Future Tense

The always problematic verb 'to be'
has a middle voice future

It's starting to rain:
  is outside   Who?   will be inside  
ἔξω εἰμί   I ἔνδον σ ομαι 
εἶ   you (sg) σ ῃ/ει 
ἐστίν     he, she, it    σ ται 
ἐσμέν   we σ όμεθα 
ἐστέ  you (pl) σ εσθε 
εἰσίν they σ ονται