How to create a table with a time series?

Question

PostgreSQL

There is a weather forecast table.
100 cities and each has its own forecast for tomorrow, its own humidity and pressure
Everything is clear. The columns are City, temperature, humidity, pressure, date and fill in all cities in them.
But tomorrow we will have all new values ​​for each city. Where to fill them out? All in the same columns but with a different date? Is it right to do so?

Answer 1

The format you suggested is called fully denormalized. 100 records for every day is
a mere trifle for any popular database. Even if you are going to store data for 1000 years.
If you want to make access very, very fast, and your selection most often occurs by city and date, you can add a secondary key either to both fields, or only to the date.