The postings and advice from my earlier question about trout fishing out west were great…thank you. While we we planning on late
June, it seems overwhelmingly that run off would greatly effect our trip. What would be best time to plan a trip to Montana, Coloroda or Yellowstone for my daughter and I…thank again.
I would pick mid July thru mid August if you had to do it in summer. If you can wait until September that would be better but for some people thats not an option. here are links to Montana’s snowpack and river flow rate web sites (or at least the websites I visit nearly every day)
[http://waterdata.usgs.gov/mt/nwis/current?type=flow[/url:093d9] you can check all states with this website
[url=“ftp://ftp.wcc.nrcs.usda.gov/data/snow/update/mt.txt”]ftp://ftp.wcc.nrcs.usda.gov/data/snow/update/mt.txt](http://waterdata.usgs.gov/mt/nwis/current?type=flow:093d9)
you will need to keep an eye on the flow rates if you choose a later date but hopefuly the snowpack will stay consistent and that wont be an issue this year.
hope this helps you out…you will probably get varying responses now that you are open to other times of the summer…and all of them will be good 
Take care everyone and cya around. Mark
Take a look at this web-site lots of information on it. If it were me I would go a little futher west than the Bighorn River to get the feel for Montana. You may take a few good fish there but I have to say there isn’t much to look at in the process. You will get a much better feel for Montana by going say from Big Timber west. If you want to look at a beautiful state while you fish. If it is all about fishing and not looking at a beautiful state then go anywere. Ron 
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If you can get away in the fall, I would suggest mid-September into mid-October. If summer is your time slot, I would also go with mid-July.
Ron is also correct about the Bighorn. It sure fishes well, but it isn’t the most scenic spot in Montana. It’s not terrible mind you, with the Pryor and Bighorn mountains in the background…
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William,
Run off is always an issue, as are local weather patterns.
You can go to the USGS website and find the snow levels and get some idea about run off, but it won’t help you much if a series of summer thunderstorms have blown out the particular river or stream you’ve decided to fish.
If you are going someplace to fish where you’ve not been before, it’s always best to contact a guide or ‘local’ source when you ARRIVE, and get some idea of what and where.
No one can ‘predict’ the fishing in advance, but you can rest assured that the local guides will be ‘on’ fish someplace.
There are enough folks here that if you post a query just prior to departure you can certainly get some kind of overview.
Good Luck!
Buddy