Not OP, but there isn't really a practical temperature for that. Giardia cysts (beaver fever) and e. coli can survive temps up to 60-70 degrees Celsius. And at that temp you aren't going for a swim without cooking yourself.
Most things aren't as active in the winter. I believe leeches more or less "hibernate" in the mud during winter, and algae blooms definitely aren't a problem. So you wouldn't have to be as concerned with gross things, depending on what you're trying to avoid.
thisismyfirstday t1_j62gezb wrote
Reply to comment by Wats_Taters_Precious in We are Canadian scientists using new techniques to transform how we monitor and protect our freshwater lakes. Ask us anything… by iisd_ela
Not OP, but there isn't really a practical temperature for that. Giardia cysts (beaver fever) and e. coli can survive temps up to 60-70 degrees Celsius. And at that temp you aren't going for a swim without cooking yourself.
Most things aren't as active in the winter. I believe leeches more or less "hibernate" in the mud during winter, and algae blooms definitely aren't a problem. So you wouldn't have to be as concerned with gross things, depending on what you're trying to avoid.