When you say "same again" is it because they repeated or is it because you were expecting them to alternate?
With rand_number() you're not guaranteed to have one outcome after the other, they have a 50% chance of happening but that's it, they can repeat.
If you want to have your code alternating results then you need to set a variable (probably a global in your code?) and have the weather use it as a check as you see necessary.