Cold weather sealants

I may have some attic vent covers to install shortly. Temps here are zero give or take 20 degrees right now. What would be the best sealant to use on the screws to avoid water leaks given the wintry conditions? I was hoping to be able to brush away snow, melt/dry everything down and then install as usual. I just want to be sure that the sealant will cure at zero to 20 degrees or so (I will avoid below zero temps).

Eric Arnold (WCT) turned me on to DOW CWS. If you look it works way down below zero.

I buy from a contractor supply called smaller and company. Works great and love it for all around bat and bird work now.

http://www.dowcorning.com/content/urethane/cws_product_page.asp

Used to always buy whatever I could get at Home Depot or Lowes but stopped doing that after finding this.

Best,

Justin

Thanks. Looks good, I'll try some. Any others>

Will try the CWS in the future. Looks like good stuff. Going to use Lexel for this one as it is locally available and I have to do this one tomorrow.