Turkey · Climate data from the Turkish State Meteorological Service
Istanbul dresses for a 13°C–28°C / 55°F–82°F window across the months we cover. Istanbul is east-meets-west — the only city straddling two continents, and the dressing register reflects it. Religious sites (Hagia Sophia, Blue Mosque, Süleymaniye Mosque) require shoulders and knees covered + head covering for women in active mosques (head scarves provided at the entrance). Summer 21-28°C / 70-82°F with low rain frequency. Beyoğlu (the European side, around İstiklal Caddesi) runs contemporary international; Sultanahmet (the Old City) is tourist-historical; Karaköy is creative/design; Kadıköy on the Asian side is local-favored. Walking surfaces include both modern pavement and old cobblestones; supportive shoes essential.
Across the 4 months we cover: morning lows from 13°C / 55°F (May) to afternoon highs of 28°C / 82°F (July).
What to wear in Istanbul in May: MGM data (21°C / 70°F, 7 rain days), Hagia Sophia + Blue Mosque dress codes, and the Beyoğlu-Karaköy contemporary register.
What to wear in Istanbul in June: MGM data (26°C / 79°F, 7 rain days), summer arrives, mosque dress codes continue, and the Bosphorus rooftop dining rhythm.
What to wear in Istanbul in July: MGM data (28°C / 82°F, 5 rain days), peak summer heat with Bosphorus humidity, mosque dress codes, and the Beyoğlu evening uniform.
What to wear in Istanbul in August: MGM data (28°C / 82°F, 5 rain days), peak summer continues, the Bosphorus humidity rules, and the late-summer Karaköy register.
The neighborhood you sleep in affects what reads as appropriate more than the calendar does. Istanbul's style scene anchors on the districts below — each leaf page calls out the local register (smart-casual, undone, technical, party) so the capsule maps to the streets you'll actually walk on.
Every leaf page on this hub is built from four data layers: climate normals from the Turkish State Meteorological Service; named-authority etiquette and style references (Vogue, Condé Nast Traveler, Business of Fashion, the relevant local press); resident write-ups and traveler-forum reports for the failure modes tourists get wrong; and the editorial avatar pool that visualises each capsule on a person rather than a moodboard. Every DO names a reason. Every DON'T names a failure mode. We retest before each seasonal refresh — the editorial-modified date at the bottom of each leaf is the receipt.
Climate numbers come from the Turkish State Meteorological Service — the national meteorological service for Turkey. Daily highs and lows, rain days, and daylight hours are 1991–2020 normals — the international standard, refreshed every decade. Capsule pieces and what-to-avoid notes are stress-tested against Istanbul resident write-ups, named-stylist sources where the city has a documented uniform (Vogue Paris under Emmanuelle Alt for Paris, Vogue Japan and i-D Tokyo coverage for Tokyo, NYMag's The Cut for New York), and the failure modes locals actually flag in city forums and traveler reports.
Because the morning-low to afternoon-high swing inside one Istanbul month already changes the silhouette — and the swing between months is much bigger than that. May mornings start at 13°C / 55°F; July afternoons hit 28°C / 82°F. A single packing list that tries to span both ends up wrong at both. Each month here is a different capsule, calibrated to the climate band that actually shows up on the ground.
4 so far: May, June, July, August. There is no cap on months per city — we are working through the calendar, and a month is only worth publishing when it has its own thesis, so no two adjacent months here share a capsule piece or an illustration. Months we haven't written yet are gaps in the schedule, not judgments that the month isn't worth covering.
The the Turkish State Meteorological Service figures cited on every Istanbul leaf are 1991–2020 normals — the international standard, refreshed every decade. We restate the numbers as raw averages on the leaf pages ("28°C / 82°F afternoons") rather than the year range, so the figures don't read as stale. The next normals refresh covers 2001-2030 and lands in 2031 — we'll bump every page when it does. MGM publishes Istanbul normals across three representative stations — Kadıköy, Florya and Sarıyer — rather than one city figure.
Editorial rule, enforced in CI: every DO line names a specific reason ("merino sinks under a trench so a damp morning doesn't show through your knit"); every DON'T names a specific failure mode ("suede stains the first time light drizzle catches it"). We ban "timeless," "elevate your style," "must-have," and "effortless" — they're the giveaway phrases of generic AI fashion writing. If a sentence could open any city's guide, it gets cut. Istanbul's guide reads like Istanbul, not like a packing-list aggregator.