Is it too early?

I think you should sit back, wait a bit, and tone down the excitement...it's too early and no need to panic when you see fare fluctuations. I personally think you can do better than $2200-2500 but it's up to you as to what you're willing to pay. I usually travel in Sept/October and get better fares than this (caveat, I'm very flexible with timing, airline choice, and seating arrangements).

My best advice is simple (almost too simple)...just set a fare you're willing to pay in your mind and once you see it, just buy it and be OK with the outcome. Right now, the fare appears too high - so the only choice is to wait and not panic. I don't think there is a magical window to buy tickets - only when the ticket price matches what you're willing to pay, nothing else really matters.

There are sites that will email when the fare drops, hipmunk being one of them.

You have to watch prices over a long period before you can adequately "know" if a price is bad, good or fantastic. What is your "ticket window"? You mean when your tickets can actually physically be purchased? Don't know what airline you're flying but for example our tickets for June 2016 were purchased WAYYYY back in 2015..probably around August or September. I knew it was a fantastic price so there was no question (and it's double now).

There is no magical crystal ball predictor for airfares so this thing about "travel experts suggest to book 4-5 months out..." is nonsense. The fares appear whenever they appear. You've just got to be knowledgeable about the prices so you'll know when to pull the trigger. Don't rely on "travel experts" for that kind of advice.

I don't think it is normal, but it is hard to know what "normal"'is these days.

I just checked the British Airways low fare calendar and it shows exactly what you describe: fares from Newark to London (RT because that is what the calendar shows) are $1850 for two people through the summer ( June, July, and August), and then jump to $2550 for two in September. And it stays high after that.

I am not good at advising on airfare because we fly on miles, but my instinct says to wait.

The prices you're looking at are right around what we have to pay out of Minneapolis (economy coach) but I'd think you could do a bit better from the East Coast. Give it awhile?

Try flights.google.com. i put in your dates and see round trip fares for $866 pp, nonstop JFK-LHR and then CDG-LHR-JFK

https://www.google.com/flights/#search;iti=EWR,JFK,LGA_LHR,LGW,LCY,STN,LTN,QQS_2016-09-12*CDG,ORY,BVA,XHP,XPG_EWR,JFK,LGA_2016-09-26;tt=m;sel=JFKLHR0VS112,CDGLHR0BA309-LHRJFK0VS45

Those fares sound extremely high to me. Are you looking at economy or economy plus? If it's economy...what are you looking at? Very specific times or something? I can't fathom fares that high for economy from NY to London/Paris. I'm seeing non-stops on British Air for around $1150 for the 12 - 26 of September. Other airlines are cheaper, as are flights with stops.

It is not too early to book, fares may come down but then again they may not. Book when you see a good rate. $2500 is NOT a good rate for economy. I don't fly from NY much, but I'd say consider anything under $1300, but I'd get more advice from people who fly from there often as to what is possible.

Mira the price she's quoting is for two adults I believe.

I go to europe usually once every year or skip one, and I have always booked my airline tickets 6-10 months in advance. I get good prices.

September is not considered shoulder season in Paris. September is still high season, and hotel rate are higher then than they are for most of July and August, so personally I would book airline ticket soon so I could reserve my hotel of choice, the good ones with reasonable prices get booked up for Sept well in advance.