Average fixed mortgage rates in the U.S. fell in the latest week, according to mortgage-finance company Freddie Mac (FMCC), as the spring home-buying season draws closer.

Freddie Mac Deputy Chief Economist Len Kiefer noted Thursday that housing data was mixed during the latest week. Housing starts declined during February, though housing permits--an indicator of future activity--improved. Meanwhile, homebuilders remained confident about home sales in the future despite a measure of homebuilder confidence declining again in March.

For the week ended Thursday, the 30-year fixed-rate mortgage averaged 3.78%, compared with 3.86% a week earlier and 4.32% a year earlier. Rates on 15-year fixed-rate mortgages averaged 3.06%, compared with 3.1% the previous week and 3.32% a year earlier.

Five-year Treasury-indexed hybrid adjustable-rate mortgages, or ARMs, on average, were at 2.97%, compared with 3.01% the previous week and 3.02% a year earlier. One-year Treasury-indexed ARM rates on average were 2.46%, unchanged from the previous week and down slightly from 2.49% a year earlier.

Write to Tess Stynes at tess.stynes@wsj.com

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