Last Frost of the Year?

I'm wondering if this will be the last frost, at least in Eureka, this spring?

I was thinking the last expected day for frost was the middle of March, but I wasn't sure. You usually find rough estimates of the last day of frost in seed catalogs, but this table from the National Oceanic and Atmospheric Administration (.pdf file) makes it seem a little more complicated.

They break it down into probabilities and even further into low temperature expectations. So, the simplest way to put it is there's a 90% chance of the last frost date being around February 14. A 50% chance of it being around March 18 and a 10% chance of it being around April 19.

This seed catalog frost table says the last average frost around here in Spring is March 14. That goes along with my recollection.

I can't, for the life of me, remember when the last Spring frost was last year. Can anyone remember when that was?