# How to use Tide99

US NOAA tide predictions, observed water levels and station-level marine conditions, each with its own timestamp.

## Start with a precise record

Use the name, identifier or place you want to investigate. The website scope is: US NOAA tide predictions, observed water levels and station-level marine conditions, each with its own timestamp.

## Compare like with like

Open the relevant records and guides below. Keep identifiers, geography, units and source dates together; a record with a similar name or a different reporting period may answer a different question.

## Take the evidence to the original source

Follow the source references before making a consequential decision. Treat missing or historical information as a limitation, and use the relevant authority or provider for a current determination.

## Tools and records

- [Start a search on tide99.com](https://tide99.com/)

## Question guides

- [What does high tide and low tide mean?](https://tide99.com/task-guides/what-does-high-tide-and-low-tide-mean/index.md)
- [What tide is safest to swim in?](https://tide99.com/task-guides/what-tide-is-safest-to-swim-in/index.md)

Source: https://tide99.com/ (first-party website; inspected 2026-10-17).