Don’t know if the weather is going to be hot or cold during Bike Week. Last week here in Sarasota the temperature was in the low 80’s but now it is in the low 70’s (daytime). Best to be prepared for the cold. I found a couple of sites online offering hand warmers for sale.
The manufacturer has a site, Grabber, where you can buy them direct. They will have the freshest product. I’ve read in some reviews that they won’t work if they are old, and some stores could have a stock sitting on a shelf for a year.
Campmor has them. And there is another camping supplier, REI.