Even a -9°C low for an 8S string is 396.8Voc*34*.0035=47.2Vrise+396.8=444V. You have to get past a -13°C low before you get above the rated limit. More than good enough if you've got a quality SCC, which should have a bit of leeway so you can hit the limit and it will work as expected, not blow up if the setup isn't perfect at the limit.