Portland, OR Weather Forecast and Current Conditions

Day		Sky	High / Low	Precip	Wind	Humidity
Thu Mar 23		Rain Close Hourly	47º / 38º	92%	SW 18 mph	75%
12pm		Rain	47º	91%	SSW 17 mph	77%
1pm		Rain	45º	84%	SW 16 mph	79%
2pm		Rain	46º	90%	SSW 14 mph	72%
3pm		Rain	46º	70%	SSW 13 mph	76%
4pm		Light Rain	45º	59%	SW 13 mph	75%
5pm		Rain	45º	78%	SW 14 mph	72%
6pm		Showers	44º	45%	SW 11 mph	73%
7pm		Showers	43º	51%	SSW 9 mph	73%
8pm		Showers	43º	45%	SSW 9 mph	76%
9pm		Showers	42º	55%	SSW 10 mph	76%
10pm		Showers	41º	55%	SSW 10 mph	77%
11pm		Rain	41º	67%	S 11 mph	81%
Fri Mar 24		Rain View Hourly	46º / 36º	73%	SW 10 mph	73%
12am		Showers	41º	51%	SSW 9 mph	81%
1am		Rain	41º	64%	SSW 10 mph	83%
2am		Light Rain	40º	61%	SSW 10 mph	85%
3am		Showers	40º	58%	SSW 9 mph	84%
4am		Showers	40º	43%	SSW 9 mph	84%
5am		Showers	40º	47%	SSW 10 mph	82%
6am		Showers	40º	49%	SSW 8 mph	85%
7am		Showers	39º	52%	SSW 9 mph	86%
8am		Showers	40º	52%	SSW 8 mph	86%
9am		Showers	40º	54%	SSW 9 mph	84%
10am		Showers	41º	47%	SSW 10 mph	80%
11am		Showers	43º	55%	SSW 10 mph	77%
12pm		Showers	44º	54%	SW 10 mph	73%
1pm		Light Rain	46º	74%	SW 10 mph	68%
2pm		Rain	45º	74%	SW 10 mph	68%
3pm		Rain	45º	72%	W 10 mph	66%
4pm		Light Rain	46º	66%	W 10 mph	62%
5pm		Showers	45º	57%	WSW 10 mph	65%
6pm		Showers	44º	45%	WSW 8 mph	65%
7pm		Showers	43º	41%	SW 8 mph	66%
8pm		Showers	42º	45%	SW 7 mph	70%
9pm		Showers	41º	52%	SW 8 mph	73%
10pm		Showers	40º	49%	SW 6 mph	75%
11pm		Showers	40º	49%	SSW 6 mph	79%
Sat Mar 25		Rain/Snow View Hourly	46º / 35º	69%	SSW 8 mph	77%
12am		Showers	39º	48%	SSW 6 mph	81%
1am		Rain/Snow Showers	39º	55%	SSW 7 mph	83%
2am		Rain/Snow Showers	38º	46%	SSW 6 mph	85%
3am		Rain/Snow Showers	38º	56%	SSW 6 mph	86%
4am		Snow Showers	38º	54%	SSW 5 mph	87%
5am		Few Snow Showers	38º	34%	SSW 5 mph	87%
6am		Cloudy	38º	24%	SSW 5 mph	88%
7am		Snow Showers	37º	42%	SSW 5 mph	88%
8am		Snow Showers	37º	51%	S 5 mph	90%
9am		Rain/Snow Showers	38º	52%	SSW 6 mph	87%
10am		Light Rain	39º	69%	SSW 7 mph	84%
11am		Light Rain	41º	62%	SSW 7 mph	81%
Sun Mar 26		Rain/Snow Showers	47º / 33º	54%	S 7 mph	79%
Mon Mar 27		Partly Cloudy	56º / 42º	22%	ENE 11 mph	60%
Tue Mar 28		AM Showers	56º / 38º	36%	ENE 13 mph	53%
Wed Mar 29		Partly Cloudy	59º / 39º	24%	ENE 10 mph	60%
Thu Mar 30		AM Showers	57º / 39º	33%	SSW 9 mph	65%

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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.