Springs and Neaps

When the Sun and Moon align (new moon and full moon), their gravitational pulls combine, producing spring tides — the highest highs and lowest lows. When the Sun and Moon are at right angles (first and third quarter), their pulls partially cancel, producing neap tides — smaller range between high and low.

The spring/neap cycle takes about 14 days (half a lunar month). Spring tides occur a day or two after the new and full moons. Tidal range at springs can be double or more compared to neaps.