August started off with record heat on the 2nd and 3rd (103° and 105°, respectively) and, though no more Maximum Temperature records were set the rest of the month, the Mean Temperature was the warmest ever recorded for the Portland Airport (period of record back to 1940). The overall Average Maximum was 6.0° above normal, the second-highest August reading ever.

Top-5 Highest August Average Maximum Temperatures:

1. 88.1° (1967)
2. 87.1° (2017)
3. 86.2° (1986)
4. 85.5° (1981)
5. 85.0° (1972)

Minimum Temperatures were not as far from normal, the Average being 60.2°, a +2.2° departure, but still 6th warmest all-time. The only daily record High Minimum Temperature this month was on the 3rd with 66°, beating out the previous reading of 65° in 1947.

Top-5 Highest August Average Minimum Temperatures (plus 2017):

1. 61.4° (2014)
2. 60.9° (2013)
3. 60.7° (2004)
4. 60.5° (2015)
5. 60.4° (1997)
6. 60.2° (2017)

Though neither the August 2017 Average Maximum nor Minimum Temperatures were the warmest ever, the combination placed the Mean Temperature in 1st place all-time as only 2 days averaged 1 degree or more below normal.

Top-5 Highest August Mean Temperatures:

1. 73.6° (2017)
2. 73.1° (2014)
3. 72.9° (1967)
4. 72.4° (2015)
5. 72.3° (1986)

Seeing a pattern yet?

When looking at all months of the year, how does August 2017 compare?

Top-5 All-Time Highest Monthly Average Maximum Temperatures:

1. 88.1° (8/1967)
2. 87.5° (7/1985)
3. 87.1° (8/2017)
4. 86.7° (7/2015)
5. 86.5° (7/2009)

Top-5 All-Time Highest Monthly Average Minimum Temperatures (plus 2017):

1. 61.4° (8/2014)
2. 61.2° (7/1998)
3. 61.1° (7/2015)
4. 60.9° (8/2013)
5. 60.7° (7/1985 & 8/2004)

10. 60.2° (8/2017)

Top-5 All-Time Highest Monthly Mean Temperatures:

1. 74.1° (7/1985)
2. 73.9° (7/2015)
3. tie 73.6° (8/2017 & 7/2009)

5. 73.1° (8/2014)

When including the longer-term downtown locations (back to 1874) for the time prior to the airport period of record, Aug. 2017 would still be #1 for Highest Mean Temperature, exceeding the 72.3° (from 7/1906).

 

When looking at the number of days of ≥90°, the airport recorded 11 days, placing it in a 4th-place tie:

Top-5 Number of Days ≥90°:

1. 13 days (1967)

2. tie 12 days (1986 & 1977)

4. tie 11 days (2017 & 1972)

 

Top-5 Number of Days ≥95°:

1. Five-way tie with 6 days (2017, 1986, 1981, 1977, 1967)

 

Looking at the wider view, for the meteorological summer of 2017 (June-August):

Top-5 Highest Summer Average Maximum Temperatures:

1. 84.6° (2016)
2. 82.8° (1967)
3. 81.8° (2017)
4. tie 81.4° (1992 and 1985)

Top-5 Highest Summer Average Minimum Temperatures (plus 2017):

1. 59.8° (2015)
2. 58.8° (2009)
3. 58.5° (2004)
4. 58.4° (2014)
5. 58.3° (1998)

9. 57.6° (2017)

Top-5 Highest Summer Mean Temperatures:

1. 72.2° (2015)
2. 69.8° (2009)
3. 69.7° (2017)
4. 69.6° (2014)
5. 69.5° (2004)

So, the patterns are certainly showing that so many of the warmest summer records have been very recent, even with a rather long historical record of 78 years.

 

PRECIPITATION

As far as measurable precipitation, only a single day was recorded when 0.06″ fell on the 13th, halting the streak of 57 consecutive days without measurable rain (starting June 17th), the third longest such period since 1940. The all-time record is 71 days, ending on 9/1/1967. Had the rain not fallen this month on the 13th, the all-time consecutive-days streak would have been broken as no more rain has fallen as of Sept. 1st. The August total of 0.06″ places 2017 in a tie with 1940 as 12th driest, the driest being just a Trace on five occasions (the most recent being in 2012).

As we start September 2017, another heat wave is beginning and no rain is forecast for the next week, though smoke/haze should dominate the visibility from numerous wildfires burning to the north, east, and south of the Willamette Valley. Winds will soon shift, allowing that smoke to filter into the valley again.

NOTE: August 2017 data is considered preliminary until final verification by NWS and NCEI.

 

Cover photo courtesy of “flypdx.com”