Portland, OR Weather Forecast and Current Conditions

Day		Sky	High / Low	Precip	Wind	Humidity
Sun Nov 27		Rain Close Hourly	-º / 38º	93%	SW 6 mph	89%
7pm		Showers	43º	55%	SSW 3 mph	89%
8pm		Rain	43º	78%	SSW 4 mph	89%
9pm		Rain	43º	93%	SSW 4 mph	88%
10pm		Showers	43º	41%	SSW 6 mph	88%
11pm		Few Showers	42º	32%	SSW 6 mph	90%
Mon Nov 28		PM Showers View Hourly	44º / 32º	42%	WSW 6 mph	76%
12am		Light Rain	41º	64%	SW 6 mph	90%
1am		Light Rain	41º	63%	SW 6 mph	89%
2am		Showers	41º	55%	SW 6 mph	89%
3am		Showers	40º	53%	SW 4 mph	90%
4am		Showers	40º	41%	SW 5 mph	88%
5am		Showers	39º	42%	SW 5 mph	89%
6am		Showers	39º	44%	SW 5 mph	88%
7am		Mostly Cloudy	39º	24%	SW 5 mph	87%
8am		Partly Cloudy	39º	24%	SW 5 mph	87%
9am		Partly Cloudy	40º	23%	SW 4 mph	86%
10am		Partly Cloudy	41º	21%	SW 5 mph	81%
11am		Partly Cloudy	43º	23%	WSW 5 mph	74%
12pm		Mostly Cloudy	43º	24%	WSW 5 mph	70%
1pm		Showers	44º	42%	WSW 6 mph	67%
2pm		Showers	44º	43%	W 6 mph	67%
3pm		Few Showers	43º	31%	W 5 mph	69%
4pm		Partly Cloudy	42º	21%	W 5 mph	73%
5pm		Partly Cloudy	40º	23%	SW 4 mph	78%
6pm		Mostly Clear	39º	21%	S 3 mph	77%
7pm		Mostly Clear	38º	14%	SSW 4 mph	79%
8pm		Mostly Clear	37º	14%	S 3 mph	81%
9pm		Partly Cloudy	36º	15%	S 3 mph	81%
10pm		Partly Cloudy	35º	13%	S 3 mph	82%
11pm		Partly Cloudy	35º	15%	SSE 3 mph	84%
Tue Nov 29		PM Light Rain View Hourly	41º / 39º	66%	SSE 9 mph	84%
12am		Partly Cloudy	34º	11%	SSE 2 mph	85%
1am		Partly Cloudy	34º	8%	SE 2 mph	86%
2am		Partly Cloudy	33º	8%	SSE 2 mph	87%
3am		Partly Cloudy	33º	8%	SSE 2 mph	89%
4am		Partly Cloudy	33º	21%	SSE 2 mph	89%
5am		Mostly Cloudy	33º	21%	SSE 2 mph	90%
6am		Cloudy	33º	21%	SSE 2 mph	90%
7am		Cloudy	34º	23%	SSE 3 mph	89%
8am		Cloudy	34º	22%	SSE 3 mph	91%
9am		Cloudy	35º	21%	SSE 5 mph	89%
10am		Cloudy	37º	24%	SSE 6 mph	86%
11am		Cloudy	39º	24%	SSE 7 mph	83%
12pm		Cloudy	39º	24%	S 8 mph	82%
1pm		Showers	40º	54%	S 8 mph	81%
2pm		Light Rain	40º	63%	S 8 mph	80%
3pm		Light Rain	40º	65%	S 8 mph	83%
4pm		Light Rain	40º	61%	SSE 9 mph	83%
5pm		Light Rain	40º	66%	SSE 9 mph	83%
6pm		Light Rain	40º	66%	SSE 9 mph	83%
Wed Nov 30		Rain	46º / 38º	89%	S 17 mph	86%
Thu Dec 1		Showers	41º / 36º	71%	SSE 8 mph	85%
Fri Dec 2		Showers	44º / 38º	50%	SSE 12 mph	77%
Sat Dec 3		Rain/Snow Showers	42º / 34º	58%	SE 11 mph	79%
Sun Dec 4		Rain/Snow Showers	41º / 32º	40%	SE 7 mph	80%

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General Weather Conditions in Portland, OR

The coast range provides limited shielding from the maritime influence of the Pacific Ocean. The Cascade Range provides a steep high slope for the lifting moisture-laden westerly winds, which produces heavy rainfall in the western Cascade piedmont region. They also form the barrier for the Columbia River basin region and dry continental air masses. Airflow is usually northwest in Portland in spring and summer and southeast in fall and winter, interrupted occasionally by outbreaks of dry continental air east through Cascade passes and across ridge tops. When such an outbreak occurs, extreme high or low temperatures are usually experienced in the Portland area.

Portland has a very definite winter rainfall climate. About 88 percent of the annual total occurs in October through May, nine percent in June and September, while only 3 percent comes in July and August. The average annual precipitation is 37.33 inches (948.2 mm). December is the wettest month, and July, the driest. Precipitation is mostly rain; on the average only 17 days each year have snow. Snowfall is seldom more than a couple of inches, and it generally lasts only a few days. The annual average is only seven inches (178 mm) with January having the most. Snowfall has fallen in every month from November through May. The greatest measured snowfall in 24 hours was just under 11 inches (279 mm) recorded in January 1971.

Each season is clearly marked. Winter is mild, cloudy and wet with southeast surface winds predominating. Summer is marked by mild temperature, with prevailing northwest winds and very little precipitation. Fall and spring are transitional in nature, with frequent periods of ground fog. An average of 18 days during October record foggy conditions while only three days during July can expect fog. At all times, incursions of marine-tempered air are a frequent moderating influence. Outbreaks of continental air from east of the Cascade Mountains flow through the Columbia Gorge at near sea level and spread into the Portland area associated with the movement of Pacific storms offshore on a northeast storm track. In winter this brings the coldest weather, and the extremes of low temperature are registered in the cold airmass. Freezing rain and ice glaze often are transitional effects. In summer the hot, dry, continental air brings the highest temperatures. Extreme temperatures below zero are very infrequent. The absolute lowest ever reached is 3°F below zero (-19.4°C) recorded in February 1950. Extreme temperatures above 100°F (37.8°C) have occurred during each month from May through September; the absolute highest temperature is 107°F (41.6°C) recorded in July 1942, July 1965 and August 1981. Temperatures 90°F (32.2°C) or higher are reached every year, but seldom persist for more than 2 or 3 days before the warm spell is broken by a flow of cool, moist air from the ocean. The average annual temperature for Portland is 53.9°F (12.1°C). The average maximum is 63°F (17.2°C) while the average minimum is 45°F (7.2°C).

Destructive storms are infrequent in the Portland area. Surface winds seldom exceed gale force. Thunderstorms are infrequent, occurring, on average, only seven days each year. Tornadoes with the funnel cloud reaching the ground are rare and there are rare occurrences of heavy rain even though winter rains may persist for days at a time. Ice forms occasionally, but it is seldom heavy enough to affect navigation seriously, although navigation by small craft may be difficult.