Here in SoCal, if its raining its cold, so no. I put them in their houses and shut them in. In other areas, like AZ, FL or HI, they have warm rain, so I would leave them out.
If it is warm weather/summer time and the weather is not "cold" where you are ...and the torts will not drown where they are housed...and have a good place to retreat to ....then yes, they are fine....it is ok if a tortoise gets rained on.....now in winter months when it is wet/cold winter weather....no, not so much. Warm and a little rain okay....cool/cold and rain/wetness not good....