By time of year

How season helps identification

Time of year is one of the fastest traits for narrowing the search. Many species fly only in a set period: one group in early spring, another in mid-summer, a third in autumn. A butterfly in late March is almost certainly an overwintered adult; one in early August is likely a second summer generation.

Use this guide together with identification by colour and by place of encounter.

Note: flight periods shift by 1–2 weeks depending on year and region. Dates refer to central Russia (Moscow ±400 km). In the south (Krasnodar) everything is 2–4 weeks earlier; in the north (Saint Petersburg, Urals) 1–2 weeks later.

March — first early species

The first butterflies appear above 8–10 °C — usually late March, sometimes earlier. These are species that overwinter as imago: they survived winter as adults, hidden in bark crevices, sheds, and attics.

What you may see:

• Brimstone (Gonepteryx rhamni) — male bright yellow; female pale greenish. First mass spring butterfly. Overwintered as adult, hidden among leaves.
• Small tortoiseshell (Aglais urticae) — orange with black spots. Emerges from hibernation at the first warmth.
• European peacock (Aglais io) — red-brown with “eyes”. Emerges with the tortoiseshell.
• Mourning cloak (Nymphalis antiopa) — dark brown with a pale yellow border. Overwintered in bark crevices; appears early, feeds on flowering willow.
• Comma (Polygonia c-album) — ochre-brown with ragged margins; less conspicuous but also early.

April — first “new” butterflies

In April overwintered species are joined by the first butterflies from pupae and eggs of the new season.

New species in April:

• Map butterfly (Araschnia levana, spring generation) — small, russet with a dark pattern; very unlike the summer generation
• Orange tip (Anthocharis cardamines) — white with orange patch in male; female without orange; flies at edges with bittercress
• Black-veined white (Aporia crataegi) — white with dark veins; first individuals by late April
• Winter moth (nocturnal) — males can still be found from autumn

April is the best time to watch the first active flights of brimstones by flowering willow and dandelions.

May — peak of spring diversity

The richest “spring” month. Host plants leaf out; overwintered species fly actively and the first summer species appear.

What flies in May:

• All overwintered species (brimstone, tortoiseshell, peacock, mourning cloak) — in the first half of the month
• Black-veined white — white clouds on garden edges
• Orange tip — peak flight in the first half of May
• Map butterfly, spring generation — russet spring form
• Small heath (Coenonympha pamphilus) — first generation
• Blues — first generation of many species, especially common blue (Polyommatus icarus)
• Green hairstreak (Callophrys rubi) — bright green below; in shrubs
• Checkerspots — checkered, May
• Mnemosyne (Parnassius mnemosyne) — late May in the Caucasus and Altai

June — peak species diversity

The richest month of the year. All spring species fly; second generations of many species begin; summer species start.

Characteristic species in June:

• Old World swallowtail (Papilio machaon) — first generation; on umbellifers (carrot, dill)
• Scarce swallowtail (Iphiclides podalirius) — yellow-white with dark stripes and long tails
• Apollo (Parnassius apollo) — white with red eyespots; mountains and limestone slopes
• Fritillaries — large russet nymphalids with silver below
• Red admiral (Vanessa atalanta) — first migrants
• Satyrines — meadow brown, ringlet
• Clouded yellows (Colias) — yellow and orange
• Map butterfly, summer generation — dark with white spots (second generation, unlike the spring form)

July — peak abundance

July has the highest number of individuals with slightly fewer species than June. Second flight peak for many species.

Characteristic species in July:

• Painted lady (Vanessa cardui) — migrant; mass flights in “good” years
• Second generation of blues, whites, checkerspots
• Grayling (Minois dryas) — large dark satyrine with blue eyespots
• Purple emperor (Apatura iris) — male with blue sheen; floodplain forest
• Admirals — poplar, white
• Ringlets (Erebia) — peak in mountains
• Second generation of tortoiseshell, peacock

August — late summer, start of hibernation

Species diversity drops. Some species are already in diapause (pupa, egg, caterpillar); adults that overwinter prepare for dormancy.

What is active in August:

• Painted lady — migrates south by month’s end
• Red admiral — feeds on overripe fruit (plums, pears)
• Tortoiseshell, peacock — second generation; enter hibernation by late August
• Second generation of swallowtail, clouded yellows
• Satyrines — small heath, meadow brown still flying
• In mountains — last ringlets and apollos

August is good for watching thistle, burdock, and buddleia: painted lady, admiral, and checkerspots gather there.

September — late species

Only the hardiest and latest species are active. Nights are cold, days still warm — butterflies bask on heated stones and trunks.

What you may find:

• Brimstone — active while temperature stays above 10 °C; hibernates under leaves
• Tortoiseshell, comma — until frost
• Red admiral — last individuals on warm days; some migrate
• Clouded yellows — late generation still flies in the first half of September

October–November — winter geometrids

Day-flying butterflies are gone, but in October–November specific overwintering geometrid moths fly:

• Winter moth (Operophtera brumata) — males fly at freezing temperatures; females wingless, crawl on tree trunks. Look on oak and apple trunks in November with a torch.
• Autumnal moth (Epirrita autumnata) — slightly earlier, October.

Summary table by month

Two-brooded species: identification caution

Some species have two generations per year that look very different:

Map butterfly (Araschnia levana): spring generation russet with a dark pattern, like a small fritillary; summer generation dark brown with a white band, like a small admiral. They are often taken for two species.

Many blues: the spring brood is smaller and duller than the summer brood.

If a butterfly does not match the usual look — check whether it is another seasonal generation.

More on seasonality — in butterfly life cycle and how butterflies overwinter.