Why does my Mac take a long time (30+ seconds) to find my home wifi?
In my professional experience, if you travel a fair amount and use hotel &amp; other free wifi nets, the list of preferred networks can grow unwieldy, and your home network may be way down on the list. @Robuust's suggestion should be amplified to include deleting all preferred networks in that list you may never use again, in addition to any regularly-used networks with connection problems.

In addition, I suggest that once you have re-established connection with your home wifi, that you drag it to the top of the list with this option:



Naturally, if it is your only network, this step is superfluous.

Additional information edit:

You might also want to try deleting the associated login key to this network in Keychain Access.