HAPPY VALLEY, OREGON WEATHER: DECEMBER 2022
TEMPERATURES
December 2022 at Portland’s three official stations reported Average Temperature Departures-from-Normal ranging from -2.6° at the Portland International Airport (PDX) to -3.8° at the Portland National Weather Service Forecast Office (WFO) in the Park Rose neighborhood. Through the first 2/3 of the month, the weather was fairly uneventful temperature-wise.
Here in Happy Valley, through the first 21 days, Maximum Temperatures only varied by 10.9°, ranging from 37.2° to 48.1°. Polar air briefly invaded the area beginning in the early afternoon of the 21st, dropping to 21.2° by midnight, which would become the Maximum on the 22nd (the coldest in the area since 2014) when it continued to fall until after sunrise, never getting any warmer that day. In fact, the midday Max. on the 22nd would only reach 19.9°. One more cold day followed on the 23rd (Max. of only 31.5°) then moderation quickly came for Christmas, bringing the month’s first Max. of ≥50° on Dec. 25th and monthly Max. of 54.9° on the 27th, with no more cold air/freezing weather through year’s end.
Minimum Temperatures varied a bit more than Maximums through the first 20 days, ranging from 26.1° to 41.9°, a spread of 15.8°, before plunging with the polar air on the 21st. Minimums dropped to a monthly low of 16.8° on the morning of the 22nd and 17.1° on the 23rd but rebounded to remain above freezing from the 25th-31st, with the monthly High Minimum of 43.3° on the 26th. Overall, 11 days fell to ≤32° and 2 days slipping to ≤20. Splitting the month in two, the Average Max./Min./Mean Temperatures were thus: 1st-20th, 41.9°/34.0°/37.9°; 21st-31st, 44.7°/34.0°/39.3°, indicating how brief the late-in-the-month cold spell was as it was quickly balanced by milder temperatures in the final week. The month’s greatest diurnal range was 17.1° on the 24th (48.5°/31.4°), the least being just 2.0° on the 11th (42.6°/40.6°).
HAPPY VALLEY DECEMBER 2022 STATS:
PRECIPITATION
The first 17 days of the month were fairly ho-hum, with 2.28″ of total precipitation falling on 8 days prior to a dry period. The season’s first snowfall of ≥1.0″ occurred on the 4th when 1.2″ was measured, bringing the season total up to 1.4″., followed by 0.5″ of Ice Pellets falling on the 22nd-23rd, mixing with Freezing Rain, at times, accreting to 0.2″. Beginning on the 18th marked an extended wet period, with only the 22nd not having measurable precipitation through the end of the month as Atmospheric River began affecting the area. The heaviest rain fell from the 25th-28th, totaling 3.92″, and bringing the Maximum 24-Hour amount of 2.20″ from the 26th-27th. More heavy rain rounded out the month with 1.02″ falling on the 30th-31st. The precipitation from the 18th-31st totaled 5.74″ of the month’s 8.02″, representing 72% of the total. The monthly total of 8.02″ was 109% of the average of 7.33″.
Maximum Precipitation Rate: 3.69″/Hour (2th at 02:08 Hrs, Automated Gauge).
Maximum Calendar-Day Amount: 1.2″ (4th)
≥0.25″: 10
≥0.50″: 6
≥1.00″: 1
≥0.25″: 10
≥0.50″: 7
≥1.00″: 2
OTHER OBSERVATIONS
Sky Cover Days: 5 Clear, 3 Partly Cloudy, and 23 Cloudy.
Barometric Pressure: Average Maximum/Minimum readings were 30.14″/29.89″, with the Highest Daily Value of 30.46” (21st & 22nd), the Lowest Daily Reading of 28.99” (27th, the lowest recorded at this location since being established in 2014).
Relative Humidity: Maximum/Minimum Averages were 95%/84%, having a Daily Maximum of 98% (9th, 24th-27th, & 30th); Daily Minimum of 54% (22nd).
Dew Point: Averages were a Maximum/Minimum of 40°/31°, with a Daily Maximum of 54° (26th & 27th), Daily Minimum of just 5° (22nd).
Wind: The Daily Average Speed was 1.6 mph from the S, and the highest Daily Average was 8.2 mph from the NNE (22nd, supplying a Wind Chill down to 3.5°); the Daily Average Gust was 14.0 mph and the Highest Gust reached 36 mph from the SE (27th).
HAPPY VALLEY MONTHLY WEATHER FORM: DECEMBER 2022 (click the month to access a pdf of the form).
For the three official Portland National Weather Service weather stations, here is Temperature and Precipitation data for each location for DECEMBER 2022:
The 3 official Portland stations were well-below Normal temperature-wise, continuing the chilly weather from November 2022. Here are the periods of record for data for these stations:
Portland – Downtown (currently at KGW-TV) – Period of Record: since 1/1871
Portland International Airport (PDX) – Period of Record: since 11/1940
Portland – National Weather Service Forecast Office (WFO) – Period of Record: since 2/1996
This December’s Max/Min/Mean Temperatures and Departures from Normal (for 30-Year Period 1991-2020):
– PDX Airport: 43.8°/34.1°/39.0° (-3.1°/-2.1°/-2.6°)
– Downtown: 42.9°/34.4°/38.6° (-3.0°/-2.9°/-3.0°)
– WFO: 41.7°/32.4°/37.1° (-4.0°/-3.7°/-3.8°)
This December’s Precipitation and Departures from Normal (for 30-Year Period 1991-2020):
– PDX Airport: 7.76″ (+1.99″)
– Downtown: 7.36″ (+0.01″)
– WFO: 7.62″ (+0.66″)
Cover photo: Snowfall 12/4/2022.