When a stock's share price is lower than 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's made that upward leap.

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)

Best Buy (NYSE: BBY)

***

$34.00

$3.31-$3.61

Cray (Nasdaq: CRAY)

***

$7.47

$0.22-$0.40

F5 Networks (Nasdaq: FFIV)

***

$108.38

$2.84-$3.55

Source: Motley Fool CAPS.

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
Although e-commerce spending jumping 12% from the year-ago period in November and December as consumers shopped via their computer keyboards instead of hitting the bricks-and-mortar operations, that wasn't enough to mollify investors who sold down Amazon.com's (Nasdaq: AMZN) stock the other day because they said first-quarter operating profits would fall. comScore said online shopping hit a record of $32.6 billion this past holiday season as Cyber Monday saw a 16% year-over-year jump in spending, breaking through the $1 billion threshold for the first time ever.

Those kinds of numbers were what sent electronics superstore Best Buy tumbling in December after it said its bet on a new big-screen TV upgrade cycle was flatter than the 3-D and Internet-ready TV screens it was trying to sell. RadioShack also ran into static as a result.

Yet while All-Star CAPS member SlothropsMonkey ultimately sees Amazon as the better bet in the battle against Best Buy, Sparticus501 says the market's reaction to the news is overdone and the electronics retailer's new, lower price is a bargain:

This stock is too cheap. Consumers may like to order things online, but most still want to go and physically touch and see what they are buying, especially electronics. BBY is set to dominate this market, with the cheapest prices and the widest selection of all sorts of hands on products. There biggest competitor, Circuit City, is gone. This stock will make money over the next two years.

Not your father's abacus
Supercomputer maker Cray is rising in the estimation of CAPS members who like its forecast of profitability for 2010 and the expectation that 2011 will be just as good. While China has surpassed U.S. companies in producing the fastest supercomputers, taking the No. 1 slot of the top 100 fastest for the first time ever, Seattle-based Cray is still doing a brisk business (well, "brisk" for supercomputers anyway). It has two of its new XE6 behemoths shipping later this year indicating the sales and profits forecast it issued will be backweighted to the second half of the year.

Although the XE6, which is powered by Opteron processors from Advanced Micro Devices (NYSE: AMD), is the highlight of its supercomputer portfolio, it continues to sell a number of its midrange computers, too, like the XT6, that are also run with Opteron cores, 1,248 of them in fact.

Price per gigaflop is falling (a gigaflop is a billion float-point operations per second ... sounds fast) making these midrange computers much more accessible to a wider range of customers. There are only so many high-end supercomputers Cray or even rival IBM (NYSE: IBM) can sell, so this downward pressure on prices could open up more doors for Cray.

Of the 139 CAPS members who have rated the supercomputer maker, 83% of them believe it will go on to outperform the broad market averages. Let us know on the Cray CAPS page if this investing opportunity still computes.

Step into the stream
Earnings were also the cause of F5 Network's tumble this month, despite the fact the results looked pretty good: revenues were at record levels, non-GAAP earnings doubled, and cash flows were strong. That's all part and parcel of the reason Fool Tim Beyers sees the market as underestimating the potential of this Internet backbone equipment supplier.

While there is some sense to the argument that F5, Rackspace, and Riverbed Technology (Nasdaq: RVBD) were floating along on a bubble about the benefits of cloud computing, now that it has seemingly burst and valuations in the space are much lower than they were F5 could be a good play here. Riverbed's bounced back up from its sympathy fall as has Rackspace. That leaves F5 odd man out and leaving CAPS member kpoeppel suggesting the froth has been skimmed off the top: "Stock price was slaughtered as the short-term speculators jumped ship. Still a strong growth stock, without the speculative excess."

Checking the mercury
Are these stocks invitingly warm or bitterly frosty? It pays to start your research on these stocks 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 little numbers, and which offer cold comfort. It's free to sign up.

Best Buy is a Motley Fool Inside Value selection. Rackspace is a Motley Fool Rule Breakers recommendation. Amazon.com and Best Buy are Motley Fool Stock Advisor picks. The Fool owns shares of Best Buy, and International Business Machines. 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 owns shares of Best Buy but does not have a financial position in any of the other stocks mentioned in this article. You can see his holdings here. The Motley Fool has a disclosure policy.