HAPPY VALLEY, OREGON WEATHER: APRIL 2021
TEMPERATURES
April 2021 had larger-than-usual daily temperature variations due to the many days of clear, dry weather, with an Average Monthly Diurnal Range of 23.5°. The Maximum Daily Diurnal Range was 31.7° on the 15th (76.2°/44.5°) and the 21st (75.9°/44.2°), the least was just 8.0° on the 24th (53.9°/45.9°), the day with the greatest rainfall of the month.
Overall, Maximum Temperatures averaged more than +5.0° departures while Minimums averaged near-Normal departures (per the official Portland stations).
April began quite cool as the Average Minimum Temperature through the first 16 days of the month was 39.9°, with 10 of the first 12 days reaching ≤40°. In fact, this 16-day average was exactly the same as this past January’s full monthly Average, showing how chilly April began and how mild January was. This month produced the first April sub-freezing temperature since this station was established on May 29, 2014 as the Minimum sank to a frosty 31.7° on the 11th.
Maximum Temperatures averaged slightly above Normal over the first 15 days (61.1°), with the latter half of the month greatly exceeding the Normal and providing the majority of the departure from Normal. The year saw its first temperature of ≥70° on April 15th with 76.2° then hit the first reading of ≥80° just 2 days later as the month’s warmest temperature soared to 82.9° on the 17th followed by 82.3° on the 18th, the only 2 days to hit ≥80° this month.
PRECIPITATION
It was a record-dry April as only 0.58″ fell, just 14% of the month’s Normal of 4.07″. There were only 4 days of measurable rainfall the entire month, occurring on the 8th (0.06″), 10th (0.01″), followed by a 13-day dry streak until the month’s maximum rainfall of 0.26″ on the 24th, and in the last few hours on the 30th, 0.20″, this latter amount producing the month’s highest rain rate of 0.26″/hour.
Total Monthly Precipitation: 0.58″
Maximum Calendar-Day Amount: 0.26″ (24th)
Maximum Precipitation Rate: 0.26″/Hr. (2253 Hrs on the 30th)
≥0.25″: 1
≥0.50″: 0
≥1.00″: 0
MISCELLANEOUS
Sky Cover: 13 clear, 13 partly cloudy, and 4 cloudy days.
Barometric Pressure: Average Maximum/Minimum Barometer readings were 30.17″/30.04″, with the Highest Daily Value of 30.36” on the 8th & 11th, the Lowest Daily Reading of 29.71” on the 25th.
Relative Humidity: Maximum/Minimum Relative Humidity Averages were 83%/39%, having a Daily Maximum of 97% on the 8th, 25th, & 30th, Daily Minimum of just 18% on the 16th.
Dew Point: Average Dew Points were a Maximum/Minimum of 45°/34°, with a Daily Maximum of 59° on the 30th, Daily Minimum of 22° on the 12th-14th.
Wind: Average of 1.5 MPH, with the highest gust reaching 26 MPH from the NW on the 14th.
HAPPY VALLEY WEATHER FORM: APRIL 2021
Cover Photo: Wild Purple Iris, 4/29/2021.