INDEX MATCH MATCH in a temperature correction chart

[Snnej]

Hello all,
I am new to the forum. I have been working for days on this. Please help if you can. I am working with a temperature correction chart. I think I should be using INDEX MATCH MATCH to get my desired results. the uploaded chart is what I'm working with.

Thank you in advance!
Snnej

[BMV]

=INDEX($A$4:$A$207,MATCH(X5,INDEX($B$4:$S$207,,MATCH(X6,$B$3:$S$3,)),-1))
remember about round.

[Snnej]

Awesome! Thanks so much!