This app was mentioned in 6 comments, with an average of 1.67 upvotes
Hourly forecasts have their use.
If it's showing rain all day, you can bank on that.
50% chance of Scattered showers? That's a gamble.
In that case, use the weather radar and make your own prediction based on your route. See if there's rain in the area and which direction it's moving.
I like https://www.wunderground.com on desktop and RadarNow! on Android.
Radar Now... https://play.google.com/store/apps/details?id=com.usnaviguide.radar_now
All it does is display public information (radar images from NOAA and warnings/alerts from the NWS). But, it is simple, easy, and doesn't require an account or any personal information. It doesn't even ask your location unless you tell it to center the map on where you are.
I like RadarNow! I like how it keeps everything as raw as possible. RadarNow!
I've been using this one for a while, https://play.google.com/store/apps/details?id=com.usnaviguide.radar_now&hl=en_US
I use radarnow with good success; https://play.google.com/store/apps/details?id=com.usnaviguide.radar_now&hl=en
For webcams related to Santiam Pass-http://www.skimountaineer.com/MtnWebCams/Santiam-MtnWebCams.html?size=med&telemetry=true
For cameras around Oregon-https://www.tripcheck.com/Pages/CamerasEntry.asp
For broad mountain weather information-https://www.tripcheck.com/Pages/CamerasEntry.asp -For more in depth information go down to the map at right click on a specific road or area.
If you check all 3 of these together it gives you the most accurate information.
For weather on the go the most accurate cell app I've found to see what's going on is Radar Now:
Android-https://play.google.com/store/apps/details?id=com.usnaviguide.radar_now
iPhone-https://itunes.apple.com/us/app/radarnow!-weather-radar/id634139673?mt=8
Source-I go from Corvallis to Bend/Sisters 30/40 times each Winter and have for years.