Spring Tide: The highest tidal range, which occurs near the times of the new and full moons. It is rare and usually high tide
Neap Tide: The lowest tidal range, which occurs near the times of the first- and third-quarter phases of the Moon. They are weak tides.
Near the times of new and full moons, the Sun and Moon are aligned, and their forces are added together. The combined gravity of these two tide-producing bodies causes larger tidal bulges (higher high tides) and larger tidal troughs (lower low tides), producing a large tidal range. These are called the spring tides, which occur twice a month, during the time when the Earth-Moon-Sun system is aligned.
Neap tides occur at about the time of the first and third quarters of the Moon. At this time, the gravitational forces of the Moon and Sun act on Earth at right angles, and each partially offsets the influence of the other. As a result, the daily tidal range is less.
Spring tides occur twice every month, so they are not rare.