The National Weather Service predicted a 100 percent chance of rain throughout the day, along with wind at gusts of up to 20 mph.
That would mean a soggy Preakness for Kentucky Derby winner Nyquist and the other 10 horses at the 6:45 p.m. ET start.
A torrential downpour at post time last year didn't ruin American Pharoah's run to the Triple Crown. Nyquist trainer Doug O'Neill seemed unfazed by the possibility of saddling up his horse in the rain, with the forecast including a 70 percent chance of showers at 6 p.m.
"With a horse like Nyquist, I'm not overly concerned about the weather," O'Neill said Friday. "As far as rain or shine, we're not going to change anything shoeing-wise. He's going to wear the same shoes he's got on. We'd just love to have a beautiful day."
Rain could be a good thing for several of his top rivals, though, especially Derby runner-up Exaggerator or long shot Cherry Wine. Both have run well in the mud, with Exaggerator taking the Santa Anita Derby on a sloppy track and Cherry Wine breaking his maiden by 9 lengths under similar conditions.
"I'll be one of the few people doing a rain dance," Cherry Wine's trainer, Dale Romans, said.
Nyquist, with an 8-0 record, won the Florida Derby over a surface listed as good even though the track had been drenched by a rainstorm before the race.
It's all the about the horseshoes for Preakness
Jeannine Edwards breaks down the importance of what horseshoes the horses racing in the Preakness are wearing for today's race