Examples
Meaning
There are two important 〜そうだ patterns. Appearance 〜そうだ means something looks a certain way or looks likely to happen. Hearsay 〜そうだ means the speaker heard or learned the information from another source.
Formation
Appearance 〜そうだ uses the verb ます-stem or adjective stem, such as 降りそうだ and おいしそうだ. Hearsay 〜そうだ uses the plain form, such as 降るそうだ and おいしいそうだ.
Usage
Use appearance 〜そうだ when judging by what you see now. Use hearsay 〜そうだ when reporting information from someone, news, a website, or another source.
Nuance
The two patterns can look very similar but their source of information is completely different. Appearance comes from visual impression. Hearsay comes from reported information.
Comparison
雨が降りそうです means it looks like it will rain. 雨が降るそうです means I heard it will rain. おいしそうです means it looks delicious. おいしいそうです means I heard it is delicious.
Common Mistakes
A common mistake is using the plain adjective before appearance そう. おいしいそうです usually sounds like hearsay, not appearance. For appearance, say おいしそうです.
Related Grammar
〜そうだ（様態）
〜そうだ in the appearance sense means something looks or seems a certain way based on what you can see now.
〜そうだ（伝聞）
〜そうだ in the hearsay sense means I heard that or it is said that. It reports information from another source.
〜らしい
〜らしい expresses inference from information or the idea that something is typical of someone or something.
〜そう・〜よう・〜みたい・〜らしいの違い
This comparison page organizes 〜そう, 〜よう, 〜みたい, and 〜らしい so learners can distinguish appearance, inference, hearsay, and typicality.