It depends upon the brand. Most that say tropical lines need to be used in fairly warm conditions and that includes both air temperatures and water temperatures. I took a tropical line redfishing south of New Orleans a few years ago. They had abnormally cold weather for December while we were there and the line was truly useless. It was like trying to cast some heavy telephone cable. Thankfully, I had brought an extra line along that was better suited to the weather and got by. Many times the website or catalog for a line company will show you a temperature range for lines specifically called tropical or coldwater.
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