Weather for Marshalltown Muni, IA - Marshalltown Muni, IA Weather, Current Weather in Marshalltown Muni, IA. Local weather report for Marshalltown Muni, IA, Local Marshalltown Muni, IA weather. Forecast for Marshalltown Muni, Iowa, Marshalltown Muni, IA weather forecast. Find your local Marshalltown Muni weather forecast. Marshalltown Muni, IA weather conditions.