Lexington Weather

Current Conditions [‒] Current Conditions [+]

69.8°F Colder than last hour.

21.0°C

Muggy

Clear

Overnight: Lo 71 °F

Wednesday: Hi 90 °F

Dew Point: 66.4°F Decreased 0.5°F since last hour.

Humidity: 89% Decreased 1.0% since last hour.

Air Quality Index: 58

Moderate

(Fine Particles)

Barometer: 29.81 in S

1009 mb

Rain Rate: 0.00 in/hr

Rain Today: 0.00 in

Rain Tuesday: 0.08 in

Visibility: 10 miles

Wind:

Now: Calm

Avg: Calm

Gusts: 0 mph

OTHER PERSONAL WEATHER STATIONS

Alerts / Advisories [‒] Alerts / Advisories [+]

Southeast Middlesex County, MA - Heat Advisory
- SEE ALL NEARBY ALERTS -

NWS Weather Forecast -
Overnight, Wednesday, & Wednesday Night through Tuesday

Issued by:
National Weather Service Boston / Norton, MA
Point Forecast Updated Wed May 20, 2026 1:01am EDT

Overview:

- Final day of record warmth today with highs in the 90s away from the immediate coast. Chance for strong to severe thunderstorms by the afternoon with a risk for damaging winds and some hail.

- Cooler temperatures through Memorial Day Weekend. Unsettled weather returns for the weekend with periods of rain possible, but confidence is low.

Heat Advisory

Overnight:

Mostly Clear

Lo 71 °F

Mostly clear, with a low around 71. Southwest wind around 7 mph.

Wednesday:

Mostly Sunny then Chance Rain Showers

Hi 90 °F

A chance of rain showers after 2pm. Mostly sunny. High near 90, with temperatures falling to around 84 in the afternoon. West wind 7 to 13 mph, with gusts as high as 23 mph. Chance of precipitation is 30%.

Wednesday Night:

Mostly Cloudy

Lo 56 °F

Mostly cloudy, with a low around 56. Northwest wind 7 to 12 mph.

Thursday:

Partly Sunny

Hi 68 °F

Partly sunny, with a high near 68. Northwest wind around 8 mph.

Thursday Night:

Partly Cloudy

Lo 47 °F

Partly cloudy, with a low around 47. North wind around 6 mph.

Friday:

Mostly Sunny

Hi 68 °F

Mostly sunny, with a high near 68. East wind 2 to 7 mph.

Friday Night:

Mostly Cloudy then Slight Chance Rain Showers

Lo 49 °F

A slight chance of rain showers after 3am. Mostly cloudy, with a low around 49. Southwest wind 1 to 7 mph.

Saturday:

Chance Rain Showers

Hi 62 °F

A chance of rain showers. Mostly cloudy, with a high near 62. East wind 1 to 7 mph. Chance of precipitation is 40%.

Saturday Night:

Chance Rain Showers

Lo 47 °F

A chance of rain showers. Mostly cloudy, with a low around 47. East wind 2 to 6 mph. Chance of precipitation is 50%.

Sunday:

Chance Rain Showers

Hi 61 °F

A chance of rain showers before 2pm, then a chance of showers and thunderstorms. Mostly cloudy, with a high near 61. East wind 3 to 9 mph. Chance of precipitation is 50%.

Sunday Night:

Chance Showers And T-Storms

Lo 48 °F

Sunday Night: Chance Showers And Thunderstorms

A chance of showers and thunderstorms. Mostly cloudy, with a low around 48. East wind 3 to 7 mph. Chance of precipitation is 50%.

Memorial Day:

Chance Rain Showers

Hi 67 °F

A chance of rain showers before 3pm. Mostly cloudy, with a high near 67. Northeast wind 3 to 7 mph. Chance of precipitation is 40%.

Monday Night:

Slight Chance Rain Showers

Lo 51 °F

A slight chance of rain showers after 8pm. Mostly cloudy, with a low around 51. North wind 2 to 6 mph.

Tuesday:

Slight Chance Rain Showers

Hi 72 °F

A slight chance of rain showers. Partly sunny, with a high near 72. North wind 2 to 6 mph.

FULL FORECAST

NWS Hourly Forecast -
Today 6am through Thu 5pm

Issued by:
National Weather Service Boston / Norton, MA
Updated Wed May 20, 2026 1:01am EDT

6:00am

Mostly Sunny

72°F
Dew Pt 62°F
Wind from SW

SW 7 mph
Precip: 2%

7:00am

Mostly Sunny

74°F
Dew Pt 62°F
Wind from SW

SW 8 mph
Precip: 2%

8:00am

Mostly Sunny

76°F
Dew Pt 64°F
Wind from SW

SW 8 mph
Precip: 2%

9:00am

Sunny

80°F
Dew Pt 64°F
Heat Index: 82°F
Wind from W

W 9 mph
Precip: 2%

10:00am

Sunny

82°F
Dew Pt 65°F
Heat Index: 84°F
Wind from W

W 10 mph
Precip: 2%

11:00am

Sunny

85°F
Dew Pt 66°F
Heat Index: 87°F
Wind from W

W 12 mph
Precip: 4%

12:00pm

Sunny

86°F
Dew Pt 65°F
Heat Index: 88°F
Wind from W

W 13 mph
Precip: 5%

1:00pm

Sunny

88°F
Dew Pt 65°F
Heat Index: 90°F
Wind from W

W 13 mph
Precip: 12%

2:00pm

Chance Rain Showers

87°F
Dew Pt 65°F
Heat Index: 89°F
Wind from W

W 13 mph
Precip: 27%

3:00pm

Chance Rain Showers

86°F
Dew Pt 64°F
Heat Index: 88°F
Wind from W

W 13 mph
Precip: 25%

4:00pm

Slight Chance Rain Showers

85°F
Dew Pt 63°F
Heat Index: 86°F
Wind from W

W 13 mph
Precip: 19%

5:00pm

Slight Chance Rain Showers

84°F
Dew Pt 61°F
Heat Index: 85°F
Wind from W

W 13 mph
Precip: 15%

6:00pm

Partly Cloudy

82°F
Dew Pt 59°F
Heat Index: 83°F
Wind from W

W 12 mph
Precip: 13%

7:00pm

Partly Cloudy

80°F
Dew Pt 57°F
Wind from W

W 10 mph
Precip: 13%

8:00pm

Partly Cloudy

76°F
Dew Pt 55°F
Wind from W

W 9 mph
Precip: 13%

9:00pm

Mostly Cloudy

72°F
Dew Pt 53°F
Wind from W

W 8 mph
Precip: 11%

10:00pm

Mostly Cloudy

70°F
Dew Pt 52°F
Wind from NW

NW 8 mph
Precip: 9%

11:00pm

Mostly Cloudy

67°F
Dew Pt 50°F
Wind from NW

NW 7 mph
Precip: 10%

Thu
12:00am

Mostly Cloudy

65°F
Dew Pt 49°F
Wind from NW

NW 7 mph
Precip: 12%

Thu
1:00am

Mostly Cloudy

65°F
Dew Pt 47°F
Wind from NW

NW 7 mph
Precip: 13%

Thu
2:00am

Mostly Cloudy

63°F
Dew Pt 46°F
Wind from N

N 7 mph
Precip: 8%

Thu
3:00am

Cloudy

61°F
Dew Pt 44°F
Wind from N

N 7 mph
Precip: 7%

Thu
4:00am

Mostly Cloudy

60°F
Dew Pt 42°F
Wind from N

N 7 mph
Precip: 8%

Thu
5:00am

Mostly Cloudy

58°F
Dew Pt 40°F
Wind from N

N 8 mph
Precip: 2%

Thu
6:00am

Mostly Cloudy

57°F
Dew Pt 39°F
Wind from N

N 8 mph
Precip: 0%

Thu
7:00am

Mostly Cloudy

56°F
Dew Pt 38°F
Wind from N

N 8 mph
Precip: 0%

Thu
8:00am

Mostly Cloudy

57°F
Dew Pt 37°F
Wind from N

N 8 mph
Precip: 1%

Thu
9:00am

Partly Sunny

58°F
Dew Pt 37°F
Wind from N

N 7 mph
Precip: 0%

Thu
10:00am

Mostly Cloudy

59°F
Dew Pt 37°F
Wind from N

N 7 mph
Precip: 0%

Thu
11:00am

Mostly Cloudy

60°F
Dew Pt 36°F
Wind from N

N 6 mph
Precip: 0%

Thu
12:00pm

Mostly Cloudy

62°F
Dew Pt 36°F
Wind from N

N 6 mph
Precip: 0%

Thu
1:00pm

Partly Sunny

63°F
Dew Pt 36°F
Wind from NW

NW 6 mph
Precip: 0%

Thu
2:00pm

Partly Sunny

64°F
Dew Pt 35°F
Wind from NW

NW 6 mph
Precip: 0%

Thu
3:00pm

Mostly Sunny

67°F
Dew Pt 32°F
Wind from NW

NW 7 mph
Precip: 0%

Thu
4:00pm

Mostly Sunny

67°F
Dew Pt 31°F
Wind from NW

NW 7 mph
Precip: 0%

Thu
5:00pm

Mostly Sunny

66°F
Dew Pt 31°F
Wind from NW

NW 7 mph
Precip: 0%

VIEW ON NWS WEB SITE

FORECAST DISCUSSION

Area Forecast Discussion
for Boston / Norton, MA

        
000
FXUS61 KBOX 200550
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
150 AM EDT Wed May 20 2026

.WHAT HAS CHANGED...

Signs of potentially salvaging at least one dry weekend day, but
uncertainty remains high. 

&&

.KEY MESSAGES...

- Final day of record warmth today with highs in the 90s away from 
the immediate coast. Chance for strong to severe thunderstorms by 
the afternoon with a risk for damaging winds and some hail. 

- Cooler temperatures through Memorial Day Weekend. Unsettled
  weather returns for the weekend with periods of rain possible,
  but confidence is low.

&&

.DISCUSSION...

KEY MESSAGE 1...Final day of record warmth today with highs in the 
90s away from the immediate coast. Chance for strong to severe 
thunderstorms by the afternoon with a risk for damaging winds and 
some hail. 

One more day with near record temperatures on tap before a drastic 
return to your regularly scheduled May weather. The Heat Advisory 
remains in effect as we see an anomolously warm airmass remaining 
overhead, even as the upper level ridge begins to break down. 
Expecting a mix of sun and diurnal clouds, with westerly downslope 
flow once again contributing to temp maxima in the CT and Merrimack 
valleys. Again, will have to go to the immediate south coast to 
escape the heat but a slight shift in wind direction may bring those 
hot temps closer to the shore than on Tuesday. Relief then arrives 
behind a cold front which is dragged through the region from west to 
east between late morning and this evening. 

This warm and moist airmass (dewpoints climb into the mid 60s) 
produces a decent amount of instability, albeit a bit less than 
Tuesday, around 1,000 J/kg while model soundings show very steep low 
level lapse rates (8.5 C/km). Convergence ahead of the cold front 
will act on this airmass to produce a broken line of relatively 
shallow thunderstorms, limited in depth and organization by poor ML 
lapse rates and marginal 0-6 km bulk shear respectively. Unlike 
Tuesday's more northward severe risk, the best instability and 
resultant t-storm chance looks to be south of the MA pike where some 
damage wind gusts would be the main risk. 

KEY MESSAGE 2...Cooler temperatures through Memorial Day Weekend.
Unsettled weather returns for the weekend with periods of rain 
possible, but confidence is low.

High pressure slowly builds in on Thursday into Friday suppressing 
any rainfall to the south; some guidance wants to keep rain close 
enough to the southern periphery to brush the south coast with rain 
showers the first half of Thursday. Ensemble guidance is a bit more 
bullish on measurable rainfall Thursday morning than the current 
forecast, so that may end up needing to be bumped up in the future. 

Looking to the holiday weekend, as discussed last night the AI 
guidance continues to be dry, with a stronger high suppressing 
unsettled weather just to the south over the mid Atlantic while the 
traditional models are wetter and colder. That being said, the GFS 
continues to also suppress the rain south until Monday while the 
ECMWF has at least slowed the arrival, to perhaps salvage Saturday. 
That being said, ensemble guidance doesn't seem to have caught on to 
any drying ideas, still bullish on rain both days (both the GEFS and 
EPS). The main idea is, there remains a great deal of uncertainty 
with regard to the holiday weekend, but still leaning the forecast 
on a wetter and cooler (50s and low 60s) solution. Temperature-wise, 
after a seasonable Thu/Fri in the upper 60s/low 70s the weekend is 
looking like it may be colder than normal for late May. 

&&

.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
Forecaster Confidence Levels...

Low - less than 30 percent.
Moderate - 30 to 60 percent. 
High - greater than 60 percent.

06Z TAF Update:

Through 12Z...High confidence. Low to moderate confidence for 
ACK CIGS

VFR overnight for most of the terminals. Possible IFR at ACK 
with areas of fog (lower confidence). SW winds 8-15 kts. LLWS
possible for east and southeast terminals overnight. 

Wednesday...Moderate confidence (TSRA chances).  

VFR. Scattered TSRA along and ahead of a cold front in the
afternoon and evening. Given widely scattered nature and
uncertainty in location of TSRA, have included PROB30 groups for
terminals PVD south. WSW winds 8-12 kts with gusts 20-25 kts 
turning NW behind the cold front between 16-00Z. Brief strong 
gusts possible in any thunderstorms.

Wednesday night...Moderate confidence. 

VFR. Some SHRA may linger/expand over southern terminals
overnight into Thursday morning. Light NW winds becoming N. 

Thursday...High confidence. 

VFR. Light winds. 

KBOS...High confidence in TAF.

KBDL...High confidence in TAF.

Outlook /Thursday through Sunday/...

Thursday through Friday: VFR. 

Friday Night through Saturday Night: VFR. Chance SHRA.

Sunday: VFR. Breezy. Chance SHRA, slight chance TSRA.

&&

.MARINE...
Forecaster Confidence Levels...

Low - less than 30 percent. 
Moderate - 30 to 60 percent. 
High - greater than 60 percent.

Through Wednesday: High confidence. 

Small craft advisories remain in effect through 06z Thurs. SW 
winds of 15-25 kt continues this afternoon and overnight 
Seas will also be building to around 4-6 ft, with some 7 
footers possible tonight over the southern waters.

Mainly dry weather prevails through tonight with a few showers
or thunderstorms possible for the northern waters., Some fog may
persist and expand across the southern waters tonight on
increasing southwest winds.

Outlook /Thursday Night through Sunday/...

Wednesday: Low risk for Small Craft Advisory winds with gusts
up to 25 kt. Local rough seas. Slight chance of rain showers. 

Wednesday Night: Winds less than 25 kt. Areas of seas
approaching 5 ft. Chance of rain showers. 

Thursday: Winds less than 25 kt. Seas locally approaching 5 ft.
Slight chance of rain showers. 

Thursday Night through Friday: Winds less than 25 kt. 

Friday Night: Winds less than 25 kt. Chance of rain showers. 

Saturday through Saturday Night: Winds less than 25 kt. Seas
locally approaching 5 ft. Chance of rain showers. 

Sunday: Winds less than 25 kt. Local rough seas. Chance of rain
showers.

&&

.CLIMATE...

Record Highs for Wed May 20...

BOS 91/1996
BDL 99/1996
PVD 95/1996
ORH 91/1903

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...Heat Advisory until 8 PM EDT this evening for CTZ002>004.
MA...Heat Advisory until 8 PM EDT this evening for MAZ003>007-
     010>019-026.
RI...Heat Advisory until 8 PM EDT this evening for RIZ001>004.
MARINE...Small Craft Advisory until 2 AM EDT Thursday for ANZ254>256.

&&

$$

DISCUSSION...BW
AVIATION...BW
MARINE...BW
CLIMATE...BW

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