When is the best time to sow a useful tool is the sowing caclulator, or creating a calendar to keep for your record. To be more precise is possible to refer to the weather and temperatures, but you need to be a bit experienced to do so.
The sowing calculator doesn’t require any specific knowledge and is perfect for your kick start! After a while you will like to get more info and here you’ll need a table, somethng more specific, like this:
And if you realise that you are really into it, then think of a notepad with your sowing history, or go more tech with an App as Sowing Calendar!