When the Marines moved to the west, the winter was just ending. It had begun in November and was characterized by frequent light snowfalls but otherwise generally clear skies. Snow and wind storms seldom occurred in western Korea. From November to March the mean daily minimum Fahrenheit readings ranged from 15° to 30° above zero. The mean daily maximums during the summer were between the upper 70s and mid-80s. Extensive cloud cover, fog, and heavy rains were frequent during the summer season. Hot weather periods were also characterized by occasional severe winds. Spring and fall were moderate transitional seasons. Steep-sided hills and mountains, which sloped abruptly into narrow valleys pierced by many of the rivers and larger streams, predominated the terrain in the I Corps sector where the Marines located. The most rugged terrain was to the rear of the JAMESTOWN Line; six miles northeast of the Munsan-ni railhead was a 1,948-foot mountain, far higher than any other elevation on the Marine or Chinese MLR but lower than the rear area peaks supporting the Communist defenses. Ground cover in the division sector consisted of grass, scrub brush, and, occasionally, small trees. Rice fields crowded the valley floors. Mud flats were prevalent in many areas immediately adjacent to the larger rivers which intersected the division territory or virtually paralleled the east and western boundaries of the Marine sector. The transfer from the Punchbowl in the east to western Korea thus resulted in a distinct change of scene for the Marines, who went from a rugged mountainous area to comparatively level terrain. Instead of facing a line held by predominantly North Korean forces the division was now confronted by the Chinese Communists. The Marines also went from a front that had been characterized by lively patrol action to one that in March 1952 was relatively dormant. With the arrival of the 1st Marine Division, this critical I Corps sector would witness sharply renewed activity and become a focal point of action in the UNC line. _Organization of the 1st Marine Division Area_[18] [18] Unless otherwise noted, the material in this section is derived from: _PacFlt EvalRpt_ No. 4, Chap. 9; 1stMarDiv, 1stMar, 5thMar, 7thMar, 11thMar ComdDs, Mar 52; 1st KMC RCT Daily Intelligence and Operations Rpts, hereafter KMC Regt UnitRpts, Mar 52; Kimpo ProvRegt ComdDs, hereafter KPR ComdDs, Mar-Apr 52.