During Flower what is the lowest temp allowed for ...

Give them whatever your best is. They will survive. I let my tent drop down to 15c-18c at night from 26c during the day. converted units. 59f-64.4night 78.8 day If it gets to cold you might notice the leaves/stems blushing with purple on them and some of them may get a bit yellow as well. Growth can be stunted but nothing to bad if its around 18c/64f, more so when it gets real low 10c/50f or below. Best of Luck and Happy Growing!

What they can stand and what you should shoot for are too different things but I try to never let anything go much below 60F.. but in nature they get way colder nights than that obviously.. Depends on day time temps too.. you don’t want massive swings from lights on to lights off.

Ideally not more than 10° difference from night to day for best growth and 76° is ideal for lights on, so I don't like them to go past 66° at lights out.

You can go to 25F before the plants will start to die. In your tent I wouldn't go below 55F.