The official height of the playable character in the game is currently unknown. We were able to get the estimated character height of the playable character by using rough scaling observations of his perspective in the gameplay.
This height analysis needs to be considered as a rough height estimate for the character featured in the game. The game’s mystical/fiction nature makes it very hard for us to make a proper point of reference in calculating the character heights ingame, nevertheless, we should still be able to make an estimate based on some observations available on the gameplay.
By observing the character through his perspective in this Youtube Gameplay Video (We Were Here Forever [PC] Full Gameplay Playthrough No Commentary), we are able to give the character an estimated average height of around 5 feet and 8 inches (172.72cm). This estimate was done by observing the scale difference between the character and a light brazier in the game. The frame of reference can be found at time frame [2:32:13] in the video.
By observing several images on Wikipedia, we are able to create a visual estimated height of the brazier similar to the one in the game. The cauldron like brazier appears to stand at around the height of 80 to 100cm. Since the brazier stands at around the pelvic height of the character, it gives out an idea that the main character is somewhere around 165 to 177cm. This estimate was further visually observed using Hikaku Sitatter Height Comparison Tool.
Considering the fictional and rather mythical theme in the game, this estimate needs to be considered as a rough scaling estimate and is therefore subject to future changes when the official height data rolls out.
Hikaku Sitatter Height Comparison Tool
Youtube Gameplay Video (We Were Here Forever [PC] Full Gameplay Playthrough No Commentary)