How Many Spring Tides Are There in a Month? A 2025 Guide

The short answer: in most months there are two spring tides — one around the new moon and one around the full moon. So when people ask how many spring tides there are in a month, the standard answer is two, though a small number of calendar months can squeeze in a third because the Moon’s cycle doesn’t line up neatly with the calendar. This guide explains the timing, why the count varies, and what it means for the tides you actually see at the coast.

What Causes a Spring Tide?

A spring tide is not named after the season. It comes from the old English sense of “springen,” meaning to leap up. These are the tides with the largest range between high and low water, and they happen when the Sun and Moon line up so their gravitational pulls reinforce each other.

That alignment occurs twice per lunar cycle: at the new moon (Sun and Moon on the same side of Earth) and again at the full moon (Sun and Moon on opposite sides). Because the Moon takes about 29.5 days to return to the same phase, these alignments are spaced roughly two weeks apart, according to the NOAA National Ocean Service.

Spring tides are not a sudden event on one day. The enhanced range builds for a day or two, peaks near the alignment, then eases off. Most people notice the biggest highs and lowest lows across a window of two to three days around each new and full moon.

Spring Tides vs. Neap Tides

Halfway between the spring tides come the neap tides, when the Sun and Moon pull at right angles and partly cancel each other out. Neap tides have the smallest range — weaker highs and higher lows than usual.

So a typical lunar month runs: spring tide, neap tide, spring tide, neap tide. Two of each, alternating roughly every week. If you remember nothing else, remember that rhythm.

How Many Spring Tides in a Month, Exactly?

On the astronomical clock, the answer is almost always two. But the calendar is a human invention, and the Moon doesn’t care about it, which is where the edge cases come from.

Here is what drives the count:

• Lunar month length: About 29.5 days between successive new moons, so two alignments (new and full) nearly always fall inside one calendar month.
• Calendar month length: Months run 28 to 31 days. February is the shortest and is the main reason counts can shift.
• Timing of the alignments: If a new moon falls on the 1st or 2nd of a 31-day month, it is possible for a third spring tide to begin near the very end of that same month.

The practical consequence: most months give you two clear spring tide periods, but occasionally a month will show three, usually with the third arriving right at the start of the next lunar alignment.

A Worked Example

Imagine a new moon on the 1st of a 31-day month. That new moon brings a spring tide early in the month. Around the 15th, the full moon brings the second spring tide. Then, near the 30th, the next new moon arrives — and its spring tide falls just inside the same calendar month. That gives three spring tide periods instead of the usual two.

Nothing unusual has happened to the ocean. The tides follow the Moon, and the month simply caught three alignments instead of two.

When Do Spring Tides Happen?

The pattern is regular enough that you can predict spring tides a long time ahead: they cluster around the new moon and the full moon, roughly every 14 days. Tide tables published by national authorities list predicted high and low water times and heights for specific locations, and the largest ranges tend to appear a day or two after the alignment rather than exactly on it.

A useful detail is that spring tides are typically strongest around the equinoxes in spring and autumn, when the Sun is above the equator and its tidal contribution adds more effectively to the Moon’s. The National Oceanography Centre notes that tidal ranges vary widely by location, so the height you see depends heavily on where you are as well as on the phase of the Moon.

Why the Coast Doesn’t Feel It Differently

Two spring tides per month does not mean two dramatic events a month everywhere. In some places, such as parts of the Mediterranean, tidal ranges are naturally small, so the difference between spring and neap tides is modest. In places with large ranges, such as the Bay of Fundy or the Bristol Channel, the spring-neap difference is much more noticeable.

That is why local tide tables matter far more than a general rule. The general rule gives you the timing; the table gives you the numbers.

What Spring Tides Mean in Practice

If you spend time near the water, the twice-monthly rhythm is worth knowing. Spring tides push high water further up beaches and into estuaries, and pull low water further out, exposing more shoreline. That affects several things at once:

• Coastal flooding risk: Higher high water can combine with storm surge or heavy rain to raise flood risk, especially around the equinoxes.
• Boating and fishing: Stronger currents and greater depth changes around spring tides change how boats sit at anchor and how fish move.
• Beachcombing and rockpooling: The lowest spring tides expose the widest stretch of shore, which is why they are popular for exploring.
• Swimming and surfing: Larger tidal range can shift rip currents and change conditions quickly.

For anything safety-critical — planning a passage, a coastal event, or a flood defence — check the official tide predictions for your location and, where relevant, consult a qualified local authority or marine professional rather than relying on a general rule of thumb.

Key Takeaways

• There are almost always two spring tides in a month, one near the new moon and one near the full moon.
• Occasionally a calendar month contains three spring tide periods, typically when alignments fall near the start and end of a 31-day month.
• Spring tides alternate with neap tides roughly every week, following a lunar cycle of about 29.5 days.
• The largest tidal ranges often occur a day or two after the new or full moon, not exactly on it.
• Spring tides are generally strongest near the spring and autumn equinoxes.
• Local geography matters enormously — always check tide tables for your specific location.