Buying stocks may not be your priority at the moment. You might be busy with plenty of year-end things, like finishing up projects at work or planning for the holidays.

The stock market's performance probably isn't inspiring you to drop everything and finish up the year with some investing, either. All three indexes slipped into bear market territory this year, and December often is a quiet month when it comes to corporate news. So the coming days may not bring major catalysts for stock movements.

But this doesn't mean you should forget about the market until 2023. In fact, right now is an ideal time to keep investing. Let's talk about why -- and what you should do before we start a new year.

A great investing month

December is a great investing month because it generally isn't loaded with earnings reports and other corporate news. You have the opportunity to take your time evaluating a company's past reports and financials, and share prices often don't move tremendously right around the holidays. So it's the perfect time to study up on a company -- and easily snap up a stock at a price you like.

This particular December is an especially good time to invest because the bear market has left many stocks trading at bargain valuations. For instance, e-commerce giant Amazon (AMZN -1.64%) is trading at its lowest in relation to sales since 2015. Telemedicine-leader Teladoc Health (TDOC -0.07%) is trading at its cheapest ever by that measure.

AMZN PS Ratio Chart

AMZN PS Ratio data by YCharts.

Electric-vehicle maker Tesla (TSLA 12.06%) saw its valuation -- in relation to forward earnings estimates -- cut in half in just six months.

TSLA PE Ratio (Forward) Chart

TSLA PE Ratio (Forward) data by YCharts.

It's impossible to predict when the general market will recover. But we do know bear markets always lead to bull markets. And the average bear market lasts about a year, so today's situation of low valuations won't last forever.

That means when valuations look like a bargain -- or even reasonable -- it's a smart idea to buy. If you invest for at least five years, you've got a solid chance of winning your bet.

Defying the bear market

This December also offers another advantage. Since we've been in the middle of a downturn for a while now, we can see which companies managed to defy such a market. These stocks may boost your portfolio if the downturn continues -- and they may be investments to hold onto during future tough market times.

An example is healthcare-company McKesson (MCK 0.64%). The stock has outperformed the market this year.

McKesson is a fantastic safe stock. It distributes pharmaceutical products -- so doesn't carry the drug development risk. And rewarding shareholders is a priority. McKesson returned $1.6 billion to shareholders in the first six months of the fiscal year -- through stock buybacks and dividends.

What should you do right now?

What should you do before the new year? Evaluate your portfolio to see if you still believe in all of your positions -- or if you should lock in profits in certain stocks and put that cash into some new positions.

Don't be discouraged by declines this year, though. Instead, take a long-term view. That means looking at a stock's performance -- or considering future possibilities -- over at least five years.

You also may already have some cash set aside for opportunities as they arise. Consider putting some of it into stocks that have fallen to bargain valuations -- or those that have proven their resilience during tough times. You also may check out some players that are starting to rebound and showing momentum.

In any case, the worst thing you could do right now is shut the door to investing just because it's the end of a difficult investing year. The best thing you could do is keep your eyes open for opportunities before 2023 and beyond.