Reading a tide table, rising and falling tide and slack water, how wind, waves and rain affect fishing, and when to call it off.
The main reason the same spot fishes well one day and not at all the next is the tide. When the tide moves, water flows, food moves with it and fish change their behavior. The tide is also directly tied to safety. Every year people walk out onto rocks or mudflats at low tide and are cut off when the water comes back in. Why tides happen is explained in the science topic's guide to moon phases and tides; this guide focuses on what to check before a trip and how to decide.
A tide table lists the times of high and low tide for each day and the tide height at those times. Most of the Korean coast has two high and two low tides a day, and those times shift about 50 minutes later each day on average. So a time that worked yesterday is no guarantee for today. Days with a big height difference are spring tides, days with a small one are neap tides, and they alternate roughly every two weeks. Local systems for numbering tide days differ by region, so reading the high and low times and heights directly is more reliable than the numbers.
The incoming tide is the flood, the outgoing tide is the ebb, and the period around high or low tide when the flow nearly stops is slack water. At many spots bites pick up as the water starts moving or when it runs strongly, and they tend to go quiet at slack water. Which phase is best, though, depends on the place and the fish. Local rules of thumb exist, such as shallow spots fishing better on the flood and deeper ones on the ebb, so fishing the same spot through different phases and keeping notes is the surest way to learn.
On spring tides the water moves a long way and currents are strong. Fish may be more active, but rigs drift and struggle to hold bottom, and the water reaches places that normally stay dry. On coasts with a large tidal range, such as Korea's west coast, the water comes in faster than you expect and the risk of being cut off grows. On neap tides the current is weak and rigs are easier to handle, but bites can be sluggish. If you are new, start on a day without extreme currents, around high tide, from a safe spot.
Wind changes both the quality of fishing and your safety. A headwind stops your rig from carrying and blows your line into tangles. A strong onshore wind makes it easy for waves to break over breakwaters and rocks. Before leaving, check wind direction, wind speed and wave height in the forecast, along with the marine forecast and any warnings. Swell generated far offshore can bring big waves even when the local wind is light, so do not relax just because it feels calm.
After rain, fresh water runs in, the water turns murky and its temperature changes, and bites change with it. In fresh water, rivers rise quickly after rain, so stay away from the edges. On days when the air temperature drops sharply, the water often cools too and fish become sluggish. Water temperature is a good indicator of seasonal change; checking recent trends in local reports helps you guess which fish will be around. If thunder starts, stop immediately: a rod can attract lightning. Collapse it and shelter in a building or car.
Make a habit of checking twice, the day before and the morning of the trip, because forecasts change. Even after arriving, leave earlier than planned if waves reach your feet or the wind keeps building. When it is hard to judge on your own, choosing not to fish that spot that day is the safe option.
Common mistakes are checking only the high tide time without confirming the way back from a spot you walked to at low tide, using a tide table from another region's station, and ignoring swell because the wind is light. Tides and weather raise the odds; they guarantee nothing. If the weather is poor or conditions are borderline, postponing the trip is how you protect the next one. For detailed marine and coastal information, rely on official sources such as the national weather service and the hydrographic office.
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