A typical early spring weather pattern is ahead in Richmond over the next couple of weeks. We will have some ups and downs in temperatures, but no phenomenal swings where we would be in the 80s one afternoon and in the 30s the next night.

If you can get past the tree pollen, Wednesday will be a great day to be outside, comfortably into the lower 70s during the afternoon. Thursday will not be quite as warm, as the afternoon and early evening will bring several hours of occasional light rain.

Dry and seasonable weather awaits for the weekend. A weak system will race by to our north on Saturday, but Richmond looks just far enough south to stay out of the rain. 

Temperatures on Friday afternoon will hold in the upper 50s. Then both Saturday and Sunday return to the 60s. Nights this weekend will be around 40 degrees.

After a few showers follow on Monday, the rest of next week looks near or cooler than normal. A batch of cooler air works into Virginia from Canada for a few days, and that may yield one or two nights below freezing.

Pollen and the warming climate

A few nights below freezing at the end of March are not out of the ordinary, but Richmond’s last freeze of the season has been getting earlier as the climate warms.

So far in the 21st century, the average date of the last freeze is April 2, five days earlier than the average over the entire 20th century (April 7).

On the broader scale, early spring is also getting warmer, as the average temperature for the entire month of March has increased about two degrees over those same two time periods.

In effect, Richmond now has the same early spring climate as 20th century Raleigh, and both cities are ranked among the 10 worst areas in the country for allergies by the Asthma and Allergy Foundation of America.

Not surprisingly, warmer weather is showing up earlier in the season — so allergy season starts earlier. Worse, the higher carbon dioxide level of the atmosphere — the main reason for the warming — also impacts the chemistry of pollen-producing plants. In both oak trees and ragweed, the allergenic proteins in the pollen have increased in tandem with carbon dioxide levels.

Astronomical spring arrives

Although meteorological spring started March 1, astronomical spring begins with the equinox this Thursday morning.

Remember that large swings in temperatures are expected during the spring. We do foresee a cooler spell next week, and history has shown that a few cooler spells are coming in April.

As much as we might romanticize spring with sunny days in the 60s, spring is actually an atmospheric battle.

That battle is between the stubborn, slow retreat of cold air back to the polar regions and the warmer, more humid air escaping its annual seclusion in the tropics. 

With each passing day of spring, there is a little bit more daylight and the sun gets slightly higher in the sky. Day by day, more heat is coming into the Northern Hemisphere from the sun.

But the impacts are never in a straight line. Some days, that cold air seems especially stubborn. Other days, you can imagine that the cold air has been defeated for the season. 

Like any long, drawn-out battle, there will be relative periods of quiet and relative periods of turmoil. Sunny days in the 60s are nice, but there is a reason more tornadoes and damaging thunderstorms happen in spring versus any other season. Last week proved a prime example, with more than 1,000 reports of wind damage in storms from Texas to New York.

At least for a few more days, Richmond will have the quieter side of spring.

And before you know it, we can start thinking about summer.