... of beginning and ending temperatures through 20oC, 25oC.The dates of beginning and ending temperatures through 20oC, 25oC are very important for defining the crop calendar and crop ... Nang)-1000.0-500.00.0500.01000.01500.02000.019611963196519671969197119731975197719791 981 1 983 1 985 1 987 1 989 19911993199519971999200120032005∆R(mm)Fig 8. Trend and variation of annual total rainfall (station Ho Chi Minh) -80 0.0-600.0-400.0-200.00.0200.0400.0600.0 80 0.019611963196519671969197119731975197719791 981 1 983 1 985 1 987 1 989 19911993199519971999200120032005∆R(mm)4. ... Vinh (North central region), Can tho and Bac Lieu (Mekong river delta). On the other hand, in winter-spring season rainfall is increasing trend which observed at Bac Giang, Ha noi, Nam dinh,...