climate characteristic of the entire Russian Far East is particularly pronounced
in Primorye. Solar rays heat the surface of both land and ocean, which
then cool non-uniformly. In winter, the land cools rapidly. At that time
of the year, cold, dense and heavy air masses are generated in the center
of the Asian continent (over Northern Mongolia and southern Eastern Siberia)
to form an area of high atmospheric pressure, the Siberian anticyclone.
At that very time, water
cools slower to lead to formation over the northwestern Pacific an area
of declined atmospheric pressure, the Aleutian minimum. Because of pressure
difference, overcooled, dense, dry air from Siberia flows to the warmer
ocean coastline. In this case, it fills the area over Primorye to rush
to the reduced pressure area over the Pacific.
Cold, but dry and sunny weather sets in
over Primorye. The prevalent winds in that period are westerly and northwesterly.
These air masses form a continental monsoon in winter to reach especially
significant force on the coast.
In summer, the land warms up quicker, and warm
air forms over it and the continent to form a low-pressure area. At that
time, the Pacific is colder than the land, and the pressure over it higher;
this is where the area of high air pressure forms. The moist and less warm
air from the ocean and seas rushes to the continent. This is how the Pacific
summer monsoon with southerly and southeasterly winds forms in Primorye.
In the first half of summer,
due to the fact that air masses are carried out from the Yellow, Japan
and Okhotsk seas, the summer monsoon is concomitant with drizzles. It does
not possess a large reserve of moisture to leave it chiefly on the coastal
ridges and hills. That is why in late spring and early summer (May and
June) we often have foggy rainy weather in Vladivostok, but again in Ussuriisk
100 km to the north, and moreover in Grodekovo and Spassk, there are many
more clear days at this time of the year.
In the second half of summer and early
fall, the monsoon embraces the entire territory of Primorye to carry large
amounts of moisture. This is the time of intensive and protracted torrential
rains, not infrequently accompanied by powerful cyclones coming from tropical
The continental winter monsoon noticeably
prevails over the sea monsoon: northwesterly and northerly winds prevail
in Vladivostok from September to March, and in Partizansk even from September
to April. Precisely for that reason, the number of sunny days is so great.
Again, that is why Primorye has such unusually cold weather for such low
latitudes in winter. The mean temperature in Vladivostok in January is
minus 14.4oC, while
in Sochi, situated on the Black Sea coast on about the same latitude, the
mean air temperature in January is plus 6.1oC.
Depending on the direction in which
ridges and river valleys extend, and on the nature of sea coasts in some
Primorye sites, the winds in near-ground layers may change their basic
directions. Relief specifics and the direction of the coastline lead to
forming in Primorye of local winds, breezes, foehns, and hot dry winds.
Breezes are observed in protected
inlets of Japan Sea coastline, in narrow coastal strips. Mountains prevent
breezes from spreading inside the continent. In summertime, a daytime breeze
would normally start at 10-11 A.M. to continue till sunset. It would blow
from the sea to the heated coast. A nighttime breeze from cooled cost to
the sea would last 6-7 hours. During the cold period of the year, due to
strong cooling of land at nighttime, the diurnal breeze would be less protracted.
Sometimes in winter relatively warm
dry winds, foehns, arise in coastal areas. They form when air streams flow
over mountain ridges. In settling, the air heats to become drier. In this
case, the temperature of ground air layers rises and winter direction changes.
In spring, foehns hasten snow melting.
Hot dry winds УvisitФ the western
districts of Primorye, penetrating from Northeast China and Mongolia. The
most intense, often recurrent hot dry winds are characteristic of the Khanka
Plain in April and May.