One thing is almost certain about Apple's (AAPL 0.50%) fiscal third quarter: Part shortages and logistics challenges likely put a dent in the tech giant's sales. But the question is about the extent of the damage. Apple has experienced significant supply chain challenges for a while now -- and management said on Apple's fiscal second-quarter earnings call that shortages would have a "substantially" worse impact in fiscal Q3 than the prior quarter.  It's possible, however, that the negative impacts on Apple's business from the supply chain proved to be worse or more moderate than anticipated.

Whatever the case, we'll have a better idea of how Apple is faring later this month. The company is scheduled to report its fiscal third-quarter results on July 28. 

What to expect

To get some more context ahead of the iPhone maker's upcoming earnings report, investors can take a close look at Apple's results and commentary from management during the company's last earnings call. On it, Apple didn't provide any specific revenue guidance for the quarter due to "continued uncertainty around the world in the near term," explained CFO Luca Maestri. But he did provide some "directional insights" based on recent trends at the time of the call. Specifically, Maestri said he expected supply chain disruptions to negatively impact revenue by $4 billion to $8 billion. Additionally, the CFO said Apple anticipated softer demand in China due to COVID-related disruptions. A pause in Apple's sales in Russia is also expected to have a slightly negative impact on the quarter.

On a positive note, management said it anticipated a double-digit year-over-year growth rate from its services segment during fiscal Q3. Though Maestri said he expected the growth rate to be slower than the 17% growth the segment saw in fiscal Q2.

Given this background, the consensus analyst forecast is for Apple to report fiscal third-quarter revenue of $82.5 billion, up just 1% year over year. Of course, investors should note that this would be solid growth in light of both the anticipated supply chain challenges and an extremely tough year-ago comparison; revenue soared 36% year over year in the year-ago period. 

It's a wild-card quarter

While analysts' consensus forecast gives us a specific revenue number to consider in our context, investors shouldn't make the mistake of going into the quarter with a false sense of confidence about what the quarter could look like. These are unprecedented times with unusual challenges. It's extremely difficult to forecast where Apple's sales could fall for the quarter. Indeed, the highest analyst estimate is about $10 billion above the lowest projection for the period.

Further, investors would be wise to refrain from judging Apple's entire business based on whatever revenue figure the company reports in fiscal Q3. A better approach to analysis when the report comes out would be to consider the number and then listen to the earnings call for context to see what the impact was from supply shortages. This will help investors get a better idea of how demand is actually faring.

Mark your calendar and stay tuned. Apple's earnings report will be released after market close on Thursday, July 28.