At the beginning of this summer season, high pressure air masses from
China still prevail to cover over Northern and Northeastern parts from time to
time causing the area still to be cool generally in the morning and cold in
some areas on some days. During daytime, the upper Thailand will be hot
generally. Until about middle March until April, heat low pressure air masses
covering the upper Thailand (Northern, Northeastern, Central and Eastern parts) from time to time cause the area to be
hot generally and very hot in many areas especially during late March until early April