Although it may be unexpected, one of the most prominent hazards that affect beach volleyball is heat/the sun, which can hinder play in a number of ways. Firstly, sun rays can reduce a player's vision, as bright sun makes it more difficult to look up and around at your surroundings (fun fact: there is a type of serve that is only used in beach volleyball called the "sky ball serve" that utilizes the sun's brightness through underhand serving the ball incredibly high, which makes it so the opposing team cannot see where the ball is coming from). 

Secondly, the sun can scorch players feet. As the sand heats quickly and is capable of reaching very high temperature, it can become painful to even step on sand, let alone play volleyball on it. Players may blister their feet or potentially be afflicted with serious burns. 

Finally, it is also much easier to get exhausted the hotter it is. Not only are you losing water from sweating playing volleyball and being physical active, you are also losing water from sweating due to evaporative cooling. These two methods of water loss can lead to a player collapsing from exhaustion or heat stroke if it is incredibly hot. All these factors combined make the sun an important variable to consider when deciding whether or not to play beach volleyball! 

Source