Zone Forecast Product for Southern New England National Weather Service Boston/Norton MA 103 PM EDT Mon May 18 2026 Forecast keymessages - First multi-day stretch of hot temperatures (in the mid to upper 90s away from the South Coast) with a moderate degree of humidity Tuesday and Wednesday. Near record heat possible. - Isolated thunderstorms possible Tuesday north and west of Interstate 95. Better chances for strong to severe thunderstorms on Wednesday with strong straight line winds the main risk. - Seasonable and dry Thursday and Friday. - Cooler and unsettled weather is possible Memorial Day Weekend, but confidence remains low. Southeast Middlesex MA- Including the city of Cambridge 103 PM EDT Mon May 18 2026 ...HEAT ADVISORY IN EFFECT FROM 11 AM TUESDAY TO 8 PM EDT WEDNESDAY... .THIS AFTERNOON...Sunny. Highs in the upper 70s. East winds 5 to 10 mph with gusts up to 20 mph. .TONIGHT...Mostly clear. Lows in the mid 60s. South winds 5 to 10 mph. .TUESDAY...Mostly sunny. Much warmer with highs in the mid 90s. Southwest winds 10 to 15 mph. Gusts up to 25 mph in the afternoon. .TUESDAY NIGHT...Partly cloudy. Lows in the lower 70s. Southwest winds 5 to 10 mph. Gusts up to 20 mph in the evening. .WEDNESDAY...Showers likely. Hot with highs in the lower 90s. West winds 10 to 15 mph with gusts up to 25 mph. Chance of rain 70 percent. .WEDNESDAY NIGHT...Showers likely. Much cooler with lows in the mid 50s. Chance of rain 70 percent. .THURSDAY...Mostly sunny. Much cooler with highs in the upper 60s. .THURSDAY NIGHT...Mostly clear. Lows in the upper 40s. .FRIDAY...Mostly sunny. Highs in the upper 60s. .FRIDAY NIGHT...Mostly cloudy with a 40 percent chance of showers. Lows in the upper 40s. .SATURDAY AND SATURDAY NIGHT...Showers likely. Highs in the lower 60s. Lows in the upper 40s. Chance of rain 60 percent. .SUNDAY...Mostly cloudy with a 50 percent chance of showers. Highs in the mid 60s.