Margaret,
You can specify lots of different conditions in the label of a Branch step, and combine them as necessary using &&, ||, etc. You can even use regular expressions in them!
In your case, I’d probably first extract the day of the month and hour from your timestamp as separate variables (maybe DoM and hour). Then, in the label of your Branch step, check that ‘DoM = 1 && hour > 0 && hour < 3’. Something like that, you get the point. HTH.
#Integration-Server-and-ESB#webMethods#Flow-and-Java-services