (past peak)
12	Anise Swallowtail	Papilio zelicaon	Swallowtails and Parnassians	1,887	Jun (past peak)
13	Marine Blue	Leptotes marina	Gossamer-winged Butterflies	1,348	Jul (past peak)
14	Acmon Blue	Icaricia acmon	Gossamer-winged Butterflies	1,218	Jul (past peak)
15	Western Pygmy-Blue	Brephidium exilis	Gossamer-winged Butterflies	1,188	Oct (rising)
16	Lorquin's Admiral	Limenitis lorquini	Brush-footed Butterflies	1,148	Jun (past peak)
17	Mournful Duskywing	Erynnis tristis	Skippers	1,103	Aug (past peak)
18	West Coast Lady	Vanessa annabella	Brush-footed Butterflies	1,052	Apr (past peak)
19	Mylitta Crescent	Phyciodes mylitta	Brush-footed Butterflies	1,047	Jun (past peak)
20	Common Checkered-Skipper	Burnsius communis	Skippers	920	Oct (rising)
21	Behr's Metalmark	Apodemia virgulti	Metalmark Butterflies	872	May (past peak)
22	American Lady	Vanessa virginiensis	Brush-footed Butterflies	855	Jul (past peak)
23	Red Admiral	Vanessa atalanta	Brush-footed Butterflies	747	Apr (past peak)
24	Western Tiger Swallowtail	Papilio rutulus	Swallowtails and Parnassians	718	Jun (past peak)
25	California Tortoiseshell	Nymphalis californica	Brush-footed Butterflies	643	May (past peak)
26	Orange Sulphur	Colias eurytheme	Whites, Yellows, and Sulphurs	608	Oct (rising)
27	Checkered White	Pontia protodice	Whites, Yellows, and Sulphurs	521	Jun (past peak)
28	Northern White-Skipper	Heliopetes ericetorum	Skippers	490	Jun (past peak)
29	Field Crescent	Phyciodes pulchella	Brush-footed Butterflies	426	Jun (past peak)
30	Common Ringlet	Coenonympha california	Brush-footed Butterflies	422	Apr (past peak)
31	Eufala Skipper	Lerodea eufala	Skippers	377	Sep (peak)
32	Field Skipper	Atalopedes campestris	Skippers	366	Sep (peak)
33	Mourning Cloak	Nymphalis antiopa	Brush-footed Butterflies	339	Apr (past peak)
34	Cloudless Sulphur	Phoebis sennae	Whites, Yellows, and Sulphurs	335	Sep (peak)
35	Sandhill Skipper	Polites sabuleti	Skippers	326	Jul (past peak)
36	Purplish Copper	Tharsalea helloides	Gossamer-winged Butterflies	229	Oct (rising)
37	Queen	Danaus gilippus	Brush-footed Butterflies	226	Oct (rising)
38	Dainty Sulphur	Nathalis iole	Whites, Yellows, and Sulphurs	217	Sep (peak)
39	White Checkered-Skipper	Burnsius albezens	Skippers	216	Oct (rising)
40	Fatal Metalmark	Calephelis nemesis	Metalmark Butterflies	197	Jul (past peak)
41	California Patch	Chlosyne californica	Brush-footed Butterflies	177	Oct (rising)
42	Great Purple Hairstreak	Atlides halesus	Gossamer-winged Butterflies	134	Oct (rising)
43	Ceraunus Blue	Hemiargus ceraunus	Gossamer-winged Butterflies	122	Jun (past peak)
44	Coronis Fritillary	Argynnis coronis	Brush-footed Butterflies	119	Jun (past peak)
45	Funereal Duskywing	Erynnis funeralis	Skippers	110	Mar (past peak)
46	Hoary Comma	Polygonia gracilis	Brush-footed Butterflies	108	Jul (past peak)
47	Sleepy Orange	Eurema nicippe	Whites, Yellows, and Sulphurs	106	Oct (rising)
48	Satyr Comma	Polygonia satyrus	Brush-footed Butterflies	103	Jun (past peak)
49	Large Orange Sulphur	Phoebis agarithe	Whites, Yellows, and Sulphurs	100	Sep (peak)
50	Pale Swallowtail	Papilio eurymedon	Swallowtails and Parnassians	90	Jun (past peak)