How often is Google Location History updated?

After a bit of research this is what I was able to find.
"Each time the phone was within range of a Wi-Fi access point, it would send its MAC address and SSID to Google’s servers. Using GPS (when available) and cell ID data, it can locate where that Wi-Fi access point is, which is then collected and stored to create the history you see on the map."

Keep that in mind with my personal experience of seeing it update as often as every single minute!

I do not believe configuration of the frequency is adjustable.

I hope this helps!