So many months have turned out warmer than normal since 2010 in Berks County and the region — with occasional exceptions — and last month followed suit.
The 67.5-degree average temperature at Reading Regional Airport was 15th warmest May at an official site in Berks County in a database that starts with 1898.
The three 90-degree days last month were not abnormal but the persistency of highs and lows warmer than normal continues. Every day last month after May 8 reached at least 70 degrees.
“This May was largely free of gloomy cool days, which are so common during spring as the nearby ocean is still cold,” said Jeffrey R. Stoudt, Berks weather historian and a retired meteorologist. “The blatant exception was the two days before Mother’s Day when a thick cloud shield and easterly winds kept temperatures close to 50 most of the time.”
The 7th and 8th were the only two days more than 5 degrees cooler than normal, 11 and 6 respectively, the whole month, Stoudt said.
“Longtime residents of Berks and surrounding counties know not to expect steady warmth until very late May or more likely June,” he said. “But every day after Mother’s Day (last month) warmed to at least 70, although a few of the early day lows were still cool. Even so, steady warmth came early this spring.”
The lowest temperature of the month was 37 degrees on the 1st and highest was 94 degrees on the 31st.
Rainy episodes were numerous, with two soaking rains and other episodes of much shorter duration from scatterings of showers and thunderstorms, typical of the warmer half of the year, Stoudt said.
“And, as is typical of warm-season rains, some areas got much more than others as most episodes brought prolonged downpours to a few but only brief or no downpour to most,” he said.
Five months into the year, the airport has recorded 19.53 inches of precipitation, 3.56 above the normal of 15.97.
The current National Weather Service normals are the averages of the years 1991 through 2020. It’s the highest normal for annual precipitation at 45.71 inches and nearly the highest for monthly temperatures, next to the 1931 to 1960 block of years.
May 2021 also had three 90-degree days but much more offsetting cold and still came out in the end very close to that higher normal. That offsetting cold included two abnormally cold days on the 29th and 30th that are nearly without precedent for cold that late in spring.
Such a scenario was repeated in March this year when the 28th contained record cold that, too, was nearly without precedent that far into the spring. That month overall was a few degrees above normal but not warm enough to reach the top 10 list.
In each case, only a couple of dates later in the 124-year record period were that cold.
But, the overall picture is warmth.
Every month but January has at least one entry among its respective 10 warmest from the period starting with 2010. The month with one is June but the other months have more, all the way up to four apiece for February, July and December.
Overall since 2010, 31 months have entered top-10 warmest lists, with in one instance one kicking another off a list.
On the flip side, only four months have entered top-10 coldest lists since 2010: February 2015, Marches in 2014 and 2015, and April 2018.
The months on the coldest and warmest lists are not evenly spread across the decades but are dominated by months from the warm and cold periods in the records.
Summer weather is on holiday at least to start this month. A high pressure system is in control of the conditions in the mid-Atlantic at least for a few more days.
Warmer and more humid conditions are likely by midweek with a cool front kicking off storms followed by a few more pleasant days, according to AccuWeather.
The temperature dipped to 56 degrees officially at the airport on Saturday morning, and lower farther into the countryside.
That low was the chilliest reading since May 29. It was 15 degrees off the date record for cold of 41 degrees in 1977.
The 1970s hold or are tied for date records for cold on 16 of the 30 dates in June.
There are no entries from the 1970s among the 10 warmest of any month. The same can be said for the 1980s.
5.66 inches: rainfall
3.51 inches: normal
3: 90-degree days (year: 3)
High temperature: 94° on the 31st (tie, 2013)
High minimum: 66° on the 14th (tie, 1953 and 1956)
Source: National Weather Service
Totals from the Berks Area Rainfall Networks and other spotter networks:
Douglassville, 7.93 inches; New Morgan, 7.77; Boyertown, 7.45; Birdsboro, 7.36; Knauers, 7.26; Gilbertsville, 7.13; Hopewell Park, 7.01; Frystown, 6.93; Pine Grove, 6.86; Topton, 6.79; Hamburg, 6.60; Boyers Junction, 6.59; Robeson Township (Rock Hollow Woods), 6.55; Adamstown, 6.46; Shartlesville, 6.42; Oley Furnace, 6.40; Lobachsville, 6.35; Elverson north, 6.29; Bally, 6.20; Mohrsville, 6.11; Wernersville, 6.05; Henningsville, 5.93; Mohnton 1, 5.89; Mohnton 2, 5.76; Cornwall Terrace, 5.73; Shoemakersville, 5.62; Mohrsville, 5.51; Lincoln Park, 5.33; Womelsdorf, 5.23; West Reading, 5.19; Vinemont, 5.15; Reading east, 5.14; Spring Ridge, 5.08; Wyomissing Highlands, 5.05; Reading Hillside, 4.94; Shillington, 4.93; Reiffton, 4.79; and Greenfields, 4.74.
Source: Berkshire mont