After a one-week turn around in mortgage rates, the 30-year, fixed-mortgage rate fell again to 4.27%, according to the Zillow Mortgage Marketplace weekly update. This is still 20 basis points above the historical low hit two weeks ago. Zillow said the current 15-year, fixed-average rate is 3.64% and the rate for a 5-1 adjustable rate mortgage is 3.03%. That type of mortgage maintains a steady rate for five years and then is adjusted annually thereafter. Regionally, 30-year rates vary, but the majority of states witnessed a decline. California’s average rate dropped to 4.23% last week from 4.36% prior. Rates in New York also fell substantially to 4.23% from 4.34% the previous week, while Pennsylvania’s rate decreased to 4.25% from 4.41%, and Washington saw its average rate slump to 4.26% from 4.32%. The current rate in Texas increased week-over-week, up to 4.32% from 4.31% last week, as is Florida’s, up to 4.27% from 4.25% Rates in Massachusetts remained at 4.35%. Zillow bases its averages on real-time mortgage quotes from lenders registered with the company. The national average comes from thousands of daily quotes by anonymous borrowers through the Seattle-based company’s website. Write to Christine Ricciardi.