Explained: What is a neap tide and what is a spring tide?

The gravitational pull of the moon mainly controls our tides as it orbits Earth. There are two extremes of the tide: spring tide (sometimes referred to as ‘King’ tide) and neap tide. Spring tide essentially is the two tides where the sea is at its most extreme: the highest and lowest. In contrast, a neap tide is one where the difference between the high and low tides is at its lowest.

What is a spring tide?

The spring tide is when the sun and the moon align to create the greatest gravitational pull on the sea. This is because both the sun and the moon have combined greater gravitational force, which pulls the sea towards them. This means the side of the earth where both the sun and the moon align have the lowest tide, where the opposite side of the earth experiences the highest.

The diagram above shows the moon’s rotation around the Earth (red) and the Earth’s rotation around the sun (yellow). When the sun and the moon’s gravitational forces combine, they create the greatest tidal bulge (dark blue).

What is a neap tide?

When the sun and moon are at right angles to each other, there is the least gravitational pull, meaning the tidal range is at its lowest. The neap tide occurs 7 days after the spring tide.

Again, the diagram above shows the moon’s rotation around the earth (red) and the Earth’s rotation around the sun (yellow). When the sun and the moon’s gravitational forces are at right angles to each other, they create the least tidal bulge.

When is the next spring tide?

I've previously written about when all the spring (and neap) tides occur. Refer to this page to find out when the next spring tide is.

🌊 See when the next spring tide occurs

📅 Add spring and neap tides to your calendar

How often do spring tides occur?

Spring tides occur typically twice a month. Depending on how the months fall, some months sometimes see three. In a typical year, you can expect to see 25 spring tides. As such, the name 'spring' has nothing to do with the season; instead, their name comes from the old term 'springing forth'.

How often do neap tides occur?

Neap tides also occur typically twice a month. Spring tides usually follow a neap tide 7 days after a spring tide. It's believed the word 'neap' originates from an Anglo-Saxon word meaning 'scanty' or 'without power'.

Remember, even when there's a neap tide, the sea can be formidable and you should always check the tide times and the weather before heading out to sea.