The start time for the 2025 Daytona 500 was preponed by the association with inclement weather on the horizon. The broadcast was set to begin at 2:30 p.m. Eastern time but was then changed to 1:30 p.m. Eastern time. The race is at risk of receiving rainfall but a risk of postponement looks unlikely at the moment.
As per the latest weather reports, the chances of rain at noon on February 16, a couple of hours before the estimated green flag time is as low as 20%. However, it increases to 40% by the time the race starts and goes as high as 90% at 4 p.m. local time accompanied by thunderstorms.
The accurate information on whether the race will be postponed will only be received once it's close to the race time but as per NASCAR, the race will get finished before the thunderstorm hits the track, hence moving the race up by an hour.
NASCAR debuted the wet weather tires during the 2020 season, where they were first used at Charlotte Motor Speedway. The Cup Series has since then made use of the grooved tires on multiple road courses, but use of the wet tires on a Superspeedway is still prohibited.
This is because of the nature of a Superspeedway, where cars run minimal downforce, the average speeds are much higher, and hence a greater chance of a crash. For the same reason, the race was postponed to Monday for the 2024 Daytona 500.
If the track gets wet beyond a point where the cars cannot be run safely, then the race will be postponed. If the rain hits the Daytona 500 mid-race and then subsides quickly, then there will just be a small halt in the session, which is likely as the chances of rain drop from 90% to 40% at 5 p.m. local time.
“Tried to Download”: Dale Earnhardt Jr. on his team making the Daytona 500 debut

Justin Allgaier will be driving the No.40 JR Motorsports car at the Daytona 500 and will be starting the race P19 on the grid after finishing P9 in the first duel. Dale Earnhardt Jr spoke about the historic moment, fielding his car in the Daytona 500 for the first time, as he said, (via FOX)
“We have kind of tried to downplay how badly we want to race in the Cup Series. At least I have. It's like one of them things where you are like, ‘Man, if it's meant to be, it's meant to be.’”
"I'm not going to make it drag down all the other great things happening in my world, but man, we got here, and we got a taste of it. ... I didn't know exactly how badly I wanted to do this or wanted to be a part of something like this until we started going through it," Earnhardt Jr. added.
JR Motorsports is co-owned by Dale Earnhardt Jr., Kelley Earnhardt Miller, L.W. Miller, and Rick Hendrick, and will be fielding the No. 40 Chevrolet Camaro ZL1.