A late-February 82-degree day followed by a stretch of mornings in the frosty 30s? Yep, we’re talking about winter 2023 in central Virginia. After a mild several months (except for that low of 6 degrees in December), it seems like any weather event or temperature is possible. Does this mean we’ll have a scorching summer? Sadly, there is no good way to predict that, says Robert Davis of UVA’s Department of Environmental Sciences. The only sure thing is weather variations, twice a year.
Weather variations
Both spring and fall transition times are when you would expect big changes, Davis says.
The Northern Hemisphere is warming up in spring, but arctic air blasts from the north hit our area and often late winter and early spring nights are very cold. “So we are getting into the season where you can have cold front passages that are strong. There will be several cold days before it warms up again.” Morning frosts can be continual.
Davis says it’s difficult to comment on whether we are seeing greater variability than in the past. “You can’t look at any particular event and say, ‘That is unusual,’” he explains.
Michael McConkey, owner of Edible Landscaping in Afton, agrees that central Virginia weather is up and down, but is sanguine about the struggle involved. “Peach and plum trees here have always been subject to late frost and changes in the weather, mostly because they evolved as arid Persian plants,” he says. Some trees from Japan and China, however, do well here because of climate similarities. Examples are persimmons and jujube, which is a popular fruit in China, brown on the outside and white on the inside, with a sweet apple taste.
“Everyone growing fruits is aware of weather patterns, and they have changed dramatically” for fruit growers, says McConkey.
Ken Bezilla of Southern Exposure Seed Exchange agrees, and says the variations are hardest on fruit growers. Plum trees, often first to flower among trees here, can amount to “the annual sacrifice to the frost gods,” he says.
In general, as the entire planet warms, we would expect less variability overall, Davis says. That may seem counterintuitive. In many parts of the U.S., as the country warms up, the transitional temperature swings are not as great.
The National Oceanic and Atmospheric Administration keeps monthly records of high and low temperature for counties in each state. Notably, Albemarle County was at its warmest ever for the period January to February 2023. According to NOAA, our two-month average was 45.0 degrees Fahrenheit—our warmest-to-date record for those months together, and 9.8 degrees Fahrenheit hotter than the 1901 to 2000 mean of 35.2 degrees Fahrenheit for those months together.
Pam Dawling, a farmer at Twin Oaks Community in Louisa, has been tracking several first appearances of the spring season over a 20-year period. Her data on phenology, the study of cyclic and seasonal natural phenomena, is interesting. Many plants over the past 15 years have made a first appearance in three different months, often March, April, and May. Late frost for the year ranges from April 8 to as late as May 11, with an average date of April 29, Dawling’s records show.
Climatologist and biometeorologist Davis reminds, “I would be very reticent to make anything out of the variations other than this has been a strange winter, and these are the kinds of changes we would often see in the spring.”
Climate change in the region
NASA defines weather as the conditions of the atmosphere over a short period of time, while climate is how the atmosphere “behaves” over relatively long periods of time.
How has our climate changed over time? There are explanations thanks to scientists, farmers, and others who keep track.
The federal Environmental Protection Agency says overall that our state has warmed about 1 degree Fahrenheit in the past century (from a 2017 report). Carbon dioxide levels and other gases that keep heat close to the ground account for higher temperatures, the EPA notes. “Evaporation increases and the atmosphere warms, which increases humidity, average rainfall, and the frequency of heavy rainstorms in many places—but contributes to drought in others.”
The EPA reports that our state can expect more energy usage, because electricity consumption is on track to increase over time because of additional air conditioning. “Seventy years from now, temperatures are likely to rise above 95 degrees Fahrenheit approximately 20 to 40 days per year in the southeastern half of Virginia, compared with about 10 days per year today,” the EPA says.
Another indicator of climate change in our region is that our region’s U.S. Department of Agriculture hardening zone officially changed. SESE’s Bezilla says we have moved from winters of zone 6b (-5 to 0 degrees Fahrenheit/-20.6 to -17.8 degrees Celsius) to zone 7a (0 to 5 degrees Fahrenheit/-17.8 to -15 degrees Celsius) as temperatures rose over time.
Lettuce is now a year-round crop in this area. “Recently I revised our lettuce schedules, partly to take account of hotter weather arriving earlier in the year, and also to even out the harvest,” writes blogger Dawling, author of Sustainable Market Farming: Intensive Vegetable Production on a Few Acres.
In another blog post, the Twin Oaks community farmer recorded observations for the future: “I live and farm in the southeast,” Dawling wrote. “Sea level rises and heavy downpours in our region are already obvious. Dangerously high temperatures, higher humidity, new pests and diseases are moving in. … The growing season is ten days longer than it was in the 1960s.”
For the 48-month period from September 2018 to August 2022, Albemarle County was at its warmest, with a value of 47.0 degrees Fahrenheit compared with a value for the mean of 43.5 degrees Fahrenheit for the same 1901 to 2000 period, per the NOAA charts. (This tied for warmest with the same period ending in 2020.)
Effects on agriculture and animals
Local growers work hard to protect their fragile plants. For example, Crown Orchard has installed wind turbines at its farms, and Barboursville Vineyard has put in wind machinery to keep cooler air from settling onto its future produce.
Sometimes the fight can seem futile, however.
Susan Smith Ordel, a longtime local gardener, says, “I have noticed just being outside all of the time, the nights in August would cool off. You felt watering was doing some good. Now the plants don’t get a break” from evaporation.
Adaptation is a solution. Crown Orchards is taking advantage of more sun with solar panel arrays near Carter Mountain Orchard, on the rooftop of Chiles Peach Orchard in Crozet, and at the production facility in Covesville, the company’s website notes.
Southern Exposure Seed Exchange creates huge trial tracts each year to see what grows best, and which plants and seeds do best in particular in Virginia and surrounding states. SESE’s trial fields, based in Mineral, are the launching pad for the 28 new varieties the exchange added to its 2023 listings. Among the new winners are Okinawa Pink okra (from Japan), Greek pepperoncini peppers, Gulag Stars kale (from Russia), and Florida conch southern pea. (The SESE website has a category that central Virginia gardeners might do well to peruse: “Especially well-suited to the Southeast.”)
Spinach is a crop that has become too tender for our hot summers. Bezilla says some spinach varieties make for good planting over the winter.
McConkey says native trees like mulberries and pawpaws do well. Still, many shoppers love their peach, pear, and plum trees, which can be marginal here.
Ordel planted five camellias in her yard that she wouldn’t have touched 10 or 15 years ago, she says. “Usually you think of camellias as being in the deep South, in South Carolina, Georgia, and Alabama, but now we’re starting to be able to see them bloom and thrive here.”
She does mourn a favorite plant that just can’t hack our climate. “Now it is clear we can’t plant hydrangea macrophylla any more” (also called French hydrangea). “The hydrangeas have to have cool nights, and I still have clients asking me for the beautiful blue blooms. We’ve had later frosts, and if the buds don’t get nipped in the spring, the early hot weather either deforms the blooms or keeps them from being realized.”
Winemaker, vineyard, and tasting room owner Michael Shaps can speak to the vagaries of wine production, both with his grapes here at Michael Shaps Wineworks and in Meursault, France, in the Burgundy region. Fortunately, Virginia’s changes are not as dramatic as those he has witnessed in France.
“What I have really noticed in Virginia is the intensity of storms we have seen over the past few years,” Shaps says. The amount of rain and the intensity of storms has been much more severe than in the past 30 years in general, he says. A big fear is hail damage, which has happened at times, but he says is “not significant” for his Virginia vines. The pattern of weather lately has been Gulf of Mexico moisture from the south, rather than storms flowing across the country from the west, he says.
Deforestation, which removes trees that modulate how fast storms move over an area, can also increase storm intensity, Bezilla explains.
On top of that, farmers and growers need to worry about earlier appearances of pests. For example, Dawling’s phenology chart tracks when the harlequin bugs first come out to sip the sap from kale, cabbage, and collards, which has been as early as March 13 for the years 2006 to 2020.
Any year that is warmer earlier may result in extra generations of insects, Bezilla says. This can be detrimental when pests multiply, but also helpful if there are additional pollinating bees.
Human hardship
There is proof that weather changes also affect human health. Davis and Kyle Enfield, M.D., who works in the Division of Pulmonary and Critical Care at the UVA School of Medicine, examined 19 years of daily admissions at UVA’s hospital for respiratory reasons. For the first time ever, a measurement called the Acclimatization Thermal Strain Index was applied to human disease. ATSI measures strain on the lung system.
Davis and Enfield learned that there is a definite relationship between seasonal strain stemming from warm, humid air changing to cold, dry air and hospital admissions, on a seasonal scale and on a weekly time scale. Their work, published in 2017 in the International Journal of Biometeorology, showed the adjustment from cold air to warm air didn’t affect health as clearly as during the fall season.
The EPA 2017 report notes that warmer temperatures can also increase the formation of ground-level ozone, a major component of smog. Because ozone can aggravate lung diseases such as asthma, and increases the risk of premature death from heart or lung disease, the EPA and the Virginia Department of Environmental Quality have been working to reduce ozone concentrations, which will become more difficult with warming trends.
In 2022, Ordel had her first bout of heat exhaustion because she cannot stay hydrated no matter how much water she drinks. “Even starting early, now I have found that past 2pm it’s just too brutally hot.”
Respiratory difficulties and heat emergencies aside, living with weather changes can cause higher expenses, as air conditioning in longer summers and heating in longer springs extends energy needs.
Ordel’s family depends on a wood stove in their Keswick home. “It was like clockwork for decades that we would start all-day wood in mid-October and go until tax day,” she says. “Now we start full-time fires in the full month of November and go until mid-May, and that’s consistently true now for about five years. It is clear to me there is climate change.”
