When a stock's share price is lower than the mercury in a North Dakota thermometer in February, investors tend to give it the cold shoulder. But as the market warms to a stock's prospects, its price can heat up in a hurry. Alas, you can rarely tell that a stock is melting investors' hearts until after it has made that move up.

Taking the market's temperature
But Motley Fool CAPS' proprietary ratings, aggregated from the opinions and accuracy of 170,000-plus members, offer a great way to monitor investor sentiment. Following a CAPS rating trend can help us determine the best time to invest. Let's look at previously rated one- or two-star companies that have recently enjoyed a bump in investor confidence and see whether they're truly heating up -- or headed back to the deep freeze.

Company

CAPS Rating 
(out of 5)

Recent Price

EPS Estimates (This Year - Next Year)

Atmel (Nasdaq: ATML) *** $11.47 $0.42 - $0.64
PolyMet Mining (NYSE: PLM) *** $2.09 NA - NA
Universal Travel Group (NYSE: UTA) *** $6.19 $1.38 - $1.51

Source: Motley Fool CAPS; NA = not available.

Obviously, this is not a list of stocks to buy -- just a starting point for further research. Yet if some of the best investing minds are taking notice of these stocks, maybe we should, too. 

Caution: Contents may be hot
Whenever a new gadget debuts on the market, the geek squads spring into action and break down its components to see who had their technology included, and the competition to get a piece of the hottest gadgets is fierce.

The ubiquity of touchscreens, particularly in the latest smartphone iteration, means that Atmel and Cypress Semiconductor (NYSE: CY) often find themselves at loggerheads. Where Cypress has Research In Motion's (Nasdaq: RIMM) BlackBerry locked up, Atmel is on the iPhone. Yet both have impressive client lists, and for investors, maybe it's not an either-or proposition, but rather a basket of winners to collect.

That's not to say each side doesn't have its partisans, and if you ask CAPS member rdwolf34, Atmel is the leader.

In addition, Atmel does a good amount of business in Asia 50% (currently lists 31% Europe, 19% Americas). I like the heavy exposure in ASIA for the huge growth potential in computer products Atmel could have their chips in.

There have been recent reports Atmel will be moving from NVM (Non Volatile Mem.) 24%, RF/Auto 12%, ASICs: 24%, MCU: 40% to all MCU. I think this is a good move and will help Atmel take advantage of Smartphone and Tablet and other touchscreen embedded products.

Let us know in the comments section below or on the Atmel CAPS page whether it or Cypress -- or Synaptics, which basically created this business -- still has the touch.

A clear road ahead
Because of its myriad business uses, copper prices are often subject to the vagaries of the economy. Both the Philadelphia and the Dallas Fed reports showed significant improvements in regional growth, so the November jobs report, with its plunge in employment in manufacturing and retail, was disappointing.

So far, though, copper prices have held firm at around $4 per pound, primarily because the dollar weakened on the economic numbers. That psychologically important threshold is key for copper miners like Freeport-McMoRan (NYSE: FCX), but also for PolyMet Mining because it sits on one of the world's largest undeveloped deposits of copper, nickel, and other non-ferrous metals.

The risk for investors, though, is that PolyMet is only an exploration/development-stage company and hasn't extracted an ounce of any metal. The permitting process is complicated and has generated a lot of political opposition. However, CAPS member circa1973 says that despite the hurdles, the miner will win out.

Eventually this mine will open. Yes it will. There are several ore bodies in the same area that will be tapped due to global demand. I have been on the [PolyMet] site and see the existing infrastructure they plan to use from the old LTV Steel mine. Lots of work to do, but still a good money saving plan.

Only you can decide whether PolyMet belongs in your portfolio, so add it your watchlist and have all the Foolish news and analysis about the stock gathered in one place.

Golden globe
Chinese online travel agent Universal Travel Group has been trying to tap into the success that priceline.com (Nasdaq: PCLN) has found in booking travel in Asia, but faces a blogger questioning the veracity of its financial statements. It's something we've grown accustomed to these days, and it has weighed on the company's stock price.

Out of sight, out of mind, though, because we haven't heard much out of the travel agent other than its third-quarter results, which seemed to show higher revenues and profits. Assuming the numbers can be trusted, 94% of the CAPS members rating Universal Travel Group think it will outperform the broad market averages. Head over to the company's CAPS page and let us know what you think.

Checking the mercury
Are these stocks invitingly warm or bitterly frosty? It pays to start your research on Motley Fool CAPS. Read a company's financial reports, scrutinize key data and charts, and examine the comments your fellow investors have made, all from a stock's CAPS page. Then weigh in with your own thoughts on which stocks you think are hot numbers and which offer cold comfort. It's free to sign up.

Apple and priceline.com are Motley Fool Stock Advisor picks. The Fool owns shares of Apple. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. 

Fool contributor Rich Duprey does not have a financial position in any of the stocks mentioned in this article. You can see his holdings. The Motley Fool has a disclosure policy.