Travel between UK and Portugal in Schengen area

As US citizen I am able to be here in UK for 180 days out of 360 days from my date of arrival. On Dec 7 I leave UK after being here for 176 days  I am traveling to Italy and Portugal -in Schengen area where I can be 3 months within a 6 month period.   

I need some clarification on how to best travel between Schengen area countries and UK or non-Schengen area over a 2 year period.
Can I be in Italy for one month, and then travel to Portugal for two months, then return to UK for three months, beginning a new 6 month stay in one year, and then return to  Italy for three months, and return to UK for three months?
When does the Schengen area (90 days within 180 days) start in the Italy?  Portugal?

I have heard that it is possible to be in a Schengen country for 3 months, stay in a non-Schengen area country for a few days and then, when I return to Schengen area it begins a new 6 month period.   Is this really possible?!

enpai wrote:

I have heard that it is possible to be in a Schengen country for 3 months, stay in a non-Schengen area country for a few days and then, when I return to Schengen area it begins a new 6 month period.   Is this really possible?!


this is possible but it's not legal. Some people get away with it, some get caught. But the count of your stay in Schengen starts when you arrive in the first country. So, if you fly to Italy and stay there for 30 days, you only have 60 days allowance for Portugal before you have to leave and be somewhere non-Schengen for 90 days.

I know people who've gotten into trouble with the authorities by not realizing the clock starts in the first Schengen country you land in, and that it's not a per-country allowance.

thanks for the info ECS. 
'But the count of your stay in Schengen starts when you arrive in the first country.'
Yes this is my original understanding that the clock starts when I arrive in first Schengen country.  It does seem a bit risky to me.  I also understand that it depends on the Schengen country and the immigration officer.   For example Switzerland, NL, Germany, Poland, Scandanavian countries are much stricter checking the entry dates than Spain, Greece, France, Italy.  I have also heard, directly from Belgian immigration officer that being female, on US passport and over 60 is also to my benefit so not to worry about overstaying in Schengen area. 

Any way I think it best to stay within the regulations, or as close to them as possible to reduce any potential problems.  :)

yeah, you are probably not considered a high risk population, but you really never know. You say Scandinavia is more strict but I went into Iceland many times as a resident without being asked to show my residency documentation. I showed my passport that clearly showed me spending lots of time in Schengen and they never asked. Other times I've had to show everything and been questioned about my job and residency. I'm white, female, and in my 30s.

getting into trouble with this regulation does have the possibility to make it difficult to return easily to such a large part of the world that I at least wouldn't want to get on the wrong side of immigration authorities.