I would recommend changing the Ionian Boots of Lucidity to Sorcerers Shoes.

This is because you get 15% CDR from Athene's Unholy Grail, 20% from Morrello's Evil tome and the Ionian Boots of Lucidity given another 15%.
Combined with your mastery's this gives 56% CDR and the cap is 40%.

So if you remove the 15% from Ionian Boots of Lucidity that makes it 41% which is only 1% over cap and you get a little spell pen to counter enemy runes and mastery's.

Either that or take Boots of Swiftness and always out-run your enemies when combining this with her passive!

LOVE IT

I like your build for the most part, althought there are a few things I disagree with. However I just do not think that there is enough gold for essentially an AP carry build and an AD carry in bot lane. Even with 2 gold per 10 items I don't think it's viable. Now if this was a Janna mid guide then I would probably vote up this guide. As I said though, I don't believe this would work as a support build.

^

the only problem i have with this build is that it's very VERY hard to get all those items as a 0 cs support :S
also, you said that your heals and shields are not enough to save someone, while that is true, they should have not died in the first place, it's their own fault for getting out of position, so don't blame yourself.
Oh, the above thing does not go for tanks :P
anyway, +1

nice

I win every ranked game I play with Janna, using this guide. It just makes sense man. I used to play her as bringing Auras and interrupts, but now I'm getting effective aoe healing and my tornados are hitting pretty hard to boot. :)

good build my first game was 10/2/18 :D. I love Janna .

Sorry, but I just can't upvote an AP Janna build for all the obvious reasons

Awesome build! I use it and I love it!

I like the item build, but all potency runes might hinder her survivability, regardless of her shield.

Awesome build! I love how much more powerful my shield and heals are this way :)