August 2021 had above average temperatures with significantly above normal precipitation amounts that were concentrated between the 9^th and 28^th. As such there was only one monthly dry spell starting on the 2^nd and carrying through the 8^th. There were numerous wet spells at most other times, most notably from the 9^th-11^th (1.63”) and from the 25^th-28^th when daily thunderstorm action each day totaled 1.07”.

 

My maximum temperature average (85.4°) was 1.1° above normal but my minimum temperature average (69.8°) was 5.4° above normal, resulting in the mean temperature average of 77.6° turning out to be 3.3° above normal. My total precipitation of 6.06″ was 2.89” above the normal August value for my station of 3.17”. There were 15 days with measurable precipitation and 1 day with trace amounts, most all between the 9^th and 28^th.

 

There were four relatively “cool” days in July with max temperatures below 80° (74.4° on the 1st, 77.9° on the 2^nd and 3^rd, and 76.8° on the 7th – only the 1st was wet (0.32”) and the other 3 days were dry). There were only 4 days with minimums below 65 and none below 60. There were 8 days with max temps of 90° or more, topped off by the 94.4° max on the 12^th. There was a significant 5 day period between the 9^th and the 13^th with max temperatures of 90° or more.

 

The monthly maximum daily precipitation amount of 1.02″ was reached on the 10^th with other notable one day  events of .81” on the 13^th, .97” a week later on the 20^th  and .70” a week later on the 27^th when we had our strongest thunderstorm of the month when a greatest PWG of the year was recorded (63 MPH from the W at 1509). Fortunately the power and other accessories did not fail as a result of this storm like what happened with the storm back in July.

 

The extreme barometric pressure readings of the month were rather muted but occurred 3 days of each other. The lowest value of 29.79” on the 31^st as Tropical Storm Ida was approaching the area but rain held off till early on September 1. The highest value of 30.24” occurred only a few days earlier on the 28^th at the end of our prolonged wet spell during much of the month.

 

The highest dew point temperature reached during the month was 80° recorded on the 13^th on a day with a significant thunderstorm later in the day. There were 26 days with dew point values of 70° or greater. The lowest dew point value of 57° occurred on the 2nd during our coolest period of the month. There were only 4 days during the month with dew points in the 50s, all between the 2^nd and the 5^th.

 

August had 10 cloudy, 19 partly cloudy, and 2 clear/sunny days, roughly about normal for August. There were 392 cooling degree days and 0 heating degree days during the month. There were 5 foggy days but only 4 windy days (30+ MPH but only 1 of 40+ MPH but it was a doozy as previously detailed on the 27^th ). Most days during the month had PWG values in the moderate teens (12) and twenties (15) range.

 

My maximum temperature frequencies included 8 days over 90°, 19 days at or over 80°, and 4 days between 70° and 79°. On the minimum temperature frequency side of things, there were 9 days between 60.0° and 69°, and 22 days of 70° or more.  The coolest daily max temperature day was 74.4° on the 1st while the warmest daily min temp day of 74.2° was reached on the 18^th.

 

The diurnal range daily monthly average was 15.6° (- 4.3°). Our greatest daily range of temperature was 23.7° on the 11th (93.9°- 70.2°). We had a total of 6 days with daily ranges above 20°. Our lowest range of temperature was 6.7° (74.4°- 67.7°) on the 1st , our coolest day of the month. There were a total of 6 days with daily ranges under 10° during August.

 

August 2021 was generally wet with only two notable hot periods but still no real extremes save for the very windy thunderstorm on the 27^th. Groundwater reserves are currently in fairly good shape from a wetter August and moderately wet September so far. Extreme heat has stayed away for the most part, keeping lawns and gardens fairly green. The tropics have flared up a bit on occasion, but have been pretty quiet as far as our immediate area goes. We shall see what, if any activity will develop, including, conversely, the coming of cooler fall temperatures.

 

 August 2021 Spreadsheet data file : 

Rockville 2.8 WNW August 2021 Data

 

 

AUGUST 2021 – ROCKVILLE 2.8 WNW MARYLAND – SUMMARY STATISTICS

 

Average high temperature                           85.4° (+1.1°)

Average low temperature                            69.8° (+5.4°)

Mean temperature                                       77.6° (+3.3°)

High temperature for the month (date)       94.4° (12)

Low temperature for the month (date)        60.0°  (2)

 

Precipitation                                                6.06″  (+2.89“)

Greatest daily amount (date)                      1.02″   (10)

Greatest storm total (dates)                        1.63” (9-11)

2021 year-to-date precipitation total         25.08″ (-2.51”)

 

Highest barometric pressure (date)           30.24”  (28)

Lowest barometric pressure (date)            29.79”  (31)

 

Peak wind gust (date/direction):                 63 (27/W)

(USG data across the street)

 

Heating degree days for the month:             0

Cooling degree days for the month:           392

 

Greatest diurnal range (date):                    23.7° (11)

Least diurnal range (date)                            6.7°  (1)

 

Number of days:

 

Fog                                         5

Windy                                     4

Thunder                                  7

Hail                                         0

Cloudy                                  10

Partly Cloudy                        19

Sunny/Clear                            2

Max temp ≥ 90°                      8

Min temp <  65°                      4

Precip ≥ 0.01”                       15