Maybe rather than just look at the weather today, go back and look at the climate normals for each city/region...Also check out any stations you can find in the higher elevations (e.g., Banff or Canmore just west of Calgary) if you are looking to cross any mountains. Probably not advisable from about mid-October onwards for the northern Rockies.
I did look at the weather, but it doesn't help me well. I saw only sun and rain no snow, around 9°C. Rain like 2mm it's not that much, so anyway it give idea but nothing like real information from local.
Yep to that. Look at what the normal weather is for a particular place for a particular month. Wikipedia is a good spot, since they usually have climate summaries for major cities.
For example, for February, the average high in Vancouver, BC is 8.2C/46.8F, the average low is 4.9C/40.8F, and average rainfall is 98.9mm/3.894in. Not horrible, but not great either. Here in Portland, OR, it's slightly better with an average high temp of 51F/10C and an average 3.68in/93.5mm of rain.
Factor in short days where it may rain on and off all day, ending up at a wet campround by 4pm so you can set up before dark, long dark nights, and gear and clothing being damp all the time because you'll never get enough time to dry them out. I ride all year in Portland, and I don't mind riding in the rain, but I end up in a warm and dry house every day.
Also, another thing to note is that the inland cities will be DRIER than the actual coast
. That's because the Coast Range/Olympic Mtns/Vancouver Island mountains block a good deal of the precipitation from hitting the inland. But the coast gets the brunt. For example, Astoria, Oregon is on the coast about 160km/100mi from Portland. The average high temp for February is 51F/10C, but the rain is 7.19 in/182.6. That's DOUBLE of what you'd see in already damp Vancouver! And Forks, WA on the Olympic coast gets 10.35 inches/262.9mm in February!
And finally, the prevailing wind along the coast in the winter is from the southwest. If you head south, it means you'll likely be getting a headwind the whole time.
This is what you'd face with a bike tour down the Northwest Coast in February. Sure, you will get some good days, but the odds are that you will see more bad days.