Get a soil sample done.
Price of product and the amount ( if any) of rainfall you get can make you a winner or loser.
Around here they want you to buy a year ahead and then they always offer my big neighbouring outfits a way better deal than me which annoys me so I seed lots of legumes instead.
Even with rain the price I get offered for N doesn't pencil out for cow hay. Maybe it would for small squares and team roper or horse guys.
Depends a lot on how old your grass stand is. A younger stand will produce way better with N than an older sod bound run out stand.
Loose your shirt with no rain.
What kind of grass do you have?