When do you start collecting rainwater in the spring?

I live in the inland northwest and we have several months of below freezing weather.  However, I would like to capture snow melting off the roof in early spring when it still freezes hard at night, as this is a major source of water and we have very arid summers.

Does anyone have any rules of thumb for when to start and stop collecting rainwater in above ground tanks, with relation to the temperatures or first/last frost dates?

Thanks!

Not being in a cold climate I have not idea when to start collecting snow melt-off.  My guess would be when there are signs that the night temp is just slightly below freezing or when the daytime temps are slightly above.

Here are some threads that might offer some suggestions:

https://permies.com/t/42371/collect-water-winter-frozen

https://permies.com/t/154923/ground-rainwater-system-cold-climate

https://permies.com/t/139938/Freezing-temps-rain-barrels

Thanks!

It also depends greatly on your tank design.  Some can handle freezing, some can't.

I would, if the space and law allows, build a pond to maximize retention and pump it into the tanks after the threat of freezing is over to minimize evaporation.  Buy an above ground pool from Craigslist or Wal-Mart clearance, it is a LOT of water holding per dollar. Or build your own with billboard tarps.  

We kept a 45gal barrel of water all winter this year.  It was a pretty mild winter for the most part (still freezing, but lots of freeze thaw cycles), but we did have a stretch of -15C or so for a couple (few?) weeks. As long as we kept breaking the ice on top of the barrel, it was fine. You just don't want the top to freeze solid and have nowhere for the water underneath to expand as it freezes.

If you've got some way of breaking up ice, I'd start collecting as soon as it started melting. The danger of having it all freeze gets less and less as time goes on and you build up more water. I guess it depends on how big your tanks are, how much water is going into them, what kind of freezing you're expecting to get, etc.