Jellyfish at Koh Nang Yuan

เกาะนางยวน · Koh Tao · Gulf of Thailand

Risk today · 25 Oct 2026Moderate

Main factor: Stronger wind than usual

Conditions or reports nearby make an encounter more likely.

Today the jellyfish risk at Koh Nang Yuan Beach is moderate. Main factor: stronger wind than usual. In October it is usually moderate here. It is an estimate, not a guarantee: follow beach flags and lifeguards.

What to expect today

5-day outlook

  1. TodayModerate5 m/s SW — Wind: up to 5 m/s, blowing from SW. The arrow shows where it blows to. Onshore wind pushes jellyfish to the beach.0.1 m — Waves: up to 0.1 m during the day. Strong onshore waves wash jellyfish ashore; box jellyfish prefer calm water.4 mm — Rain: 4 mm in the day. Box jellyfish are more common near river mouths after heavy rain.
  2. TomorrowModerate6 m/s SE — Wind: up to 6 m/s, blowing from SE. The arrow shows where it blows to. Onshore wind pushes jellyfish to the beach.0.5 m — Waves: up to 0.5 m during the day. Strong onshore waves wash jellyfish ashore; box jellyfish prefer calm water.4 mm — Rain: 4 mm in the day. Box jellyfish are more common near river mouths after heavy rain.
  3. Tue 27Moderate7 m/s E — Wind: up to 7 m/s, blowing from E. The arrow shows where it blows to. Onshore wind pushes jellyfish to the beach.0.5 m — Waves: up to 0.5 m during the day. Strong onshore waves wash jellyfish ashore; box jellyfish prefer calm water.8 mm — Rain: 8 mm in the day. Box jellyfish are more common near river mouths after heavy rain.
  4. Wed 28Moderate8 m/s E — Wind: up to 8 m/s, blowing from E. The arrow shows where it blows to. Onshore wind pushes jellyfish to the beach.0.4 m — Waves: up to 0.4 m during the day. Strong onshore waves wash jellyfish ashore; box jellyfish prefer calm water.10 mm — Rain: 10 mm in the day. Box jellyfish are more common near river mouths after heavy rain.
  5. Thu 29Low7 m/s E — Wind: up to 7 m/s, blowing from E. The arrow shows where it blows to. Onshore wind pushes jellyfish to the beach.0.3 m — Waves: up to 0.3 m during the day. Strong onshore waves wash jellyfish ashore; box jellyfish prefer calm water.51 mm — Rain: 51 mm in the day. Box jellyfish are more common near river mouths after heavy rain.
  6. Fri 30Low7 m/s E — Wind: up to 7 m/s, blowing from E. The arrow shows where it blows to. Onshore wind pushes jellyfish to the beach.0.3 m — Waves: up to 0.3 m during the day. Strong onshore waves wash jellyfish ashore; box jellyfish prefer calm water.24 mm — Rain: 24 mm in the day. Box jellyfish are more common near river mouths after heavy rain.

Why this level

  • Box jellyfish Moderateraises risk
    above usual for the season · stronger wind than usual · rain
  • Other jellyfish and stinging plankton Moderateraises risk
    above usual for the season · waves toward the shore · stronger wind than usual
  • Bluebottles (Portuguese man o’ war) Lowlowers risk
    below usual for the season

October is an average month for jellyfish on the Samui archipelago, the wind blows from the sea (~2.6 m/s), stronger than usual, the sea is calm (waves ~0.1 m), so the risk level is moderate. There are no recent jellyfish reports.

Recent reports

No recent reports.

Report jellyfish

At this beach now? Your report helps others. "No jellyfish today" is useful too.

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Seasonality

Bars show the baseline seasonal risk for this coast; dots show official warnings nearby by month.

Koh Nang Yuan: jellyfish month by month

  1. January: Usually moderate risk. High risk on 0% of days. Onshore wind on 4% of days. Official warnings: 0. Eyewitness reports: 1.
  2. February: Usually moderate risk. High risk on 3% of days. Onshore wind on 3% of days. Official warnings: 0. Eyewitness reports: 1.
  3. March: Usually moderate risk. High risk on 6% of days. Onshore wind on 12% of days. Official warnings: 0.
  4. April: Usually moderate risk. High risk on 0% of days. Onshore wind on 39% of days. Official warnings: 0.
  5. May: Usually moderate risk. High risk on 0% of days. Onshore wind on 66% of days. Official warnings: 0.
  6. June: Usually moderate risk. High risk on 0% of days. Onshore wind on 99% of days. Official warnings: 0.
  7. July: Usually moderate risk. High risk on 19% of days. Onshore wind on 98% of days. Official warnings: 0.
  8. August: Usually moderate risk. High risk on 10% of days. Onshore wind on 99% of days. Official warnings: 0. Eyewitness reports: 2.
  9. September: Usually moderate risk. High risk on 1% of days. Onshore wind on 98% of days. Official warnings: 0. Eyewitness reports: 3.
  10. October: Usually moderate risk. High risk on 14% of days. Onshore wind on 54% of days. Official warnings: 0. Eyewitness reports: 2.
  11. November: Usually moderate risk. High risk on 9% of days. Onshore wind on 18% of days. Official warnings: 0. Eyewitness reports: 1.
  12. December: Usually moderate risk. High risk on 6% of days. Onshore wind on 0% of days. Official warnings: 0.
  • Low
  • Moderate
  • High
  • Very high

Colour shows the typical risk level that month; the number is the share of high-risk days. Warnings and sightings are in each month’s tooltip.

Coordinates: 10.1172, 99.8130

Questions and answers

Can I swim at Koh Nang Yuan today?

Today's estimated risk is moderate; main factor: stronger wind than usual. It is an estimate, not a guarantee: "no reports" does not mean there are no jellyfish. Check beach flags and follow lifeguards.

Have jellyfish been seen at Koh Nang Yuan recently?

No reports in the last 14 days. It is an estimate, not a guarantee: "no reports" does not mean there are no jellyfish. Check beach flags and follow lifeguards.

In which months are jellyfish more likely at Koh Nang Yuan?

Based on 2022–2026 weather, the risk is most often elevated in July, August, September. Official warnings nearby: 0.

Who do I call after a jellyfish sting?

Emergency medical services in Thailand: 1669 (free). Alert the beach lifeguard; if a box jellyfish is possible, pour vinegar over the sting for at least 30 seconds.