March 2018 Monthly summary and statistics for the NJWO Blog – Kevin Shaw, Rockville 2.8 WNW Maryland Observer


By Kevin Shaw, Observer in Charge

March 2018 turned the tables on our really warm February, so much so that I actually averaged colder in March by about 3° than February. While we were drier in March, because of the colder temps we got more snow in March than in February. There were only 12 days in February with minimum temperatures at or below freezing, in March there were 22, including a streak of 19 straight (from March 8 through March 26 – using rounded values to the nearest degree) While we had a grand snowfall total of 4.5”, 3.4” of it fell on the first day of spring on March 21, along with our coldest maximum temperature for the month of 33.1°. Precipitation was significantly below normal at the three major Baltimore/Washington airports. Our biggest storm was associated with the biggest snowfall, as 1.01” fell on the 2 day period (March 20-21). There were only 8 days with measurable precipitation, assuredly somewhat below normal I am sure, with an additional 3 days with trace amounts. The highest barometric pressure reading of the month (30.72″) on the 26th was in the middle of our month’s longest dry streak. The lowest barometric pressure reading of the month (29.45″) occurred on the 1st day of the month, during a 2 day stormy period kind of leftover from late February. The month was mostly partly cloudy (16 days) to go along with the subnormal precipitation, with only 5 clear days logged along with 10 cloudy days. The month was generally cool to cold, save for the brief warm spell at the end of the month, which followed our highest barometric pressure days.

There were 773 heating degree days (HDD) and 0 cooling degree days (CDD) during the month. There were 5 foggy days, 7 days with snow (including trace amounts), and 10 windy days. That is a subjective category with no real data values to back it, just based on my email daily weather posts that are also posted on There were 2 days with sleet and 1 day with glaze (both occurred on the 21st mixed in with our biggest monthly snowfall during the month with sleet also recorded on the 20th, the day before) .

Daily max/min temperatures varied a bit less widely throughout the month. My maximum temperature frequencies included 2 days over 70°, 0 days between 60° and 69°, 5 days between 50° and 59°, 22 days between 40° and 49°, and 2 days between 30° and 39°.. On the minimum temperature frequency side of things, 7 days between 20° and 29°, 20 days between 30° and 39°, and 4 days between 40° and 49°. The coldest daily max temperature was 33.1° on the snowy 21st (coldest min however, was 26.8° on the 11th) and the warmest daily min temp was 47.1° on that warmest day on the 29th (74.1°).

The diurnal range daily monthly average was 15.3°. Our greatest daily range of temperature was 28.6°, formed from a high of 71.8° and low of 43.2° on the 30th during the brief warm spell at the end of the month.. We only had an additional 4 days with daily ranges above 20°. Our lowest range of temperature was 3.3° on our snowiest (3.4”) day of the month (21st) when our readings (33.1° and 29.8°) teetered around the freezing mark. There were only 2 other days with diurnal temperature ranges less than 10.0°, a decrease of 6 over last month. The distribution of the low diurnal range days was spread randomly throughout the month whereas the highest diurnal range days occurred around the middle and end of the month.

With yet another month to study the most recent instrument changes made in mid-August, data appears to be stable and an overall data quality improvement success. I am still constantly checking on my data quality frequently along with some of my Maryland weather cohorts. I have been swapping out gauges when frozen precipitation occurs to allow for casual, comfortable melting inside my apartment. Despite the late blooming spring, I think the snow measuring season is finally behind us and I need to bring my snowboard in. My rain gauge has been restored to fully operational mode, with both the inner and outer cylinders and the funnel in place. I also have continued as close to daily (as time allows) GLOBE Cloud observations, complete with submission of sky pictures at the time of the observation, usually timed with the passage of satellites and also solar noon right now with the time change about 70 minutes past actual EDT noon. Please ask me any questions you want at any time about my station setup and/or my data through any means available to you.


Average high temperature 47.7°

Average low temperature 32.4°

Mean temperature 40.1°

Precipitation 1.62″

Greatest daily amount (date) 0.69″ (20)

Snow 4.5″

Greatest daily amount (date) 3.4” (21)

2018 year-to-date precipitation total 8.25″

Seasonal snowfall total as of 2/28/2018 11.7″

High temperature for the month (date) 74.3° (29)

Low temperature for the month (date) 26.8° (11)

Highest barometric pressure (date) 30.72” (26)

Lowest barometric pressure (date) 29.45” (1)

Peak wind gust (date/direction): N/A

Heating degree days for the month: 773

Cooling degree days for the month: 0

Greatest diurnal range (date): 28.6° (30)

Least diurnal range (date) 3.3° (21)

Number of days:

Fog 5

Windy 10

Snow 7

Cloudy 10

Partly Cloudy 16

Sunny/Clear 5

Max temp ≥ 70° 2

Min temp ≤ 32° 22

Max temp ≤ 32° 0

Precip ≥ 0.01” 8


About dabourphoto

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