These are the best Sigma lenses with weather-sealing when you want dependable, sealed mechanics, crisp optics, and field-ready handling for rain, dust, spray, and temperature swings—across full frame and APS-C—and here’s what to look for as you buy: prioritize a “dust- and splash-resistant structure” (gasketed mount plus internal ring seals), fluorine-coated front elements for easy wipe-down, robust switches with positive detents, internal zoom/focus (best for balance and sealing) or at least tight extending barrels, effective stabilization (OS) that pairs with IBIS, customizable AFL buttons and focus limiters you can operate with gloves, tripod collars with weather-safe feet, and consistent filter sizes so you keep one weather-rated CPL/VND; also consider operating temperature, serviceability, and weight you’ll actually carry when storms hit. Sports-line glass is Sigma’s most rugged: 70–200mm f/2.8 DG DN OS | Sports (sealed, superb OS, event/sideline workhorse), 150–600mm f/5–6.3 DG DN OS | Sports (field king with dual OS modes and custom switches), 60–600mm f/4.5–6.3 DG DN OS | Sports (one-lens flexibility from pits to small birds), 500mm f/5.6 DG DN OS | Sports (prime reach, light enough to hike, terrific sealing), plus DSLR-era stalwarts that adapt well—120–300mm f/2.8 DG OS HSM | Sports, 70–200mm f/2.8 DG OS HSM | Sports, 150–600mm DG OS HSM | Sports—when you need proven weather armor. Art-series mirrorless lenses bring real-world sealing without the bulk: 14–24mm f/2.8 DG DN | Art (tank-tough ultra-wide for storms and spray), 24–70mm f/2.8 DG DN | Art (sealed mid-range with close-focus for detail cuts), 14mm f/1.4, 20mm f/1.4, and 24mm f/1.4 DG DN | Art (night/landscape primes with weather-resistant structures for dew and drizzle), 35mm f/1.4 and 50mm f/1.4 DG DN | Art (low-light heroes with gaskets and minimal breathing for hybrid work), 85mm f/1.4 DG DN | Art (portrait staple, sealed and lighter than DSLR glass), and the 105mm f/2.8 DG DN Macro | Art (1:1 detail with gasketed mount, great for dewy mornings). Contemporary-line winners with practical sealing include the 16–28mm f/2.8 DG DN | C (compact, threaded front, weather-resistant), 17–50mm f/2.8 DG DN | C (small, close-focusing mid-range with sealing), 100–400mm f/5–6.3 DG DN OS | C (travel-light tele with gasket and coatings), and the I-Series primes—17mm f/4, 20mm f/2, 24mm f/2, 35mm f/2, 45mm f/2.8, 65mm f/2, 90mm f/2 DG DN | C—which pair metal barrels with gasketed mounts and punchy micro-contrast for stormy travel sets. APS-C shooters get sealed convenience in the 10–18mm f/2.8 DC DN | C (tiny, threaded, weather-resistant) and can pair it with full-frame DN OS teles for rugged mixed kits; DSLR classics like the 24–105mm f/4 DG OS HSM | Art and 105mm f/2.8 EX DG OS Macro offer basic sealing and are strong values adapted to mirrorless. Practical buyer tips: if you regularly work in rain/spray, lean Sports for maximum sealing and internal design, standardize front diameters (77/82mm) for one weather-rated CPL/VND, choose fluorine-coated fronts if you shoot surf or snow, and pack a lens hood—it’s a real weather accessory; for hybrid shooters, DG DN Art primes/zooms balance sealing, AF speed, and controlled breathing; travelers can build a fully sealed, lightweight trio with 16–28/2.8 C + 24–70/2.8 A + 100–400 C or swap in I-Series primes. Field care and shooting tips: keep a hydrophobic cloth in a dry pocket, wipe front elements front-to-back (not circular) to avoid smearing, use rain covers for downpours but trust the gaskets for drizzle, let cold-soaked lenses acclimate in a sealed bag to prevent condensation, enable OS for steadier storm light (disable on a locked tripod if you see drift), and favor internal-zoom lenses on gimbals and monopods in foul weather. Whether you’re covering a wedding in coastal mist, tracking wildlife through dust, or shooting blue-hour cityscapes in a steady rain, the best Sigma weather-sealed lenses combine stout gaskets, sensible ergonomics, and crisp, color-true optics—so you keep shooting confidently when the forecast says “don’t.”