Cinque Terre

It would help to know which of the five towns you'd prefer to stay in? Also are you looking for a hotel, a B&B or just a room?

For travel in September, I'd suggest booking as SOON as you can! It may be difficult at this late date to find any vacancies. I'd suggest looking in Monterosso first as it's the largest of the five towns and therefore has the greatest number of accommodations. If you can't find anything in the five towns, you could also try Levanto, as it's only about four minutes by train from Monterosso.

How long will you stay in the Cinque Terre? Where are you arriving from? Where will you be going after that?

What's your budget?

You may have trouble finding an affordable place to stay this late. Consider Levanto, the next village north of Monterosso on the train line, as an alternative to staying in one of the five villages. Trains run all the time, a few per hour during the day, between Levanto an the five villages, and Levanto itself is a nice town, even not quite of the "built into the side of a hill" appeal of the five villages. I've stayed in Levanto twice.

Hop on Booking.com to see what you can find this late. Use the map feature.

If money were no object, I'd probably stay in Vernazza, Riomaggiore, or Manarola. Corniglia is probably more quiet because it's up the hill from its train station (there are shuttle buses, but people might not like to wait or to walk up) and has no boat dock for the tourist boats. Monterosso is bigger than the others and feels too much like a resort to me.

i agree look on booking.com for hotel; simply use the filters to pick a place to your liking after reading the reviews posted;

If you need suggestions on lodgings in Monterosso, have a look at this list.....

http://rebuildmonterosso.com/visitors-information/

My wife and I stayed at a small place in Monterosso al Mare. It was within easy walking distance of the train station. We chose Monterosso as we did a day trip to Pisa and trains were convenient between the two points. At the end of our stay wedeparted Monterosso for Milan by train and didn't want to drag luggage around any more than necessary. If you're interested send me a PM and I'll look for the name and contact of where we stayed.