Looks good.As good practice, I would also make the pins and interval constants.
Sorry - not quite with you. Are you referring to the 'long interval = 20000"? ...and as for the pins?
Do you mean, as opposed to 'long interval', write 'long const interval'? 'const interval' throws an error at me.
const unsigned long interval =
As for pins, what isn't quite best practice?
const int tempPin = 5;