Monday, June 21, 2026 — Boston rolled into the workweek under clear skies and a cool start, with Logan Airport reporting about 64°F early this morning. Sunshine should stick around into the afternoon with a high near 77°F, but there is a slight chance of showers and thunderstorms between roughly 3:00 PM and 5:00 PM.
Afternoon Storm Chance
The afternoon carries about a 30 percent chance of brief showers or an isolated thunderstorm, with the highest odds over the northeastern suburbs and along the coastline. A west-to-seabreeze boundary may provide just enough spark for a passing storm, but the overall severe-weather threat is low and anything that pops up should be short-lived. Forecasters at the National Weather Service Boston/Norton note west winds this afternoon around 7 to 12 mph.
Monday Night Into Tuesday
Rain ramps up Monday evening and becomes more widespread Monday night into Tuesday, June 22, 2026, with periods of heavy rain possible. The forecast discussion points to roughly a 70-80 percent chance of at least 1 inch of total rainfall across much of southern New England, and a 30-50 percent chance of 2 or more inches, with the highest odds in western Massachusetts and Connecticut. Groundwater and streamflow are currently low, which lowers the risk of more widespread river flooding, but urban ponding and localized street flooding are still on the table. Keep an eye on updates from the NWS Boston/Norton for the latest timing and potential impacts.
Boaters And Commuters
Small Craft Advisories were allowed to expire early this morning, but conditions on the water will turn choppy again Monday night, with gusts near 25 knots and seas approaching 5 feet in spots. Ferry riders and small-boat operators should plan for a rougher ride later on. On land, brief heavy downpours can quickly cut visibility and slow traffic, so build in some extra travel time if you are driving Monday evening.
What To Do
Today is your best bet for outdoor plans in the morning and early afternoon, while the sun is winning the battle. Pack an umbrella or light rain jacket if you will still be out later in the day. For Monday night into Tuesday, try to move sensitive outdoor activities indoors and be ready for temporary puddling in low-lying or poorly drained areas. Stay tuned to official forecasts and local alerts overnight in case the timing or intensity of the rain changes.
