Boise, Idaho – Temperatures dropping into the upper 20s overnight will create widespread frost conditions across the Treasure Valley, raising concerns for agriculture and early-morning travel through Monday morning.
According to the National Weather Service in Boise, a low-pressure system will keep colder-than-normal air in place through midweek, with overnight lows ranging from 24 to 35 degrees across the region. Cities including Boise, Nampa, Caldwell, and Ontario will see lows near 33 to 35 degrees early Monday, while colder pockets like Baker City and McCall could fall to 24 degrees.
Frost development is most likely between 2 a.m. and 8 a.m. Monday, especially in low-lying and rural areas. While major highways like I-84 are expected to remain mostly dry, isolated slick spots could form on bridges and overpasses during early commuting hours. Sensitive crops and outdoor plants face the highest risk, particularly in agricultural zones near Caldwell and Ontario.
Residents should cover plants, protect exposed pipes, and allow extra travel time during early morning hours. Temperatures will gradually rise each afternoon, reaching near 60 degrees Monday and climbing into the low 70s by Thursday and Friday as high pressure builds.
Cold overnight conditions will persist through at least Wednesday morning before a steady warming trend reduces frost risk later in the week. Additional advisories may be issued if temperatures trend lower.
