Acording to the Spirit annual she's a Paint mare.

Ritzuka:i got confused

I think she's a Paint. I have the DVD and I played a game on the CD rom, and It sayed she was an American Paint horse.

Well, this movie was made for all Kids, not just the horse lovers, so I woul dbelive she's a paint because that is probably the most regocnized spotted horse.

All we know is she is a skewbald or tobaino, or what most people have said just a paint. She could be anything really, various horse breeds can produce different colours, she could be a mixture of horses. No one probably knows for sure apart from the person who designed her.

i think shes a Paint. but to me her breed is beautiful.

Based on all of the comments, nobody may know for sure. I'll see if I can find out by watching the bonus features with background information on the disk again and see if they mention anything with the characters's breeds. But summing up with all of the comments, she's either an American Paint or a Mustang/Paint mix. (Judging by my opinion.)

she's not a paint, but she does have a pinto colored coat. she's a mustang: if you read the book series, her father is a full mustang and her mother is half mustang, half mystery breed (she's white so who knows what breed she is). so she's mostly mustang.

Rain is a Tobiano American Paint. Trust me, i did my research i have a paint horse fettish so of course a HAVE to love RAIN

it's obvious she a dinosour!