MAY 2019 MONTHLY SUMMARY ROCKVILLE 2.8 WNW MARYLAND
by Kevin Shaw, Observer
May 2019 was wetter and warmer than normal. My max temp (76.7°)
was 2.9° above normal and my min temp (59.7°) was even more
significantly 7.9° above normal, resulting in the mean temperature
(68.2°) to be 5.4° above normal. My total precipitation of 6.24″ was
1.97” above the newly computed normal precipitation May value for
my station of 4.27. There were a lot of smaller amounts of daily
precipitation leading to an above normal 13 days with measurable
precipitation, Nine of the 13 days occurred during the first 16
days of the month, including two 4 day streaks of rainfall (1.88”
from May 2-5 and 2.78” from May 10-13).
There were a few cooler than normal days during these wet periods,
particularly from May 12-15 with generally max temps in the 50s
and lows in the 40s (the lowest being 44.3° on the 15th). The rest
of the month had seasonable to seasonably warm temperatures,
highlighted by my first 90° max on the 29th. There were fourteen
80°+ max temps and fifteen 60°+ mins during the month.
There were 13 days with measurable precipitation, highlighted by
the monthly maximum of 1.28″ on the 10th that started our wettest
period of the month through the 13th that was detailed earlier
There were two other notable precipitation days during the month
(1.05” on the 5th and 0.93” on the 28th).
The highest barometric pressure reading of the month of 30.36”
occurred on the 1st. The lowest reading was a rather modest
29.65” on the 29th on the hottest day of the month.
The highest dew point temperature reached during the month was
74° on the 19th and 28th. There were 8 days in May when dew point
temps were 70° or higher, values I consider humid for May.
My warmest air temperature of the month (90.2°) was recorded
during a particularly muggy period on the 29th. The lowest dew point
temperature value was reached on the 14th (2nd coldest day of the
month) when a value of 41° was reached.
May had 11 cloudy days, 13 partly cloudy days, and 7 clear/sunny
days. There were 63 heating degree days and 162 cooling degree
days during the month. There were 5 foggy days, 2 windy days,
and 5 days with thunder.
Daily max/min temperatures varied as they usually do during the
spring. My maximum temperature frequencies included 1 day over
90°, 14 days between 80° and 89°, 9 days between 70° and 79°,
4 days between 60° and 69°, and 3 days between 50° and 59°.
On the minimum temperature frequency side of things, there
were 4 days between 40° and 49°, 12 days between 50° and 59°,
13 days between 60° and 69° and 2 days above 70°. The coldest
daily max temperature was 55.0° on the 13th while the warmest
daily min temp of 71.3° was on the 20th.
The diurnal range daily monthly average was 19.0° (- 3.0°). Our
greatest daily range of temperature was 27.3° on the 2nd
(84.9°-57.6°) and 15th (71.6°-44.3°). We had a total of 11 days
with daily ranges above 20°. Our lowest range of temperature
was 5.2° (66.4°-61.2°) on the 8th. There were 5 total days with
diurnal temperature ranges of less than 10° throughout the
month, all occurring on or before the 13th.
May 2019 was a typical transitional month from spring to
summer, with patterns during the month generally filling the
bill quite well. No problems were experienced with my
weather station during the month thank goodness.
MAY 2019 – ROCKVILLE 2.8 WNW MARYLAND – SUMMARY STATISTICS
Average high temperature 76.7° (+ 2.9°)
Average low temperature 59.7° (+ 7.9°)
Mean temperature 68.2° (+ 5.4°)
Precipitation 6.24″ (+ 1.97”)
Greatest daily amount (date) 1.28″ (10)
Greatest storm total (dates) 2.78” (10-13)
2019 year-to-date precipitation total 20.29″ (+3.57”)
Seasonal snowfall total (final) 26.8″
High temperature for the month (date) 90.2° (29)
Low temperature for the month (date) 44.3° (15)
Highest barometric pressure (date) 30.36” (1)
Lowest barometric pressure (date) 29.65” (29)
Peak wind gust (date/direction): N/A
Heating degree days for the month: 63
Cooling degree days for the month: 162
Greatest diurnal range (date): 27.3° (2,15)
Least diurnal range (date) 5.2° (8)
Number of days:
Partly Cloudy 13
Max temp ≥ 80° 15
Min temp < 50° 4
Min temp =< 32° 0
Precip ≥ 0.01” 13