Fret Squeak

I'm new to Ukulele and am having an issue when i change chords, specifically the C string on the second fret, when I change from a G chord to a C or F chord. The string will sometimes squeak as I release the chord and move to the next chord. It isn't a problem when I'm playing slowly and easy, but is an issue while playing fast and hard. I am pretty good at fingering the note between the frets, so I believe my technique is good.

I can duplicate it by slowly raising my finger on the C string. When I do so the string will buzz on the top of the fret.

I don't see a flaw with the ukulele, but maybe there is something I'm unaware. Suggestions?

I'm not sure, but it sounds like you may be experiencing fret buzz and not string squeaking.

Fret buzz comes from a string contacting a fret other than the place you are fretting with your left hand. The string will vibrate against the fret and make a buzzing sound. This is due to a low string height or a high fret or aggressive strumming or plucking.

I have never experienced fret squeak with my left hand. I have however experienced a squeak with my right hand playing finger style. The sound comes from the mere contact of my right hand fingers with the strings. Acquila strings are the squeakiest strings I have used. I don't have a problem with squeakiness if I use fluorocarbon strings.

Keep practicing! Sounds like your hands aren't quite synced up and you are trying to make sound with the strings while your fretting hand is still moving between chords. Two approaches: switch chords faster or play the song slower. I'm always going to recommend #2. By going slower you'll have time to practice precise changes and be building positive chording habits.

Also keep in mind that the harder you play, the more the string moves and the harder you have to press down to make the string keep contact with the fret. Don't waste energy by pressing too hard, but don't be surprised if you hear more noise and buzzes at first when you go all-out with your strumming. It's all a balancing act...

Could be an issue with the action as Bikemech says, but from my own experience learning, I think Brad nailed it and the problem is that you are still touching the string while it's no longer (or not yet) properly fretted. If that is the cause, the skin on your fingertips becoming more taunt (or developing calluses in some cases) will also help with the strings not "sticking" to the skin.