Temperatures...how critical are they??

I have been seeing a lot about the temps lately. I have seen preferred ranges from 70-82, 70-75, 65-75...
Just how critical ARE these #'s ? And why the large variation on ranges? I understand with your yeast and to start fermentation you want temps warmer so the yeast is 'healthy' and can do it's job. But in the real world, how close do you have to be in any given range. I live in a large old house w/hot water heating system. So in the winter things stay a little cooler (64 during the day, 58 at night) We have no AC, so in the summer we grin and bear the heat waves when they come (sure could use one NOW! )
So with the limited ability to have a 'controlled' environment, which I am sure is true for many winemakers, is there a general temp range of 'operability' and an 'optimal' and 'ideal' temp ranges? Are they different for different types of wine?
I know I asked a lot of ?? there, but I am trying to get knowledgeable on these types of issues.
As always...TIA
Brian

Its all about the yeast. Too low (<50F) yeast shuts off. Too high (>120) yeast is irreparably damaged. Just right (65 - 75 ish) and you're in business. The lower the temp the slower the fermentation. The high the temp the more vigorous. Different species of yeast prefer different temps but I believe we're not talking about significant temp differences.

Temperatures and wine. A question with MANY answers.

If you do some research into wine making, you see some recommendations that white grape wines be fermented on the cool side. I believe it keeps more of the aromatics in the wine. As I understand it, this is a poor idea for wine kits.

Different yeasts work best at different temperatures. Other wise you may experience some bad flavours from the yeast. However, that may be more of an issue with beer making than wine making.

Degassing a cool or cold liquid is not a great idea, CO2 loves cool beverages. Warm it up before degassing.

Some folks believe in cold stabilization. Some believe that wines clear better/faster at cool temperatures. Some clearing agents are reported not to work well at cool temperatures, although that may be a CO2 issue.

If you're making kits, read the instructions. Try to stay within those ranges.

If you're not making kits, I don't know the answer.

I primarily make kits, so other wines that I may try will have to suffer thru the temperatures that work for my kits.

Steve

I have found 2 places in my house that are great for fermenting
Now; so far I only make small batches, but I get a low 70's temp
On top of the refrigerator in the kitchen and on top of the upright freezer in the utility room. I use large stainless steel soup pots for primarys and 1 gallon glass bottles for secondaries all wrapped in thick old bath towels

Brian, there are no such things as too many questions. We all learn and benefit from others inquiries. Keep em coming.
Troy

Like CP said, whites and fruits benefit from cooler fermentation temps while reds are fine with much warmer temps. degassing should be done at around 75* to do a goo job of getting enough out for your wine to clear properly.