Temperatures are starting to heat up, and so are some of stocks that were cooling down after rallying earlier this year. Shares of Datadog (DDOG 3.58%), Bumble (BMBL -1.55%), and Zoom (ZM 3.49%) are some of the stocks making what should be sustainable moves right now.

Datadog, Bumble, and Zoom are all down at least 20% from their recent highs. Is this opportunity knocking for risk-tolerant growth investors? Let's go over why I believe these are three names that could heat up your portfolio this summer.  

Friends gathering at a summer cookout.

Image source: Getty Images.

1. Datadog 

Cloud-computing stocks have been gray since peaking in February, but the skies are finally starting to clear. Datadog runs a monitoring and security platform for cloud applications, offering essential services to enterprises needing real-time visibility into uptime reports, analytics, and a growing number of features that Datadog keeps adding to beef up its ecosystem.

Business is booming. The number of large clients on pace to spend at least $100,000 a year with Datadog has climbed 50% over the past year. When you're on the Datadog platform you tend to stick around, lean on it more, and add new Datadog modules. Dollar-based net retention rate has clocked in above 130% for 15 consecutive quarters. In other words, existing customers are spending on average 30% more through Datadog than they were a year earlier. 

Revenue growth has slowed over the years, decelerating to a still-impressive 51% year-over-year gain in its latest report. It was another "beat and raise" report. Datadog sees growth of 51% to 52% in the current quarter, and since it's historically been conservative with its crystal ball, it's fair to say that growth is accelerating again. 

2. Bumble

Online dating slowed during the pandemic, but there aren't too many better plays for the reopening of the planet than Bumble. It operates two of four highest-grossing online dating apps in the world in its namesake app (second only in popularity to Tinder) and Badoo.

To be fair, Bumble didn't see its business shrink during the COVID-19 crisis. Revenue still rose 19% in 2020. However, with revenue climbing 31% in the fourth quarter of last year and 43% in its latest financial update momentum is clearly on the side of the bulls. 

The appeal to Bumble's rise is that it only lets women initiate contact with a prospective match. The app was started by a Tinder co-founder that had a better mousetrap, and it's paying off so far in 2021. Revenue at Baidu rose 61%, now accounting for two-thirds of the revenue mix. 

Investors haven't had a lot of time to warm up to Bumble. It hit the market at $43 four months ago, nearly doubling on its second day of trading before giving all of those gains back in the following weeks. You can get in now for just a little more than what IPO investors paid, and that should make your heart skip a beat.

3. Zoom

A little more than a year ago, we were all downloading Zoom as a way to stay connected with workmates, classmates, friends, and family. Zoom has been sliding as an investment since October when viable pandemic-tackling vaccines were inching closer to reality, but Zoom keeps growing.

Classrooms, businesses, and family reunions have returned to in-person gatherings, but we're still keeping Zoom active for situations when it's more convenient. Revenue keeps trouncing expectations, and Zoom is checking in with some ridiculous profit margins. 

Zoom's revenue nearly tripled in its latest fiscal quarter, and the bottom line is growing even faster. Zoom's net profit margin is at a whopping 24%. Zoom's continuing ascent as a business and the stock's slide has rattled the multiples. Zoom was trading for 126 times trailing revenue at its peak in the fall of last year. Now it's fetching just 77 times this year's expected earnings. Yes, earnings. You didn't delete the Zoom app. The market was wrong to delete Zoom, and now it's starting to heat up again.