Best Time to Visit Prague- want to avoid high season

Was there the last weekend in January in 2008 and it was crowded then, so good luck.

We visited Prague arriving late February 2012 before going in to Germany, then a night early March before departing. Those time periods are the Green Garland Very Low Season. I recommend the Green Garland as long as you can ascend without an elevator. It's a short walk to the Clock and the Bridge. Breakfast is "continental" but very good and much more substantial than a French style "continental".

For Pension U Zeleného vence/Green Garland Pension season dates and rates: http://www.uzv.cz/room-rates-services/

Low Season = Jan 7 to March 27 + month of November

Middle Season = Jan 1 - 6, April 3 - 15, July and August, Dec 1 - 22

Prague is busy all the year round, I visit at various times of the year and can't really say when would be the quietest or lower rates.I stay out of the main city centre as I get better rates and I prefer staying in Pargue 6 area, and I have found that I have had cheaper hotels in August than in May,I have no explanation for why.
New year was very busy and August was crazy busy but there is no real down time in Prague especially if visiting all the main tourist sites.
avoid August to avoid the busiest time but as far as prices go ,book early and search for any deals you can.

My only advice is to review ALL Unclegus' posts on Prague. We found his comments/recommendations to be very helpful for a week stay in Sept. 2017. If we ever go back, we want to coordinate with Unclegus' frequent visits so we can treat him to a well-deserved dinner at one of his favorite hang-outs. He's a RS Forum Rock Star.

Thanks very much RCA I will take you up on the offer if you come back to Prague.
Yes I have been travelling to the Czech republic since 1993,went to Prague on a day trip and just felt I was home. Since 2002 I have been making at least one trip a year but for the last 5 years or so been making at least 3 trips a year mainly due to Low cost carriers operating from my home airport and the fact that I get a lot of paid leave, as I head towards retirement I hope to spend longer periods in the country.
Over the years I have made some great friend through various travel forums and since joining Rick Steves have made a few more.
I try to be honest as I can in the posts I make about Prague but realise that it is very much my opinion that I give and not everyone is like me ( thanks goodness). Cities like Prague like all cities are dynamic and are constantly changing it is impossible to keep up with changes but I do try to keep up with the changes with the Beer Scene in the city ( my specialist subject) and do spend time visiting new pubs and especially micro-breweries.
Also because I am such a regular visitor and use the public transport system a lot I do know how to get round the city and to outlying areas but even at that there are always changes going on, upgrading, change of routes and repairs ,I do try my best to work out what is going on but it is not always easy.
I was last in Prague over new year where I met up with and went on a walk with a Rick Steves member and her husband , most enjoyable too.
I will be back in Prague sometime in April with a friend from Kansas City I met at a beer Festival in Prague many years ago ( his son used to live and work in Prgaue), actually he and his family have become great friends and they are visiting Edinburgh next week to help celebrate my younger brothers 60th birthday ( yes I am that old).
I also hope to be in Prague over the summer with a couple of friends from my walking group, summer time in Prague and indeed the whole of the Czech republic is great as they country really embraces the outdoor life in the warmer weather, great places for going for a walk with a fantastic public transport system to get you to loads of areas and wherever you go there is always a place you can get a beer and a bite to eat.
yes I love Prague and the Czech Republic.

The best time is later October (still opened gardens), November and February. They are less people. Good luck!

We went to Prague with my friend in February 2014, and it was ok. Well, major sites are still crowded, but we didn't have any difficulties booking a hostel and moving around the city. Well, that was four years ago, so things might have changed a bit now, but different sources like waitamoment , rove.me , and some local websites—all claim that November–February are least crowded months. But consider that then the day is shorter, so you can't enjoy walking and taking pictures for so long + the outdoor experiences are not as enjoyable.

Honestly, Jan - March (pre-Easter) is a great time to avoid the crowds -- you won't avoid all crowds the whole time though unless you completely avoid Charles Bridge or Old Town Square. In the autumn, I would recommend November (pre-Christmas market opening). Other than that, it's all pretty much the same!