I've dragged on cool days (50 degrees in the early morning) and it certainly isn't as good as when the track is hot. Drag radials seem tricky. If enough guys go ahead of you and heat up the launch pad and you get a serious burnout you should do OK. The cool air will help the HP so maybe that counters it a bit but you won't get your best times without good 60' times. I got around 1.9 seconds if I recall on cool, damp days but that meant pretty much roasting my tires off and bogging down a little on the launch so I didn't get too much tire spin. The bog ends up slowing down your 1000' times but the 60' time is so important that it seemed like a reasonable trade off.
The bottom line is lower horsepower cars will do better relative to you because they don't have the potential wheel spin you will have. For example, a friend of mine with a Cobra kit car was getting 8.4 second 1/8th mile times regardless of weather because his car was so light and he just went WOT from the launch. I couldn't do that and he would consistently blow me away at the 60' point. However, I would catch him just before the 1/8th mile and blow his doors off by the 1/4. But under better conditions I would have been even at the 60', killed him by the 1/8th (7.7 or so vs. his 8.4) and left him in the dust by the end of the quarter. The moral of the story is if you are racing a lighter, lower HP car, you won't do as well against him if the track conditions are as you describe.