D.C. March weather outlook: Warm and wet

Celeb Gist

March is poised to tease us with an early surge of springlike warmth and numerous showers to water our gardens. But, by mid-month, it may take a chillier turn.

We are projecting the March average temperature to range from 3 to 5 degrees above the norm of 47.6 degrees in the D.C. area. It would imply conditions similar to 2020, 2021 and 2022 (which had average temperatures of 53.2, 51.2 and 50.4 degrees).

For rainfall, we predict above-normal amounts between 4 to 6 inches compared to the norm of 3.5 inches. Snowfall should be below the norm of 2 inches for the month, but we can’t totally rule out it out during brief colder periods.

Forecast models are simulating a very warm and quite wet first half of the month.

Already, the National Weather Service is predicting that we could receive almost half of our predicted March rainfall during the first week.

However, by around March 15, we may see a shift toward more typical temperatures and less precipitation.

As we head into the second half of the month, atmospheric patterns that meteorologists study, often referred to using abbreviations, may produce a jet stream configuration to support the shift toward cooler weather. The map below, showing the second month weather pattern with the abbreviations labeled, suggests the jet stream may start to dip more into the eastern United States, allowing cooler air to spill south.

Here’s what these abbreviations mean:

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  • The -EPO, the negative phase of the Eastern Pacific Oscillation, and +PNA, the positive phase of the Pacific North American pattern, indicate the jet stream would take a big northward excursion over Alaska and western North America. This tends to favor mild weather in the West but cooler weather in the East as the jet stream dives southward like a seesaw.
  • The -AO, the negative phase of the Arctic Oscillation, and -NAO, the negative phase of the North Atlantic Oscillation, indicate a southward displacement of cold air over the high latitudes of central and eastern North America.

The development of these patterns — a possible response to a disruption of the polar vortex — would stack the deck for colder and stormier weather in the eastern United States. Confidence that they will turn out exactly this way is low, but the fact models have us leaning toward a cooler second half of the month.

February recap

A chilly second half of March would be quite a change from what we’ve been experiencing.

Washington’s average temperature last month was 44.4 degrees, or 4.4 degrees above normal, and marked the seventh-warmest February on record.

Only 1.41 inches of rain and melted snow fell, a deficit of 1.21 inches, marking the 22nd-driest February on record.

We had predicted a milder-than-normal February, but it was even warmer than our expectation. We called for it to be 2 to 4 degrees warmer than normal (compared to the actual of 4.4 degrees). Our predicted rainfall of 2.5 to 3.5 inches was substantially more than what fell, and our snowfall forecast was also too aggressive. We predicted 3 to 6 inches of snow, and only a sad 0.1 inches accumulated.

Over the course of the month, we experienced only four colder-than-normal days.

The month’s lowest high temperature in Washington (as measured at Reagan National Airport) — 42 degrees on Feb. 17 — was the warmest on record, above 1998’s 41 degrees.

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Aside from that, only Dulles International Airport attained temperature records during the month:

  • Dulles’s high of 65 tied the record from 2023.
  • Dulles’s low of 48 was the warmest on record, topping 41 from 2020 and 2023.
  • Dulles’s low of 47 was the warmest on record, topping 46 from 2009 and 2020.
  • Dulles’s high of 69 tied the record from 1977 and 2002.

Year to date

With two months completed in 2024, we can compare its average temperature and precipitation to previous years. Even with the dry February, our wet January has helped the year get off to a wetter-than-normal start:

Temperatures are running considerably warmer than normal, but not as warm as last year at this time, which was the warmest on record through February:

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