HAPPY VALLEY, OREGON WEATHER: MAY 2021
TEMPERATURES
May 2021 averaged very close to normal for this area but the warmest Maximum Temperatures waited until the final 3 days when the 80s were reached each day, bringing the monthly Average Maximum Temperature from just below normal to a bit above normal. Until these final 3 days, just one day in the month had reached 80° (81.3° on the 16th), this value occurring during the month’s longest stretch of warm weather when Maximums remained ≥70° from the 11th-16th. The month’s highest Maximum of 86.4° on the 31st (Memorial Day) was the warmest since September 3, 2020 when it last reached 90° here (90.6°). Scattered throughout the month were 4 days when the Maximums failed to exceed 60°, the coolest being 57.6° on the 20th during one of the few cloudy days of the month.
Minimum Temperatures varied by just 13.9° during the month, with Minimums ranging from 40.0° (8th) to 53.9° (31st). Only 6 days failed to fall to ≤50°. Splitting the month in two, the Average Max./Min./Mean Temperatures were thus: 1st-16th, 69.9°/46.8°/58.4°; 17th-31st, 67.5°/48.0°/57.7°. Even with the warmest 3 days at the end of the month, this still couldn’t balance out the warm weather mid-month. The Maximum Diurnal range was 36.7° (81.7°/45.0°) on the clear 29th, the least being 9.4° (60.4°/51.0°) on the wet 25th.
PRECIPITATION
Continuing the area’s record-dry spring, only 2.00″ fell during May, just 59% of the monthly normal of 3.41″ for this station, per the new 30-year Normals (1991-2020) recently released by the National Centers for Environmental Information. The first week of the month saw 4 days of measurable precipitation then it was basically dry until the 20th as just a few hundredths, at most, were recorded on a few days in between. A potent system brought much-needed rain on the 24th-25th as more than an inch fell. The first 16 days contained 24% (0.48″) of the monthly total, the final 15 days the other 76% (1.52″). Though May was much drier than normal, there was still measurable rain on 14 days but 9 of these being ≤0.10″. The greatest 24-hour amount was the 0.89″ that fell from the early evening of the 24th into the late afternoon of the 25th.
A single day with thunder was observed (25th) and one day of hail (to pea-size) occurred in the early afternoon of the 7th (no thunder was heard).
≥0.25″: 2
≥0.50″: 1
≥1.00″: 0
MISCELLANEOUS
Sky Cover: 9 clear, 15 partly cloudy, and 7 cloudy days.
Barometric Pressure: Average Maximum/Minimum Barometer readings were 30.20″/30.05″, with the Highest Daily Value of 30.43” on the 8th, the Lowest Daily Reading of 29.81” on the 5th.
Relative Humidity: Maximum/Minimum Relative Humidity Averages were 95%/51%, having a Daily Maximum of 99% on the 25th, Daily Minimum of 27% on the 31st.
Dew Point: Average Dew Points were a Maximum/Minimum of 55°/44°, with a Daily Maximum of 62° on the 31st, Daily Minimum of 36° on the 7th.
Wind: Average of 0.9 MPH, with the highest gust reaching 23 MPH from the SSE on the 6th and from the SSW on the 27th.
HAPPY VALLEY WEATHER FORM: MAY 2021
Cover Photo: Sword Dance Peony, 5/29/2021.