SeasonMapAlgae & red tide, month by month around the world
Blooms that close beaches and clear the water of fish for a few weeks; not the Caribbean weed.
This is a warning page, not a recommendation. Algae & red tide covers 10 destinations on SeasonMap; the months below are the ones in which the risk window is open — most weeks in them pass quietly, and the score beside each place is still the ordinary climate score, hazard and all.
When it is on
Number of destinations with algae & red tide on in that month. Windows move a little each year.
Algae & red tide in January
- 🇺🇸 Naples, Florida, United StatesRed tide risk · 1 Sep – 28 Feb (usually)Blooms of Karenia brevis drift onto this coast most often between autumn and late winter.91climate
- 🇺🇸 Sarasota, United StatesRed tide · 1 Sep – 1 Mar (usually)Blooms of Karenia brevis drift inshore in some years, killing fish and putting an irritant in the air along the beach.85climate
- 🇺🇸 Tampa, United StatesRed tide season · 1 Sep – 28 Feb (usually)Karenia brevis blooms usually start offshore in the autumn and drift onto the Gulf beaches, killing fish and leaving an aerosol that has people coughing on the sand.84climate
- 🇺🇸 Clearwater, United StatesRed tide · 1 Aug – 28 Feb (usually)Blooms drift in most often from late summer into winter, killing fish and putting an irritant in the air that makes the beach unpleasant within minutes.81climate
Algae & red tide in February
- 🇺🇸 Sarasota, United StatesRed tide · 1 Sep – 1 Mar (usually)Blooms of Karenia brevis drift inshore in some years, killing fish and putting an irritant in the air along the beach.92climate
- 🇺🇸 Tampa, United StatesRed tide season · 1 Sep – 28 Feb (usually)Karenia brevis blooms usually start offshore in the autumn and drift onto the Gulf beaches, killing fish and leaving an aerosol that has people coughing on the sand.90climate
- 🇺🇸 Clearwater, United StatesRed tide · 1 Aug – 28 Feb (usually)Blooms drift in most often from late summer into winter, killing fish and putting an irritant in the air that makes the beach unpleasant within minutes.89climate
- 🇺🇸 Naples, Florida, United StatesRed tide risk · 1 Sep – 28 Feb (usually)Blooms of Karenia brevis drift onto this coast most often between autumn and late winter.88climate
- 🇵🇭 Boracay, PhilippinesGreen algae on White Beach · 15 Feb – 31 May (usually)A fringe of green weed, locally lumot, grows along the shallows in the hot months and is raked off each morning.70climate
Algae & red tide in March
- 🇺🇸 Sarasota, United StatesRed tide · 1 Sep – 1 Mar (usually)Blooms of Karenia brevis drift inshore in some years, killing fish and putting an irritant in the air along the beach.90climate
- 🇵🇭 Boracay, PhilippinesGreen algae on White Beach · 15 Feb – 31 May (usually)A fringe of green weed, locally lumot, grows along the shallows in the hot months and is raked off each morning.74climate
Algae & red tide in April
Algae & red tide in May
- 🇨🇳 Qingdao, ChinaGreen algae bloom · 20 May – 15 Aug (usually)Ulva drifts up the Yellow Sea most summers, peaks around June and comes ashore in a green mat that the city clears with diggers.92climate
- 🇺🇸 Austin, United StatesBlue-green algae on the lake · 15 May – 31 Oct (usually)The city posts warnings for toxic cyanobacteria on Lady Bird Lake through the warm months.69climate
- 🇵🇭 Boracay, PhilippinesGreen algae on White Beach · 15 Feb – 31 May (usually)A fringe of green weed, locally lumot, grows along the shallows in the hot months and is raked off each morning.63climate
Algae & red tide in June
- 🇮🇹 Rimini, ItalyMucilage and algal blooms · 15 Jun – 31 Aug (usually)The northern Adriatic is shallow and warm and in some summers it produces mucilage, a brown gel that clings to swimmers and shuts the water for a few days.86climate
- 🇨🇳 Qingdao, ChinaGreen algae bloom · 20 May – 15 Aug (usually)Ulva drifts up the Yellow Sea most summers, peaks around June and comes ashore in a green mat that the city clears with diggers.78climate
- 🇺🇸 Austin, United StatesBlue-green algae on the lake · 15 May – 31 Oct (usually)The city posts warnings for toxic cyanobacteria on Lady Bird Lake through the warm months.59climate
Algae & red tide in July
- 🇵🇱 Sopot, PolandBlue-green algae closures · 5 Jul – 31 Aug (usually)A hot, still fortnight turns the shallow Bay of Gdańsk soupy and the sanitary inspectorate closes beaches to swimming — sometimes for days, sometimes most of August.87climate
- 🇮🇹 Rimini, ItalyMucilage and algal blooms · 15 Jun – 31 Aug (usually)The northern Adriatic is shallow and warm and in some summers it produces mucilage, a brown gel that clings to swimmers and shuts the water for a few days.79climate
- 🇨🇳 Qingdao, ChinaGreen algae bloom · 20 May – 15 Aug (usually)Ulva drifts up the Yellow Sea most summers, peaks around June and comes ashore in a green mat that the city clears with diggers.56climate
- 🇺🇸 Austin, United StatesBlue-green algae on the lake · 15 May – 31 Oct (usually)The city posts warnings for toxic cyanobacteria on Lady Bird Lake through the warm months.49climate
Algae & red tide in August
- 🇵🇱 Sopot, PolandBlue-green algae closures · 5 Jul – 31 Aug (usually)A hot, still fortnight turns the shallow Bay of Gdańsk soupy and the sanitary inspectorate closes beaches to swimming — sometimes for days, sometimes most of August.92climate
- 🇮🇹 Rimini, ItalyMucilage and algal blooms · 15 Jun – 31 Aug (usually)The northern Adriatic is shallow and warm and in some summers it produces mucilage, a brown gel that clings to swimmers and shuts the water for a few days.79climate
- 🇨🇳 Qingdao, ChinaGreen algae bloom · 20 May – 15 Aug (usually)Ulva drifts up the Yellow Sea most summers, peaks around June and comes ashore in a green mat that the city clears with diggers.53climate
- 🇺🇸 Clearwater, United StatesRed tide · 1 Aug – 28 Feb (usually)Blooms drift in most often from late summer into winter, killing fish and putting an irritant in the air that makes the beach unpleasant within minutes.52climate
- 🇺🇸 Pensacola, United StatesRed tide risk · 1 Aug – 15 Dec (usually)Karenia brevis blooms drift along the Gulf coast in late summer and autumn in some years, killing fish and putting an irritant in the air along the shore.51climate
- 🇺🇸 Austin, United StatesBlue-green algae on the lake · 15 May – 31 Oct (usually)The city posts warnings for toxic cyanobacteria on Lady Bird Lake through the warm months.47climate
Algae & red tide in September
- 🇺🇸 Austin, United StatesBlue-green algae on the lake · 15 May – 31 Oct (usually)The city posts warnings for toxic cyanobacteria on Lady Bird Lake through the warm months.66climate
- 🇺🇸 Pensacola, United StatesRed tide risk · 1 Aug – 15 Dec (usually)Karenia brevis blooms drift along the Gulf coast in late summer and autumn in some years, killing fish and putting an irritant in the air along the shore.62climate
- 🇺🇸 Clearwater, United StatesRed tide · 1 Aug – 28 Feb (usually)Blooms drift in most often from late summer into winter, killing fish and putting an irritant in the air that makes the beach unpleasant within minutes.59climate
- 🇺🇸 Sarasota, United StatesRed tide · 1 Sep – 1 Mar (usually)Blooms of Karenia brevis drift inshore in some years, killing fish and putting an irritant in the air along the beach.58climate
- 🇺🇸 Tampa, United StatesRed tide season · 1 Sep – 28 Feb (usually)Karenia brevis blooms usually start offshore in the autumn and drift onto the Gulf beaches, killing fish and leaving an aerosol that has people coughing on the sand.57climate
- 🇺🇸 Naples, Florida, United StatesRed tide risk · 1 Sep – 28 Feb (usually)Blooms of Karenia brevis drift onto this coast most often between autumn and late winter.55climate
Algae & red tide in October
- 🇺🇸 Austin, United StatesBlue-green algae on the lake · 15 May – 31 Oct (usually)The city posts warnings for toxic cyanobacteria on Lady Bird Lake through the warm months.81climate
- 🇺🇸 Pensacola, United StatesRed tide risk · 1 Aug – 15 Dec (usually)Karenia brevis blooms drift along the Gulf coast in late summer and autumn in some years, killing fish and putting an irritant in the air along the shore.80climate
- 🇺🇸 Tampa, United StatesRed tide season · 1 Sep – 28 Feb (usually)Karenia brevis blooms usually start offshore in the autumn and drift onto the Gulf beaches, killing fish and leaving an aerosol that has people coughing on the sand.70climate
- 🇺🇸 Sarasota, United StatesRed tide · 1 Sep – 1 Mar (usually)Blooms of Karenia brevis drift inshore in some years, killing fish and putting an irritant in the air along the beach.70climate
- 🇺🇸 Clearwater, United StatesRed tide · 1 Aug – 28 Feb (usually)Blooms drift in most often from late summer into winter, killing fish and putting an irritant in the air that makes the beach unpleasant within minutes.69climate
- 🇺🇸 Naples, Florida, United StatesRed tide risk · 1 Sep – 28 Feb (usually)Blooms of Karenia brevis drift onto this coast most often between autumn and late winter.66climate
Algae & red tide in November
- 🇺🇸 Pensacola, United StatesRed tide risk · 1 Aug – 15 Dec (usually)Karenia brevis blooms drift along the Gulf coast in late summer and autumn in some years, killing fish and putting an irritant in the air along the shore.88climate
- 🇺🇸 Clearwater, United StatesRed tide · 1 Aug – 28 Feb (usually)Blooms drift in most often from late summer into winter, killing fish and putting an irritant in the air that makes the beach unpleasant within minutes.85climate
- 🇺🇸 Tampa, United StatesRed tide season · 1 Sep – 28 Feb (usually)Karenia brevis blooms usually start offshore in the autumn and drift onto the Gulf beaches, killing fish and leaving an aerosol that has people coughing on the sand.82climate
- 🇺🇸 Sarasota, United StatesRed tide · 1 Sep – 1 Mar (usually)Blooms of Karenia brevis drift inshore in some years, killing fish and putting an irritant in the air along the beach.82climate
- 🇺🇸 Naples, Florida, United StatesRed tide risk · 1 Sep – 28 Feb (usually)Blooms of Karenia brevis drift onto this coast most often between autumn and late winter.78climate
Algae & red tide in December
- 🇺🇸 Sarasota, United StatesRed tide · 1 Sep – 1 Mar (usually)Blooms of Karenia brevis drift inshore in some years, killing fish and putting an irritant in the air along the beach.88climate
- 🇺🇸 Tampa, United StatesRed tide season · 1 Sep – 28 Feb (usually)Karenia brevis blooms usually start offshore in the autumn and drift onto the Gulf beaches, killing fish and leaving an aerosol that has people coughing on the sand.87climate
- 🇺🇸 Naples, Florida, United StatesRed tide risk · 1 Sep – 28 Feb (usually)Blooms of Karenia brevis drift onto this coast most often between autumn and late winter.84climate
- 🇺🇸 Clearwater, United StatesRed tide · 1 Aug – 28 Feb (usually)Blooms drift in most often from late summer into winter, killing fish and putting an irritant in the air that makes the beach unpleasant within minutes.84climate
- 🇺🇸 Pensacola, United StatesRed tide risk · 1 Aug – 15 Dec (usually)Karenia brevis blooms drift along the Gulf coast in late summer and autumn in some years, killing fish and putting an irritant in the air along the shore.74climate