Conditions on this page are recalculated from the latest forecast every time it is opened, for the current date in the location's own time zone. Showing .
For most casual swimmers, 25–28°C (77–82°F) is the sweet spot — warm enough to stay in for an hour, cool enough to still refresh on a hot day. Trained swimmers and open-water enthusiasts prefer 20–24°C for sustained effort. Children and non-swimmers need 27–30°C to stay in comfortably. The Swim Comfort Score above adjusts the ideal band automatically based on the swimmer type you select. 20°C (68°F) is refreshing for confident adult swimmers — most stay in comfortably for 20–30 minutes without a wetsuit. For kids or casual swimmers, 20°C feels cold and sessions rarely exceed 10 minutes. Below 16°C, cold-water precautions apply for everyone: gradual entry, buddy system, and dry robe on exit. Below 15°C (59°F), cold-shock response can trigger involuntary gasping in the first 90 seconds — the single biggest drowning risk in cold water. Between 10–15°C, wetsuits are strongly advised; below 10°C, only trained cold-water swimmers should enter, and never alone. On the hot end, water above 32°C offers no cooling and can be dangerous for prolonged exertion. No — the ideal band depends on what you're doing. For a long training swim, 22–25°C prevents overheating. For a relaxed family beach afternoon, 27–29°C keeps everyone in. For competitive open-water races, FINA rules require water between 16°C and 31°C, with wetsuits mandatory below 18°C and prohibited above 20°C. A 0–100 score from a pure function with four inputs: water temperature, air temperature, wind speed, and wave height — weighted against the ideal band for your swimmer type (kids, casual, trained, open-water). The score starts at 70 (a good swim is the default) and each factor adds up to +18 or subtracts up to −55 (cold-shock territory). See the full formula in the methodology block below. Because the coldest moment of any swim is the exit. Air 15°C colder than water triggers rapid heat loss the moment you leave the pool or sea. The score penalizes air below 22°C and flags any air–water gap over 12°C as a shock-on-entry risk. Waves above 0.7m turn a relaxed swim into constant effort and make it unsafe for kids. Above 1.2m, the score treats open-water swimming as caution territory; above 2m, avoid. Sheltered pools and coves stay swimmable in bigger surf offshore. The Persian Gulf, the Indian Ocean around the Maldives, and the tropical Pacific consistently record 28–31°C peak water temperatures. The Caribbean peaks at 29–30°C in August–September. Our destinations table below ranks 12 popular swim destinations by peak-month water temperature. Late August is the annual peak across most of the Med: Nice, Barcelona and the Balearics hit 24–26°C; the Aegean and southern Turkey reach 26–27°C. September stays warm and much less crowded — often the smartest swim window in Europe. May and June are cool for casual swimmers (18–22°C). Yes — Cyprus, Malta, and southern Crete stay above 17°C through winter, warm enough for trained swimmers. For casual swimmers, only the Canary Islands (18–23°C year-round) reliably deliver comfortable water 12 months a year within Europe. Without a wetsuit, 18°C is the practical lower bound for a comfortable session over 20 minutes for most casual swimmers. With a 3mm wetsuit, that drops to about 14°C. With a 5mm wetsuit and gloves, trained swimmers can extend to single-digit water — but always with a support boat or shore team. It depends on water temperature and your tolerance. A general rule: 20°C+ no wetsuit for most adults; 16–20°C wetsuit optional for long sessions; below 16°C wetsuit strongly recommended; below 12°C wetsuit mandatory. Kids benefit from wetsuits above these thresholds because they cool 2–3× faster than adults. An involuntary gasp reflex triggered by sudden immersion in water below ~15°C. It causes rapid breathing you can't control for 60–90 seconds, and is the primary cause of cold-water drownings. Prevention: enter slowly, exhale through the mouth, never jump in, and always swim with a buddy in water below 18°C. Rough guide without a wetsuit for a confident adult: 28°C — indefinite; 24°C — 60–90 minutes; 20°C — 30–45 minutes; 16°C — 10–15 minutes; 12°C — 3–5 minutes maximum. Kids should halve every duration. Trained cold-water swimmers extend these substantially with acclimatization.
Scores are capped by dealbreakers — heavy rain, dangerous wind, thick fog or hazardous UV pull a day down no matter how pleasant the rest of the numbers look. Forecast data is Open-Meteo; solar and lunar values are computed for Best Water Temperature For Swimming's own coordinates and time zone. Full details on the methodology page.