Time waits for no investor, and we just rolled into June, 2023. The immediate rearview mirror shows a rollicking market with inflation worries coming and going, a narrowly averted default on the U.S. government's debt, and an inspiring recovery from the dark days of 2022. The S&P 500 (^GSPC -0.88%) index has posted a total return of 12% year to date, and the more volatile Nasdaq Composite (^IXIC -2.05%) scored a 27% total gain over the same period.

Many news sites, investor hangouts, and economic analysis outlets are using the start of a new month to provide forecasts for what the stock market will do in June. But I'm not going to tell you where the S&P 500 is going next, how far the Nasdaq Composite index will rise or fall this month, or what the Federal Reserve will say at the next interest-rate update.

Because I don't know. And none of it really matters in the long run.

So I'm not here to give you any detailed calculations and projections for the month ahead. Instead, I want to remind you that Warren Buffett, master investor (and some might say possessor of Tolkien's Rings of Power) never tries to time the market -- and neither should you.

"The interesting thing is, we obviously have no idea what the stock market is going to do when it opens on Monday," Buffett said at Berkshire Hathaway 's (BRK.A 1.18%) (BRK.B 1.30%) annual meeting of 2022. He added:

We never have, and we never will. Charlie and I, in all the time we've worked together, I don't think we've ever made a decision where either one of us has said or even thought that we should buy or sell based on what the market is going to do. Nor, for that matter, on what the economy is going to do. We just don't know.

There you have it. Warren Buffett doesn't know what the market and the economy will do in the short term. He invests for the long haul, with an ideal holding period of "forever."

So let me tell you what the market will do in June, just as it did in May, and in 2022, and at any time since the stock market opened up in the mid-1800s.

^SPXTR Chart

^SPXTR data by YCharts.

1. The market will be unpredictable

Stock prices will go up some days and down sometimes. That's the nature of the market, and there are exceptions to every seemingly set-in-stone pattern.

For example, the S&P 500 fell 19.8% in 2022, and some would say that every day felt like a struggle. And it's true that last year saw more bad market days than good ones.

But what if I told you that the S&P 500 posted 107 single-day gains last year, or that the largest move of any kind was a 5.5% jump on November 10? Even the worst years have plenty of good days, just as the best ones come with a couple of stinkers. The same idea holds true on a month-by-month basis, too; the S&P 500 delivered positive returns in March, July, October, and November of 2022, for example.

There will be surprises, shocks, and events that no one saw coming. This is the nature of the market, and it's why trying to predict short-term movements doesn't make sense.

2. Quality companies will keep winning

Companies with strong financial results, good management, and a competitive edge will continue to do well in the long haul. They may of course face short-term challenges, but their underlying strength will help them weather these storms. If you own shares in these companies, hold onto them. If you don't, consider whether they might be a good addition to your portfolio.

And maybe if you own some companies that don't fit this description, then you might want to rethink those holdings. Great investments are almost always built for long-term success, after all. The latest flash in the pan is more of a gamble than an investment.

3. Long-term investing will be the best strategy in June, in 2023, and at any time

There are many ways to invest for long-term success. In every case, "time in the market" is far more important than "market timing." For example:

  • If you want to maximize the safety and minimize the amount of time you put into your investments, an index-tracking mutual fund or exchange-traded fund (ETF) could be right for you. This way, you get the ultimate diversification with dozens or even hundreds of stocks across a wide range of markets, industries, and categories.
  • Value investors like Warren Buffett focus on outstanding businesses whose stocks are trading at affordable prices. You can put together a diversified portfolio of these quality-at-a-disount investments, check up on them once in a while, and sleep soundly while your wealth builds at a moderate pace but limited risk.
  • If high-octane growth stocks are more to your liking, you should still look for firecrackers with staying power. Sure, it's great to find the biggest winner of June 2023, but will you cash in your winnings before the temporary gains fade away? You know what Warren Buffett said about market timing -- most people get it wrong most of the time. So what you really want is a diverse collection of high-growth business ideas that look ready to deliver disruption and business growth for years to come. This is a more intense approach where the ups and downs can come and go more often. But you still need to avoid panicking when something goes awry in the short term and try to stick with your winners over time.

These are the "predictions" I can confidently make for June and for any other month. Timeless truths never go away. They are based not on speculation or guesswork but on the timeless principles of investing that have been proven to work over the long term.

And I'm pretty sure Warren Buffett would agree.