Depends on how big your pile is and how much work you want to do. I tend to make my piles pretty large, and though it's backbreaking work, I only use a pitchfork and a rake hoe to mix things around

As long as the C:N ratio is in the range, and there is enough high carbon material to munch on after turning, your bacteria will continue working and generating some heat as they do. Your air temperatures influence what goes on in the compost pile only a little and then that most often is related to the amount of moisture in the mix.
I find that bacterial activity in my 4 x 4 x 4 compost piles will only slow down when the air temperatures are below the 20 degree point for quite some time.

Yes, i plan to make this pile pretty large, actually it's already pretty good sized, and it seems like i can't get enough greens to keep it hot, which is wierd cuz i've been getting a lot of kitchen scraps etc. but, i plan on going to my friends farm to get some cow manure, that oughta take care of things nicely.

I'm sure someone will correct me if I'm wrong, but your pile won't stay continuously hot (in the 104 to 150 range). However, you can have your compost go through many hot cycles by adding new material and turning.

The temp has to do with the type of bacteria in the microherd that are doing the work, and they work in cycles.

Mesophilic bacteria start the job, then when the compost gets over 100 degrees the thermophilic bacteria get to work. Thermophilic bacteria work fast, then the compost cools off and the mesophilic bacteria get to work again.

That's how I understand it, anyway.

Here is a link that might be useful: Compost Bacteria

If you have trouble with nitrogen/green sources, I always say, when in doubt pee on it lol. I usually have trouble finding carbon sources rather than green sources

If you suspect not enough nitrogen and the pile is dry, just use the famous 'liquid gold' a.k.a urine :P
(Beware of salt content of urine though)

However, depending on the look and feel of your compost, it may be just completely natural and fine for the temps to drop.

If it's all chunky and cold, then you have a problem.
If it's loamy and cold, then you don't have a problem.

It has to be airy as well since they need oxygen... Anything that can jab into the pile works.

I use my hand (with a pair of latex gloves), some worn chopsticks and a spade to turn my tiny compost bin. sometimes it's so hot it stings my fingers.

oh but yes, it gets PLENTY of liquid gold.... maybe i just need to give it more time.

that's what i'm going for: so hot it stings.

The tool I find most useful for turning my compost is a hay fork, maybe called a pitchfork by some. It isn't as heavy as a garden fork and has 5 tines so I can stir and "fluff" my compost quite nicely. I know they can break if used on heavy soil but on lighter compost it works well.

I have a compost fork, and a 18" compost thermometer, and recommend both.

The thermometer tells you when you need the fork to turn the pile. I find a 4' diameter mesh bin made of 1/4" hardware cloth works great. I buy either 18" or 24" high hardware cloth works fine; the dirt below stores heat so you really don't need a 3'x3'x3' bin.

For my larger bin I have a door at the bottom. So I simply dig from the bottom and pour it on top at times that it needs a good mixing. My other bin which is a 55 gallon drum I use a 2 1/2 foot bulb planter that attaches to my drill. It works great at keeping things fluffed when needed. I us it on my large bin also at times. I think this does a good job at polking wholes in the piles letting air get back to everything with out disturbing the whole pile.