I have a site that is in the job sector niche in South Africa. According to Google Adwords Keyword planner, I search for a particular keyword (using the "Only show closely related ideas", targeting South Africa options) and the planner says the particular keyword only get about 480 searches a month. I then check the Google Analytics account for this same site and under Aquisition > Keywords > Organic Keywords. The stats show that for the same keyword (with other keyword terms related to it) bring in a total of 2,763 visitors in the last 30 days!! Lesson learnt: Use adwords keyword planner to get possible keywords and their estimated traffic but not for getting exact no of visitors expected
From the support website: "Keep in mind that historical stats like average monthly searches are only shown for exact match. For example, let's say your keyword is dark chocolate. If you want to check that keyword's average monthly searches, we'll show you the same exact match stats whether you use a broad, phrase, or exact match type with dark chocolate." So basically, what you're experiencing is normal.
@YJunK - When i check in analytics for the same exact keyword WITHOUT other keyword terms related to it, the analytics stats show 899 searches compared to Adwords 480 searches
Adwords shows search results from Google only, while analytics doesn't show organic traffic from google searches. Google switched to HTTPs, so it's not likely you'll get to know where your organic google traffic comes from. Basically, the discrepancy comes from the fact that people get to your site from other search engines, that are not Google.