What's my fermentation temp?

I am trying to keep 5 gal. of EdWort's hefe down to temp, quick question.
I made a small swamp cooler and my carboy has one of those sticky fermometer temperature gauges stuck to it, above the water line.
It is reading 68 degrees right now, my ideal temp.
Is that the actual temperature? This is the beers first day of vigorous fermentation, I've heard the temp of the beer is actually slightly higher, around four degrees higher.

Fermentation temp is usually a few degrees higher than the ambient air temp. The stick on thermometers are usually closer to the temp of the contents, so long as they're stuck below the level you're filled to.

Submerged the carboy so sticky is below water line, the adhesive on those things is impressive, never had one fall off yet even with constant washes.
Thanks Chshre

I agree, the stick on thermometer should be pretty accurate. The adhesive is impressive, but I noticed that prolonged contact with water does seem to jack up those stick on thermometers; I've taken to putting some clear tape over them to try to keep water from getting underneath. The first one I did in a water bath (without the cover tape) is hard to read now, there are white squares under every number now and the indicator coloring is washed out.

Enjoy the hefe, I've made 3 batches of Ed's recipe and it's really good.

Clear tape installed now.
I hope it is good, the wort tasted delicious! I took a small bit and caramelized it on the stove, made some great bratwursts. Bavarian Style!