Passport/visa

You can apply visa extension in immigration office before your tourist visa expires, visa on arrival if you have american passport..

So. Arrive with tourist Visa. Not just passport

Your passport needs to be valid for not less than 6 months prior to entry into Philippines.

It is. No problem  there

If you are a first world passport holder, for need of a greater explanation you are automatically granted 30 days, this can be extended upon arrival (within the international airport) to 59 days for a fee and negates a future need to visit an immigration office to do so but after 59 days you need to secure a further extension, you can do this for 3 years then must leave the country (visa run) then start the process again. If you want to extend at the airport make sure you arrive with Philippine Pesos in larger and smaller denominations to negate "we have no change Sir, scenario". So I would suggest 4 to 5K PHP as you will probably need a taxi also to get you to your accom. and other stuff.

To the OP, your passport is not your visa or visa versa, 2 different entities and as stated by stumpy must have 6 months validity or you won't board the plane.
You stated that your passport was good for one month when opening this thread or are you mixing/confused by the difference between the 2? A passport is the ability to travel, a visa is the ability to visit/stay.

What is the expiry date of your passport? Your profile says you are a US citizen and if so can simply book a flight to well over 100 countries without the need to secure a visa prior to booking your arrival, automatically stamped in most countries.

Google is our best friend and all your (most) answers can be found with a little research and little else.

Good luck and I do hope you enjoy PH. if and when you get there.

Cheers, Steve.

BTW only my opinion based on lose information.

My passport is good till 2025 i been in the Philippines multiple times before. Just never 30 plus days. My wife is a Filipina national.  Still there. I just wondered,  if i was there for 3 weeks and instead of coming back then. How would I extend my stay. Go to Immigration and get a extension? You mentioned i can get this at airport also. Who do i speak to? When they stamp my passport?thank you steve.