The four schools – Montfort College, Regina Coeli College, Sacred Heart School and Vachirawit Shchool – are located on Charoen Prathet Road.
The Prince Royal's School on Nawarat Road continued classes on Friday although the road was also flooded.
Several other roads were also under water. The Nimmanahemin Road was under 30cm high water. The road around the Khu Mueang canal and the road to Wing 41 were also flooded.
The Sri Ping Mueang and Kard Kom communities, which are the lowest areas in Chiang Mai downtown, were flooded with the water level varying from half a metre to over one metre.
The residents of the communities said the flash floods happened very quickly at around 2am.