Levin is closer to the Tasman Sea than Palmerston North, and the wind difference is noticeable. Horowhenua's coastal settlements, Waitārere Beach, Hōkio Beach, Waikawa Beach, sit in exposure zones where cladding fixings, window joinery and roof edge detailing need to be specified for salt air and sustained wind-driven rain. A design that works inland in Feilding may need a step up in weathertightness specification at the coast.
The district sits along the Horowhenua dune belt, a band of coastal sand dunes running behind the beaches. Some sections, particularly near the coast, have sandy, free-draining soils with variable bearing capacity. Others on the horticultural flats have deep, productive soils that are fine for gardens but can mean higher water tables and seasonal ground movement. Geotech before design is sensible on any section you haven't built on before.
Levin township itself is relatively sheltered compared to the beaches, but still windier than central Palmerston North. The district has a mild climate with reliable rainfall, good for the market gardens the area is known for, but that rainfall combined with wind means E2 junction design matters on every elevation, not just the weather side.