A stuty has been made of the summer and winter temperature variations in vari-ous regions of the northern hemisphere during the years 1873-1950 with 10-year run-ning means as a measure of the secular changes. It leads to reveal that trends are dif-ferent with different regions. On 40°N, there has existed a general warming up, begin-ning in 1912 in winter (January) and in 1932 in summer (July); whereas no similar trend is discernible from the data and the departure curves constructed with them re-presenting temperature variations on 20°N since the commencement of the present cen-tury. It is noteworthy that increases in temperature are more pronounced in winter than in summer. This is a feature particularly marked in the Pacific and Atlantic sectors. In winter the correlation is十0.84 between Asia and Europe, but negative between Asia and North America. As regards the summer conditions, variations in Asia are better correlated with those in the Pacific and North :lmerica than with those in Europe, and negative correlations obtain in the case between Asia and Atlantic. A comparison of 10 year running means of January and July temperature diviations with pressure difference of latitudes 30°-50°N of corresponding regions has brought out that both agree in their directions of change, the correlation in Asia being in the neighbourhood of 十0.70. In Eastern Asia, increases in winter pressure ov,:r the continent, which may be considered as an indication of strong winter monsoon, are in general associated with colder winters;and a drop in summer pressure, probably a factor for stronger develop-ment of southeastern and southwestern monsoons, is usually accompanied with a rise in summer temperature.