As of just a few minutes ago Google started sending out these warnings.
This is an update on existing warnings that went live earlier this year. Google has said that it will work to get more site owners taking up HTTPS by increasing it as a ranking signal and through measures like this. I have not yet seen the warnings on login forms like the one below.
I managed to see this because I use the beta version of chrome with the security flags set to show this. Presumably this is what we will see in October, although I’m not sure about them coloured red as the general Chrome not secure warning is still grey. Maybe in October this will turn red.
If you’re a retailer it looks like the time is up for moving fully to HTTPS. A lot of retailers and publishers have not implemented HTTPS sitewide and simply use it on carts and logins. If the “Not Secure” warning does go red in October that will kill conversions for a lot of retailers.
Have you seen any red warnings yet? Would this change be enough to make you implement HTTPS?