When are they ready.

You still have some weeks to go, maybe 6 or so.........certainly not 12! Being outdoors does not necessarily mean maturation takes longer, unless the weather starts getting very cold. Once there are 98-99% brown pistils/hairs, you will be entering the harvest zone. Nice plants for a first time grower!

Forgot to mention, hope you have at least a few months of warm weather left

well your outside so it will take longer. They look to have just finished the stretch so probably another 12 weeks. The white hairs you see will turn amber/brown everywhere and then another week or so at least. You have to keep an eye on trichomes being at least cloudy, again all over. Good luck

A lot of hairs will develop, the buds will begin to fatten up and the hairs will start turning brown. The trichomes will start to appear milky instead of clear, then begin to turn amber. The more amber you see the more mature the plant becomes. The smell intensifies as well. As far as when to harvest, as soon as you see amber and the hairs turn brown your in the window. It becomes a personal preference and what kind of high you’re looking for. A mind or body buzz or combination of both.

Once the calyxes plump around the hairs, it'll start to look like normal bud... start scoping trichomes (cheap 30-60x scope is fine)... at that point it is personal preference as to how much amber you see before you harvest - ripening is not the same pace throughout plant, so it's as much a guess as anything else. 10-70% amber? some like it early, some like it late... you'll have to figure that out. Bet you can find people that prefer nearly 100% amber, too.