How long will it likely take me to cross the Pacific ocean in a small motorless sailboat?

If I depart from the Oregon coast late this month, how long will it take for me to cross the Pacific?

I plan to use the California and Southern Equatorial currents, eventually making landfall in New Guinea or the Philippines (if everything goes as I expect). My sailboat is quite modest, but I'll have plenty of supplies and I'll be in no hurry.

So, how long might this journey take? How much variation might there be?

Also, how much difference will the time of year make? Would there be a more optimal time of year to do this?

Thanks very much!

a long time

Based on this question, there is no way in hell that you are going to be ready to make an ocean passage on a sailboat (motorless or otherwise) in the next 19 days.

Find a good sailing school, one certified by either US Sailing or ASA. Take their entire course curriculum, starting with basic keelboat and basic cruising, all the way through celestial navigation and ocean passage-making. You could theoretically complete this in one year, although five years is probably more realistic. That's okay. I promise, the Pacific Ocean will still be there waiting for you when you're ready. And then, crossing the ocean in a motorless sailboat will be an amazing adventure, instead of a successful suicide attempt.

One guy took about 30 days to sail from California to Hawaii in a 12 foot long sailboat. That's not a typo. But he kept his motor on at idle the whole way including when he got into the doldrums (i.e., no wind).

You'll most likely sail at 6 mph. So, if you're sailing 4,000 miles, that would be 666 hours. 24 hrs a day, that is 27 days. However, you won't alway maintain that speed due to doldrums and storms. Plus, you'll want to follow currents if you can. That is 666 hrs of cruising time. So, if you anchor while sleeping, then add that down time to your trip.

Get radar, GPS/routing software, and an autopilot. I recommend "The Cap'n" software. Most importantly, get someone else to watch (and steer) while you're sleeping.

I did it in 4 days in my inner tube. With my butt in the water and eating nothing but baked beans.

It's wonderful to dream. But this is reality time- it will take a minimum of 3 years of preparation and training to attempt a trip of this magnitude, and the cost would be staggering- rescue plans put in place should the unforeseen happen. Plus the odds of being successful is very low- it has not been done by very many people, and most experienced difficulties of some kind. If you try it without being properly prepared, you wont make it.