Uptime is an aggregate of over a thousand validators' opinions, with each having their own view of the network. So all numbers are an approximation.
Each 3rd party explorer gets their information by asking a subset of validators for their opinion. Each validator forms their opinion independently.
The best practice would be to check and monitor your own node for a more accurate estimate of uptime.
To learn more about the Avalanche Consensus please read the following article.
For any additional questions, please view our other knowledge base articles or contact a support team member via the chat button. Examples are for illustrative purposes only.