Gaithersburg 2 WNW Maryland – November 2015 climate summary

by Kevin Shaw, Observer in charge

Average high temperature 60.1° (+ 4.9°) Average low temperature 41.6° (+ 6.9°) Mean temperature 50.9° (+ 5.9°) Precipitation 2.46″ (- 1.36″) Greatest daily amount (date) 0.60″ (9)
Year to date precipitation 38.15″ (- 3.32″) Snowfall 0.0″ (- 1.0″) High temperature for the month (date) 78° (6)
Low temperature for the month (date) 30° (21,23) Highest barometric pressure (date) 30.80″ (26)
Lowest barometric pressure (date) 29.59″ (12)
Peak wind gust (date/direction): 23 (18/SW)
Heating degree days for the month: 429
Cooling degree days for the month: 5
Greatest diurnal range (date): 31.9° (16)
Least diurnal range (date) 4.3° (30)

Fog days: 3
Thunder days: 0
Sunny/clear days: 10 Partly Cloudy days: 8 Cloudy days: 12

Days with measurable precipitation (=>.01″) = 11
Days with maximum temperatures of 70 or more = 3
Days with minimum temperatures of 32 or less = 4


One of the most unusual records was set on November 2. I don’t have a long record of this since I only have had wind records back to November 2009 but since that time November 2, 2015 was the first day I ever had where I recorded no wind all day. I don’t really keep records of that, but I don’t ever remember doing that. On a more traditional note, my average mean temperature of 50.9° is my warmest ever November monthly average temperature, surpassing the old record of 50.5° back in 1985. Contributing to this statistic was data for my average maximum temp of 60.1° (4th highest ever) and my average minimum temp of 41.6° (2nd highest ever). The 2.46″ total precipitation for November was the 11th driest (tied with 1991) ever. The 6th of this month was the most notable day of November in that it set 3 separate records (78° record high, 62° record high min, and 0.60″ record daily precipitation for that date, along with the wettest day of the month). The only other record was the 54° temperature on the 19th, another record high minimum temperature. No monthly snow was the 13th time that has occurred in November.

November 2015 was quite above normal statistically in temperature and below normal in precipitation. Out of 37 Novembers in my period of record (POR) I have had 8 such months – dry and warm that is. Precipitation fell fairly evenly throughout the entire month, with a bit of a minimum between the 11th and the 27th when only 0.48″ fell, or about about 15% of the month’s precipitation. Our wettest period from the 9th- 10th of 1.04″ was about 42% of the monthly total. 11 days of measurable rainfall for the month was a bit above the normal amount of 9.5.

The average maximum temperature for the month was 60.1° (+4.9°), the average minimum temperature was 41.6° (+ 6.9°). The resultant mean average temperature for the month was 51.9° (+ 5.9°). There were a few warm max temperatures during the first week or so into the low-mid 70s but nothing really spectacular. Persistent warmth with a lack of any real cold snaps kept the averages well above normal.

The month’s total precipitation amount of 2.46″ was 1.36″ below the normal November amount of 3.82″. It tied 1991 for the 11th driest November in my 37 year period of record (POR). The year to date (YTD) precipitation total of 38.15″ now puts us 3.32″ below the normal YTD average amount for this time of year of 41.47″.

The monthly highest barometric pressure reading of 30.80″ on the 26th was quite significant and highest reading since the year’s high (so far) of 30.89″ that was recorded back on February 28. So this reading will probably turn out the 2nd highest value for the year.. It occurred towards the end of an 8 day dry spell, longest one of the month. Temperatures during this spell started out cold, but warmed towards the end and especially on the 26th. The lowest pressure reading of the month was a more modest 29.59″ on the 12th, right at the end of the generally wet period during the first 12 days of the month. Average barometric pressure for the month was 30.21″, within .01″ if you averaged the two extreme values (30.80″ and 29.59″). So far with eight months study under my belt, this relationship has shown up as the same in March, 0.06″ difference in April, and 0.02″ in May and June, 0.005″ in July, 0.01″in August, 0.04″ in September, 0.06″ in October and 0.01″ in November. These values continue to look very promising for developing a strong relationship there. Almost at the end of the year and the end of the study, so conclusions will be forthcoming next month.

The distribution of 10 sunny, 8 partly cloudy and 12 cloudy days did not correlate well with the below normal monthly precipitation 2.46″ amount.

There were 429 heating degree days and 5 cooling degree days. There were 3 days with fog observed and no thunder days. The peak wind gust during November was a modest 23 MPH out of the SW on the backside of the retreating biggest rain system of the month on the 9th and 10th. This is the fourth month in a row with a peak wind gust value of 23 MPH. Prior to that I had a 3 month streak with a peak wind gust value of 20 MPH.

My maximum temperature frequencies included 3 days between 70°and 79°, 13 days from 60° to 69°, 11 days between 50° and 59°, and 3 days between 40° and 49°, On the minimum temperature frequency side of things, there were 15 days between 30° and 39°, 10 days between 40°-49°, 4 days between 50° and 59° and 1 day with minimums of 60° or greater.

The diurnal range average was a bit below normal (18.5° vs the normal 20.5°). The max daily range of 31.9° occurred on the 16th on the peak of the second longest dry spell of the month between the 13th and the 18th. The lowest daily temperature range of 4.3° occurred on the last day of the month, during our mini 3 day wet period that closed out the month. We had just the one
day on the 30th with a diurnal range less than 10° amd just 3 days with ranges of 30° or more but had 9 additional days with ranges of 20° or more, distributed fairly evenly through the month.

November 2015 had a few more notable extremes than October did, but mostly on the warm temperature side. There still has been a lack of really cold air so far this season as we head into December. It looks like another El Nino winter
ahead of us, which could mean just about anything for our area. Other factors are involved that could cause great fluctuations in our winter weather. Stay tuned
in a few weeks for the December report as we head into the winter and the holiday season and also the new year of 2016!

This email has been checked for viruses by Avast antivirus software.

This entry was posted in Uncategorized. Bookmark the permalink.

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s