Peter, a difficult one to answer. I have a permanent catheter so notice how much urine I produce, overnight I sometimes produce as little as 200mls sometimes it can be 1800 mls. Same in the day sometimes I can produce 500mls an hour sometimes 50mls an hour.
The warmer weather will soon start to affect urine out put. Other drinks, tea, coffee etc will also affect output in different way to water.
Hopefully someone else will be along to help
Thanks Chris