If your outdoor space is visible to neighbors, nudity is not acceptable out of respect for those around you.
On Bodily Needs
Out of politeness and consideration for others, you should avoid peeing in the open ocean and use the nearest proper lavatory instead.
Maintaining personal hygiene with deodorant is an essential sign of self-respect and basic consideration for colleagues and social contacts.
If necessary, tell the person privately and kindly, preferably toward the end of the day, giving them a polite way out of the conversation.
It is entirely acceptable to decline a physical greeting due to heat, and using light humor or a high five can keep the moment comfortable.
Avoid asking absolute strangers for sunscreen unless you have established a brief rapport or find yourself in an urgent, painful burning situation.
Hinting heavily by applying your own lotion and offering to share is polite, but directly policing a stranger's sun safety is best avoided.
This is an intimate act that should be reserved exclusively for individuals you already know very well.
The Social Contract
Constant complaints about hot weather can become tedious, making it better to take a break from venting about the climate socially.
Discreet electric or hand fans are acceptable if they don't crowd others, though noise-producing fans should be turned off once a theater performance begins.
Loud garden conversations or music should ideally wrap up by 9pm if you have close neighbors, and children should remain quiet before 8am on weekends.