Cellphone/Mobile Scripts (XHTML Mobile 2.3 Certified)!

I’m running this on my site and having an issue with “yesterday’s high/low” temps. When the page first loads, the correct temps are there, as soon as the ajax update fires, the numbers go green and then change to NaN. The time of the high/low is correct and doesn’t change. Anyone have any ideas on what I’m missing? I’ve been looking for hours and can’t figure it out. www.rkb2.com/cell.php