Predictions: Open-Meteo Marine (MeteoFrance SMOC, 0.08° grid) — heights relative to MSL (not chart datum / LAT). Model-derived.

Model-derived from a global ocean grid. Useful indication; expect about ±45 minutes on average vs. a local harmonic gauge, individual stations vary widely. See /methodology for per-region detail. Not for navigation.

Conditions as of 13:00 local time. Refreshes daily.

Predictions: Open-Meteo Marine (MeteoFrance SMOC, 0.08° grid) — heights relative to MSL (not chart datum / LAT). Model-derived. · Not for navigation.

The angler tradition that rates each day for fish-bite likelihood using moon transits and rise/set. One to five stars, not a scientific forecast.

• Mon
  ★★★★★
• Tue
  ★★★★★
• Wed
  ★★★★★
• Thu
  ★★★★★
• Fri
  ★★★★★
• Sat
  ★★★★★
• Sun
  ★★★★★

Next spring tide on Fri 01 May (range 1.1m). Last neap on Sun 26 Apr.

Spring tides cluster around new and full moons (biggest swings). Neap tides land on quarter moons (smallest swings). See the spring tide and neap tide glossary entries for the why.

Rio de Janeiro fronts the South Atlantic on Brazil's south-eastern coast, on the long curve of Guanabara Bay between the granite domes of Sugarloaf at the bay mouth and the Corcovado at its back, with Copacabana, Ipanema, and Leblon on the open Atlantic-facing south side and the working port and downtown on the bay side facing Niterói across the water. The Ilha Fiscal harbour gauge sits inside the bay near the historic Real Gabinete Português de Leitura. The tide here is a small mixed semidiurnal signal — two highs and two lows of unequal size each day, the asymmetry varying through the lunar month — with a mean range at the gauge of about 0.6 metres, climbing past 1.0 metre on the largest spring tides and dropping close to flat on neaps. The astronomical forcing is small because the South Atlantic at this latitude is broad and the continental shelf relatively narrow; the propagating tide reaches the coast as a near-progressive wave rather than building through resonance. What matters more on a day-to-day basis is wind setup from the south-quadrant frentes that sweep up from the South Atlantic — sustained 25-knot southerly winds can lift apparent water level 30 to 50 cm above predicted, and the same wind builds the famous Copacabana surf and the closeout shorebreak on the open Atlantic-facing beaches. Ipanema and Leblon read the swell more than the tide; Vermelha Beach at the foot of Sugarloaf, the protected swimming at Botafogo behind the bay headland, the long Niterói Beach at Icaraí across the water, the rocky intertidal at Arpoador where Ipanema meets Copacabana, and the Pedra do Telégrafo rocks in Barra de Guaratiba west of the city all read the table for different windows. The lowest spring lows around new and full moons open the rocky shelf at Pedra do Arpoador and the small tidepool zones at Forte de Copacabana for short windows. Open-Meteo Marine drives the gridded predictions on this page; for authoritative Brazilian tide data, the Marinha do Brasil's Centro de Hidrografia da Marinha (CHM) publishes the official tide tables and operates the Ilha Fiscal reference gauge.