There are a couple of factors here.

1. How much do you actually sweat.
- How hard you're working
- What temperature you're working in.
- What you're wearing
- How much you're drinking
2. How much of that sweat evaporates.
- Environmental temperature and relative humidity
- Wind or fan speed
- What you're wearing

I used to get a big kick out of gym exersizing and being drenched with sweat; always checked around me to see if anyone noticed... usually not.