The stock market doesn't rise and fall according to the seasons. But it almost seems to be doing so lately. After a sizzling summer in 2018, stocks began dropping in the fall and early winter months. Now that spring is almost here, the stock market is close to its levels from August and September.

There's no way to know for sure how the market will perform going forward. However, there are stocks that you can buy that appear to be great picks. In particular, Square (SQ 0.14%), Teladoc Health (TDOC 0.35%), and Vertex Pharmaceuticals (VRTX -0.86%) look attractive. Here's why these are three hot stocks to buy in March.

Three light bulb images formed by jigsaw puzzle pieces with a finger pointing to one of them.

Image source: Getty Images.

1. Square

Square hasn't yet regained its highs of last year, but the payment applications stock is still up nearly 70% over the last 12 months and almost 40% so far in 2019. Although the stock might seem ridiculously expensive, with shares trading at close to 70 times expected earnings, I think that Square has a lot of growth potential.

The company should have a significant growth opportunity by just penetrating more of the U.S. payments market for small to medium-sized businesses. However, the global opportunity could be five times greater than the U.S. market.

Square started out with its credit card devices but now provides an ecosystem of products and services. This expanding ecosystem provides even more ways for the company to grow. For example, Square thinks that the market opportunity for its e-commerce and software applications is around $18 billion. That's more than five times the company's total revenue over the last 12 months.

Newer products open up more avenues for growth. Square's free business debit card for businesses, the Square Card, enables the company to collect interchange fees. It's likely that Square will move more into the banking services arena, with the company recently reapplying for a bank charter.

Check out the latest earnings call transcripts for Square, Teladoc, and Vertex.

2. Teladoc Health

Teladoc Health is another stock that swooned in the fall but is rebounding nicely. The telehealth services provider's share price is up more than 55% over the last 12 months and has jumped over 30% year to date in 2019.

The investing thesis for Teladoc Health appears to be rock solid. Healthcare costs are rising. Payers, including government programs, insurers, and employers, are looking for ways to control these rising costs. Telehealth provides a great alternative for helping keep healthcare costs under control. And Teladoc Health is the clear leader in telehealth.

The company already has more than 12,000 customers in over 125 countries. Around 40% of the Fortune 500 companies use Teladoc Health's services. Teladoc offers a broader array of telehealth services across more of the world than anyone else.

Teladoc's growth has been phenomenal -- 59% year-over-year revenue growth in the fourth quarter of 2018 and 75% annually over the last five years. The company should be able to continue delivering strong growth for a long time to come, with aging demographic trends across the world driving higher demand for telehealth services.

3. Vertex Pharmaceuticals

Vertex Pharmaceuticals hasn't soared as much recently as Square or Teladoc Health. But the biotech stock is up more than 160% since early 2017 and has multiple paths for even more growth on the way. I think that Vertex's growth prospects arguably make it the best biotech stock on the market right now.

The first path for Vertex to grow is to simply reach the total addressable market for its already-approved cystic fibrosis (CF) drugs Kalydeco, Orkambi, and Symdeko. Around 18,000 CF patients currently use one of Vertex's drugs, but there are 39,000 patients that could potentially be helped by the therapies.

Another way for Vertex to grow is by winning regulatory approvals for additional indications for its current drugs and for new CF drugs. The biotech should be in great shape to do so. Vertex plans to submit for approvals of a new triple-drug combo by mid-2019. The company thinks that its triple-drug therapy and expanding indications for its current three drugs should increase the addressable CF patient population by nearly 75%.

Over the longer run, Vertex hopes to grow by launching drugs outside of the CF indication. The biotech hopes to soon advance its pain drug VX-150 into a pivotal late-stage study. Vertex is also working with CRISPR Therapeutics on developing gene-editing therapies for rare blood diseases beta thalassemia and sickle cell disease.

Think long term

All three of these stocks could swing up and down -- just as they have in recent months. The key for investors to succeed, though, is to think long term and not worry about temporary fluctuations.

All three of these stocks have strong growth opportunities. All three have great products and solid competitive advantages. While there's no guarantee that Square, Teladoc Health, and Vertex will generate huge gains in the near term, their long-term prospects make them great picks to buy in March and hold for many seasons to come.