King Tides & Sea Level Rise

King tides refer to the highest tides that occur over the course of a year when the gravitational pull of the sun and moon reinforce each other. These tides, also known as perigean spring tides, occur when the moon is closest to the Earth. Learn more about tides and tide cycles.

When king tides occur during cyclones, floods or storms, water levels can rise to higher levels and have the potential to cause great damage to property and the coastline.

(credit: NOAA)

King tides aren’t part of climate change; they are a natural part of tidal cycles but they offer a sneak preview of what higher sea levels could look like. The actual height reached by a king tide will depend on the local weather and ocean conditions on the day.

It is possible that by 2060 we could experience tides of the magnitude of king tide events every month due to sea-level rise induced by climate change.

This project aims to promote awareness of the impacts of sea level rise, and help to visualize coastal areas that are vulnerable to tidal inundation which can be monitored over time.

Learn more about sea level rise.  To read about the highest astronomical tides along the coast of Maine and how these are mapped, go to

To enter the annual Gulf of Maine King Tides Photo Contest, click on this site’s “Add Your Photos” page.

To submit photos throughout the year for statewide mapping in Maine, New Hampshire and Massachusetts, go to

Anecdata, an online citizen science portal, also has a King Tides Project where citizens can contribute photos.