I guess gloves with open finger holes may keep the hand somewhat warm.  The friction of playing would have to do the rest for the fingertips.  Or perhaps some single malt.

No doubt because of my part-Sicilian DNA and always living in humid climes, I've never had this problem:  Maybe it's the olive oil and garlic intake . . . . . . . I'd loved to have been cold on an outdoor gig, I seemed to only do outdoors is summer, where cold was NOT the problem.
 
I always wondered why I could never get a sharp attack with my fingers (more pick-sounding) and other guys could.  Then I read one of Bob Taylor's articles where in the course of talking about the variables involved in tone, he mentioned 'bone tone' that they certainly couldn't account for when voicing their guitars:  Some people just have bonier or fatter fingers, and this made the difference.  They just had no way to account for the individual physiognomy of individuals' fingers.  No wonder this guy has made such an impact in acoustic guitars.
 
J o e y

So Hendrix wasn't really playing with his teeth. He was actually rubbing his nose on the strings!
 
hehehehe
 
Bill, tgo

It's an interesting observation (though as Bill alluded to, physiognomy might not be the word you were looking for), and it does make sense that finger anatomy would make a contribution to tone.

I've never tried it, but I can't see where putting single malt on your fingerboard would help.

I use Jack Daniels all the time.  (Works great!)

Had an open air festival gig on Sunday afternoon firstly I tried the thing I'd done before which is to wipe my fingers on my jeans to dry them off and that worked well but I had to keep doing it to have any  consistency. The nose grease worked the best I'd say and kept my fingers doing what they are supposed to be doing best however I'd be a bit concerned about losing the brightness if It was going to be a regular part of my playing. But It's gonna have to be a work in progress till i find the right balance.
Jazzyvee

Jazzy - I think your recent technique is a good one.  As far as losing brightness over time, have you tried using something like BassBrites after a gig?  www.bassbrites.com
 
I use them and they work great.  I guess a number of substances that do the same thing would work, but these are pretty convenient and fit in a bag or case really easily.  They aren't incredibly cheap - about $10 USD, but the convenience factor outweighed the cost.  I use Rotosound PSD's and the windings on those strings are larger (to me) than a traditional roundwound string, so junk (oil, etc.) gets caught up in the grooves more easily.

I decided to try the Jack Daniels trick.  I drank 1 shot and it didn't seem to make much difference.  However, after 3 shots I definitely noticed a difference: my fingers felt much more relaxed on the strings and I was not only hitting the notes I MEANT to play but several additional notes as well.  After 5 shots there was absolutely no issues with finger grippage... all was well with the world. At about the 8 shot mark I noticed that I felt no friction at all between my fingers and the strings... it was then that I realised I had forgotten to strap-on my bass.  At 10 shots a new lubricant entered the equation and the experiment came to an end.

Jazzyvee, I have experienced this same thing on several occasions even playing indoor gigs. It feels almost like the top layer of skin has worn away & the new skin underneath is sticky. It's very frustrating because it definitely affects your timing. I try switching fingers & using my ring & pinky fingers to pick with until I can wash my hands to get rid of the sticky feeling on my index & middle fingers.  
 
I never thought about the nose oil trick, I will try that next time! My next gig is outdoors next week, so chances are that I will need it!
 
Stout71, I had never heard of Bassbrights before. I just ordered some, so thanks for the tip!

Jazzyvee, Jerry is right about Bass Brites! I just got some & it not only cleans your strings & makes them sound brighter, but it also puts a coating on them that feels like silicone, but it's not oily or wet feeling like Finger Ease. I think this stuff will eliminate the sticky finger syndrome especially if you clean your strings before & after you play. After to get the gunk off & before to put the coating on them to make your fingers slide easy. I got my Bass Brites less than a week after ordering them.

For us Eiropeans they have to be ordered through bass strings online .  I got as far as checkout to find shipping to the UK would be $11.50 for 2 packs plus the $23 for the product.  (in case anyone is planning on buying some).
 
graeme

I just used the Bass Brites at an outdoor gig & they work great! I could feel my fingers getting sticky during the soundcheck so I cleaned the strings with Bass Brites & the coating works like a charm! No more sticky fingers! Plus my strings still sound like new after 2 gigs on them with the last being outdoors on the water with 85 - 90 degree temps & 90% humidity, so I was sweating a lot which would have normally killed the new string sound. Honestly, I would buy Bass Brites for the lubrication factor, the fact that they also keep your strings sounding bright longer is a bonus! I can clean all 4 strings with 1 cloth & each tub comes with 30 cloths so they should last a good long time. I bought 2 tubs & they were less than a new set of strings even with shipping, so I think it is a good value.