Here are the reasons for a discrepancy between what you see in Google SERP and what Ahrefs shows in Site Explorer:
Timing: Google SERPs can change pretty much any minute (or at least every few days). At Ahrefs, we strive for efficient use of our resources, so we currently do not update keywords faster than a few times per day. Keywords with higher search volumes are updated more frequently, often within 1–3 days, while those with lower search volumes are refreshed at regular intervals, typically in terms of weeks or months.
Location: SERPs can be different based on location. In Site Explorer, this is randomized within a single country. Choosing a more specific location can only be done in Rank Tracker. But even within a city or zip code, Google may vary results at a granular level.
Personalisation: It's also not a secret that Google serves different results to different people with the goal of helping people get better search results (Read more.) This can be based on factors like their search history and browsing patterns. For e.g, your neighbour may get a slightly different SERP for the same keyword due to the above factors.
Other Influencing Factors: Additional discrepancies may arise from elements such as SERP features (e.g., shopping ads, featured snippets, or video carousels) or Google’s ranking algorithm changes, which can cause fluctuations over time. Ahrefs bases its rankings on snapshots of the SERP, reflecting the most relevant features and elements at the time of sampling.
Any of the above 3 reasons or a combination of these can cause a discrepancy between what you see in Google SERP and Ahrefs' Site Explorer.
👉 Keywords with very low search volumes do not get regular SERP updates but can be manually updated if you have a Standard or higher plan