Portland, OR Weather Forecast and Current Conditions

Day		Sky	High / Low	Precip	Wind	Humidity
Thu Apr 25		Rain Close Hourly	55º / 50º	100%	SSW 16 mph	85%
12pm		Rain	53º	100%	S 13 mph	87%
1pm		Rain	53º	79%	S 14 mph	87%
2pm		Light Rain	54º	79%	S 15 mph	85%
3pm		Light Rain	54º	66%	S 16 mph	84%
4pm		Rain	54º	75%	SSW 16 mph	82%
5pm		Rain	55º	91%	SSW 15 mph	83%
6pm		Rain	55º	87%	SSW 14 mph	81%
7pm		Light Rain	55º	71%	SSW 12 mph	79%
8pm		Showers	55º	59%	SSW 11 mph	79%
9pm		Light Rain	54º	62%	SSW 10 mph	81%
10pm		Light Rain	54º	71%	SSW 10 mph	81%
11pm		Light Rain	54º	68%	SSW 10 mph	81%
Fri Apr 26		Light Rain View Hourly	55º / 48º	77%	SSW 11 mph	82%
12am		Rain	53º	75%	SSW 9 mph	83%
1am		Light Rain	53º	71%	SSW 9 mph	84%
2am		Showers	53º	54%	SSW 8 mph	84%
3am		Showers	52º	47%	SSW 8 mph	83%
4am		Showers	52º	49%	SSW 7 mph	84%
5am		Showers	52º	35%	S 7 mph	84%
6am		Showers	51º	50%	S 8 mph	86%
7am		Showers	51º	55%	S 9 mph	86%
8am		Showers	52º	51%	S 10 mph	84%
9am		Showers	52º	55%	S 11 mph	84%
10am		Light Rain	52º	64%	S 11 mph	83%
11am		Light Rain	53º	78%	S 10 mph	82%
12pm		Light Rain	53º	76%	SSW 11 mph	82%
1pm		Light Rain	53º	78%	SSW 10 mph	82%
2pm		Light Rain	54º	75%	SSW 11 mph	79%
3pm		Light Rain	54º	72%	SSW 10 mph	78%
4pm		Light Rain	54º	71%	SSW 10 mph	78%
5pm		Light Rain	54º	64%	SSW 9 mph	81%
6pm		Showers	54º	58%	SW 10 mph	79%
7pm		Showers	54º	53%	SW 8 mph	78%
8pm		Showers	54º	47%	SW 8 mph	79%
9pm		Showers	53º	42%	SSW 8 mph	79%
10pm		Showers	52º	41%	SW 8 mph	81%
11pm		Showers	52º	35%	SSW 7 mph	81%
Sat Apr 27		Showers View Hourly	55º / 50º	44%	SSW 11 mph	73%
12am		Showers	51º	35%	SSW 6 mph	81%
1am		Showers	51º	36%	SSW 6 mph	81%
2am		Few Showers	50º	33%	SSW 6 mph	81%
3am		Few Showers	50º	32%	SSW 5 mph	82%
4am		Cloudy	50º	24%	SSW 4 mph	82%
5am		Cloudy	49º	19%	SSW 5 mph	83%
6am		Cloudy	49º	21%	S 5 mph	84%
7am		Cloudy	49º	21%	S 6 mph	84%
8am		Cloudy	50º	21%	SSW 7 mph	82%
9am		Cloudy	51º	22%	SSW 8 mph	80%
10am		Cloudy	51º	21%	SSW 9 mph	78%
11am		Few Showers	52º	34%	SSW 10 mph	72%
Sun Apr 28		AM Showers	60º / 43º	42%	SW 11 mph	64%
Mon Apr 29		AM Showers	58º / 42º	47%	WSW 10 mph	59%
Tue Apr 30		Mostly Cloudy	64º / 45º	18%	SW 6 mph	55%
Wed May 1		Mostly Cloudy	66º / 49º	24%	SSW 9 mph	56%
Thu May 2		Showers	61º / 45º	50%	SW 11 mph	62%

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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.