WEATHER NEWS: D.C. May weather outlook: Near average temperatures, showery
Spring in Washington has been quite uneven with a slightly warmer than normal March and a marginally cooler than normal April.
Our incoming May might bring something right in the middle with a blend of cooler and warmer periods. The weather pattern looks variable enough to deliver healthy springtime showers, too.
We are forecasting the month overall bring near normal temperatures with an average temperature between 65 and 69 degrees (normal is 67.2 degrees). We lean toward near to above normal rainfall between 3.8 and 4.5 inches (normal is 3.94 inches).
We’ve seen a mix of Mays over the last five years: three were cooler than average and two were warmer; likewise, three were wetter than normal and two were drier.
Keep in mind that “near normal” means conditions work out to near average over the entire month. We expect plenty of day-to-day variability ahead with lows in the chilly 40s this weekend and next weekend, but highs often in the warm 70s to even 80s.
The very latest model projections for the next two weeks indicate plenty of variability, but suggest, on balance, near normal temperatures and slightly wetter than normal conditions:
The latest CFS model forecast for the entire month likewise projects average temperatures and above average rainfall:
Probably one of the most significant features to consider in the May outlook is the continuing weak to moderate La Niña in the tropical Pacific Ocean. As noted in an article earlier this week, we are aiming toward a rare third straight year of La Niña. This is shown by the cooler than normal water temperatures along the equator in the Pacific Ocean:
Since 2000, we have only experienced three May months with La Niña conditions. They’ve produced near normal temperatures and wetter than normal conditions as well.
Taken together, it seems like May should avoid extreme temperatures or precipitation for the Washington area with behavior closer to the long-term averages, not unlike March and April.