Lexington Weather
Lexington, Massachusetts, USA
- Clear
-
87.1°F / 30.6°C
-
64.4°F
- 88.5°F
-
47%
- Calm, 10-min avg: Calm, gust: None
-
- 10 miles
- 0.00 in
Current Conditions [‒] Current Conditions [+]
87.1°F
30.6°C
Feels like 88.5°F
Hot
Clear
Today: Hi 90 °F
Tonight: Lo 71 °F
Dew Point:
64.4°F
Humidity:
47%
Barometer:
mb
Rain Rate: 0.00 in/hr
Rain Today: 0.00 in
Rain Monday: 0.00 in
Visibility: 10 miles
Wind:
Now: Calm
Avg: Calm
Gusts: 0 mph
Alerts / Advisories [‒] Alerts / Advisories [+]
Forecast [‒] Forecast [+]
NWS Weather Forecast -
Today,
Tonight,
&
Wednesday
through
Monday Night
Issued by:
National Weather Service Boston / Norton, MA
Point Forecast Updated Tue Jun 30, 2026 5:34am EDT
Overview:
- Dangerous prolonged heat and humidity Wed through Sat with afternoon heat indices in the 98 to 112 degree range with little relief at night. Peak of the heat Thu into Fri.
- A cluster of scattered showers and a few t-storms may work into parts of our region very late today and tonight. Activity likely weakening with main severe weather risk to our northwest, but can not rule out a low risk in western MA/CT.
- W/NW flow aloft may bring a low convective/severe weather risk given high Cape/remnant EML Wed-Fri...but limited forcing and cap may keep us mainly dry. Greatest risk for thunderstorms/severe weather potential might wait until Sat July 4th with the actual cold front.
Today:
Mostly Sunny
Hi 90 °F
Mostly sunny, with a high near 90. Southwest wind 2 to 12 mph.
Tonight:
Chance Showers And T-Storms
Lo 71 °F
A chance of showers and thunderstorms after 9pm. Mostly cloudy, with a low around 71. Southwest wind around 13 mph. Chance of precipitation is 40%.
Wednesday:
Chance Showers And T-Storms
Hi 95 °F
A chance of showers and thunderstorms. Partly sunny, with a high near 95. Heat index values as high as 104. Southwest wind around 13 mph, with gusts as high as 23 mph. Chance of precipitation is 30%.
Wednesday Night:
Chance Showers And T-Storms
Lo 75 °F
A chance of showers and thunderstorms. Mostly cloudy, with a low around 75. Heat index values as high as 101. West wind 5 to 10 mph. Chance of precipitation is 30%.
Thursday:
Slight Chance Showers And T-Storms then Sunny
Hi 100 °F
A slight chance of showers and thunderstorms before 8am. Sunny, with a high near 100. West wind 6 to 12 mph. Chance of precipitation is 20%.
Thursday Night:
Clear
Lo 76 °F
Clear, with a low around 76. West wind 5 to 10 mph.
Friday:
Sunny
Hi 98 °F
Sunny, with a high near 98. West wind 6 to 12 mph.
Friday Night:
Mostly Clear
Lo 73 °F
Mostly clear, with a low around 73. West wind 5 to 10 mph.
Independence Day:
Mostly Sunny then Chance Showers And T-Storms
Hi 94 °F
A slight chance of rain showers between noon and 2pm, then a chance of showers and thunderstorms. Mostly sunny, with a high near 94. West wind 5 to 9 mph. Chance of precipitation is 40%.
Saturday Night:
Chance Showers And T-Storms
Lo 71 °F
A chance of showers and thunderstorms before 8pm, then a chance of showers and thunderstorms between 8pm and 10pm, then a slight chance of showers and thunderstorms between 10pm and 1am. Partly cloudy, with a low around 71. West wind around 6 mph. Chance of precipitation is 40%.
Sunday:
Mostly Sunny then Slight Chance Showers And T-Storms
Hi 87 °F
A slight chance of showers and thunderstorms after 5pm. Mostly sunny, with a high near 87. North wind 3 to 7 mph.
Sunday Night:
Partly Cloudy then Slight Chance Rain Showers
Lo 66 °F
A slight chance of rain showers after 5am. Partly cloudy, with a low around 66. East wind around 6 mph.
Monday:
Slight Chance Rain Showers then Slight Chance Showers And T-Storms
Hi 86 °F
A slight chance of rain showers before 2pm, then a slight chance of showers and thunderstorms between 2pm and 4pm, then a chance of showers and thunderstorms. Partly sunny, with a high near 86. East wind 3 to 8 mph. Chance of precipitation is 30%.
Monday Night:
Chance Showers And T-Storms
Lo 66 °F
A chance of showers and thunderstorms. Mostly cloudy, with a low around 66. East wind 2 to 6 mph.
NWS Hourly Forecast -
Today 12pm through Wed 11pm
Issued by:
National Weather Service Boston / Norton, MA
Updated Tue Jun 30, 2026 5:34am EDT
12:00pm
Dew Pt 59°F
SW 6 mphPrecip: 0%
1:00pm
Dew Pt 58°F
SW 8 mphPrecip: 0%
2:00pm
Dew Pt 59°F
S 9 mphPrecip: 1%
3:00pm
Dew Pt 60°F
S 10 mphPrecip: 4%
4:00pm
Dew Pt 62°F
S 12 mphPrecip: 7%
5:00pm
Dew Pt 63°F
Heat Index: 89°F
S 12 mphPrecip: 10%
6:00pm
Dew Pt 64°F
Heat Index: 87°F
S 12 mphPrecip: 13%
7:00pm
Dew Pt 64°F
Heat Index: 85°F
S 12 mphPrecip: 14%
8:00pm
Dew Pt 65°F
Heat Index: 83°F
S 10 mphPrecip: 14%
9:00pm
Dew Pt 64°F
S 12 mphPrecip: 25%
10:00pm
Dew Pt 63°F
SW 12 mphPrecip: 37%
11:00pm
Dew Pt 61°F
SW 13 mphPrecip: 36%
12:00am
Dew Pt 60°F
SW 13 mphPrecip: 35%
1:00am
Dew Pt 60°F
SW 12 mphPrecip: 34%
2:00am
Dew Pt 59°F
SW 12 mphPrecip: 33%
3:00am
Dew Pt 60°F
SW 12 mphPrecip: 31%
4:00am
Dew Pt 60°F
SW 12 mphPrecip: 28%
5:00am
Dew Pt 60°F
SW 10 mphPrecip: 26%
6:00am
Dew Pt 61°F
SW 12 mphPrecip: 22%
7:00am
Dew Pt 61°F
SW 12 mphPrecip: 18%
8:00am
Dew Pt 62°F
W 13 mphPrecip: 14%
9:00am
Dew Pt 64°F
W 13 mphPrecip: 9%
10:00am
Dew Pt 66°F
Heat Index: 85°F
W 13 mphPrecip: 5%
11:00am
Dew Pt 68°F
Heat Index: 89°F
W 13 mphPrecip: 0%
12:00pm
Dew Pt 69°F
Heat Index: 94°F
W 12 mphPrecip: 3%
1:00pm
Dew Pt 70°F
Heat Index: 97°F
W 12 mphPrecip: 5%
2:00pm
Dew Pt 71°F
Heat Index: 100°F
W 12 mphPrecip: 8%
3:00pm
Dew Pt 72°F
Heat Index: 102°F
W 12 mphPrecip: 16%
4:00pm
Dew Pt 72°F
Heat Index: 104°F
W 12 mphPrecip: 23%
5:00pm
Dew Pt 72°F
Heat Index: 102°F
W 12 mphPrecip: 27%
6:00pm
Dew Pt 73°F
Heat Index: 101°F
W 10 mphPrecip: 27%
7:00pm
Dew Pt 73°F
Heat Index: 97°F
SW 9 mphPrecip: 27%
8:00pm
Dew Pt 73°F
Heat Index: 96°F
SW 8 mphPrecip: 27%
9:00pm
Dew Pt 73°F
Heat Index: 92°F
SW 8 mphPrecip: 27%
10:00pm
Dew Pt 72°F
Heat Index: 88°F
SW 8 mphPrecip: 27%
11:00pm
Dew Pt 72°F
Heat Index: 85°F
SW 8 mphPrecip: 27%
FORECAST DISCUSSION
Area Forecast Discussion
for Boston / Norton, MA
000
FXUS61 KBOX 301118
AFDBOX
Area Forecast Discussion
National Weather Service Boston/Norton MA
718 AM EDT Tue Jun 30 2026
.WHAT HAS CHANGED...
The Extreme Heat Watch has been upgraded to an Excessive Heat
Warning for all of southern New England except the south coast and
Berkshires.
&&
.KEY MESSAGES...
- Dangerous prolonged heat and humidity Wed through Sat with
afternoon heat indices in the 98 to 112 degree range with
little relief at night. Peak of the heat Thu into Fri.
- A cluster of scattered showers and a few t-storms may work
into parts of our region very late today and tonight. Activity
likely weakening with main severe weather risk to our northwest,
but can not rule out a low risk in western MA/CT.
- W/NW flow aloft may bring a low convective/severe weather risk
given high Cape/remnant EML Wed-Fri...but limited forcing and cap
may keep us mainly dry. Greatest risk for thunderstorms/severe
weather potential might wait until Sat July 4th with the actual
cold front.
&&
.DISCUSSION...
KEY MESSAGE 1...Dangerous prolonged heat and humidity Wed through
Sat with afternoon heat indices in the 98 to 112 degree range with
little relief at night. Peak of the heat Thu into Fri.
High confidence forecast in dangerous prolonged heat and humidity
Wed through Sat. This continues to be supported by the NAEFS
situational awareness table which indicates many parameters outside
the models climatology. The EFI/shift of tails also indicates both
min/max temperatures on the edge or outside of the models
climatology. 925T peak on Thu and Fri in the +28C to +30C degree
range and that is when we expect the worst of the extreme heat and
humidity.
Today will be very warm and with 850T climbing to +16C/+17C we
should see highs top out in the upper 80s to the lower 90s away from
the south coast. The dangerous heat and humidity starts on Wed when
850T climb to +20C/+21C and expect highs to reach the middle 90s
away from the south coast and possibly upper 90s in a few spots.
This coupled with dewpoints rising to 70+ will result in dangerous
heat and humidity. Heat indices will rise to between 98 and 108
degrees away from the south coast. The worst of the heat and
humidity will likely be in the CT River Valley and Merrimack
Valleys. The extreme heat and humidity peak on Thu and Fri when 850T
reach between +22C and +24C. High temperatures will likely reach
between 97 and 103 away from the south coast and any very localized
sea breezes. Heat indices will reach dangerous levels in the 102 to
113 degree range. It will remain hot and humid on Sat July 4th as
well. While it may be a few degrees lower than Thu/Fri...dangerous
heat and humidity may continue and will be determined by the timing
of a cold front.
Not only will this be a dangerous prolonged heatwave...there will be
little relief at night. Low temperatures will only drop into the
middle 70s in most locations and 75 to 80 degrees in the urban
centers. In fact...Boston may not drop below 80 degrees during the
peak of the heat and humidity!
Given the above...we opted to upgrade most of our region to an
Extreme Heat Warning Wed through Sat. While some areas may
technically not hit warning criteria until Thu and may not on Sat
depending on the timing of the cold front...the overall message
remains the same. We did hold the excessive heat watch along the
Berks and south coast of MA/RI. However...this area will still
experience dangerous heat and humidity but wanted to go with the
warning where our confidence was highest at this point.
KEY MESSAGE 2...A cluster of scattered showers and a few t-storms
may work into parts of our region very late today and tonight.
Activity likely weakening with main severe weather risk to our
northwest, but can not rule out a low risk in western MA/CT.
The other concern for late today and especially tonight is a
shortwave that will be dropping southeast in northwest flow aloft
around the developing ring of fire. Effective shear of 30-40 knots
is favorable for this activity to work into our region...but
instability will be rather marginal. So expect a cluster of
weakening scattered showers and perhaps a few thunderstorms to
impact portions of our region. The greatest risk is across western
MA/CT. The overall severe weather threat is low given the limited
instability in our region...but given northwest flow aloft and
lingering momentum can not rule out a low probability for some
severe weather in western MA/CT. However...currently thinking
greatest risk is northwest of our region.
KEY MESSAGE 3...W/NW flow aloft may bring a low convective/severe
weather risk given high Cape/remnant EML Wed-Fri...but limited
forcing and cap may keep us mainly dry. Greatest risk for
thunderstorms/severe weather potential might wait until Sat July 4th
with the actual cold front.
Anomalous heat and humidity will result in rather high instability
across our region Wed through Fri. In addition...a remnant EML in
northwest flow aloft is present. If somehow we can get a few
thunderstorms going they could quickly become severe even during the
overnight/morning hours. However...lack of overall synoptic forcing
and a mid level cap may keep this risk low but it will still need to
watched. Greatest risk for convection and potentially some severe
weather may wait until Sat July 4th when the cold front/strong
forcing arrives.
&&
.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
Forecaster Confidence Levels...
Low - less than 30 percent.
Moderate - 30 to 60 percent.
High - greater than 60 percent.
12z TAF Update...
Today and tonight...High confidence.
Mainly VFR after areas of low clouds/ground fog mainly across
RI/SE MA by mid morning. Otherwise...will need to watch for a
cluster of weakening scattered showers and perhaps a few
t-storms toward evening and into tonight. Greatest risk for this
activity will be across western MA/CT. S-SW winds 6-13 knots
this afternoon into tonight...but 10-20 knots later tonight
across the Cape/Islands.
Wednesday...High confidence.
Mainly VFR but can not rule out widely scattered
showers/t-storms later Wed into wed night. SW winds 10 to 15
knots with 20 to 25 knot gusts in the afternoon. Strongest of
those gusts toward the Cape/Islands.
KBOS Terminal...High Confidence in TAF. Sea breeze develops by
mid to late morning but should be knocked out and turn S-SW by
mid to late afternoon.
KBDL Terminal...High Confidence in TAF. Showers approach the
termianl 21-23z, with some rumbles of thunder possible around
00z tonight.
Outlook /Wednesday Night through Saturday/...
Wednesday Night: VFR. Breezy. Slight chance SHRA, isolated
TSRA.
Thursday through Friday Night: VFR. Breezy.
Independence Day: VFR. Chance SHRA, chance TSRA.
&&
.MARINE...
Forecaster Confidence Levels...
Low - less than 30 percent.
Moderate - 30 to 60 percent.
High - greater than 60 percent.
Today through Wednesday...High confidence.
Bermuda high pressure will result in a persistent SW flow across our
waters. Despite the inversion enough mixing especially by
Wednesday...particularly near shore should yield SW wind gusts up to
25 knots. In addition....long southwest fetch should build seas to 3-
6 feet across our southern waters. Small craft headlines have been
posted for our southern waters and sounds towards daybreak and
through Wednesday.
Outlook /Wednesday Night through Saturday/...
Wednesday Night: Low risk for Small Craft Advisory winds with
gusts up to 25 kt. Areas of rough seas. Slight chance of rain
showers, isolated thunderstorms.
Thursday through Thursday Night: Low risk for Small Craft
Advisory winds with gusts up to 25 kt. Seas up to 5 ft.
Friday: Winds less than 25 kt.
Friday Night: Winds less than 25 kt. Slight chance of rain
showers.
Independence Day: Winds less than 25 kt. Slight chance of rain
showers, slight chance of thunderstorms.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...Air Quality Alert from 11 AM this morning to 11 PM EDT this
evening for CTZ002.
Extreme Heat Warning from 10 AM Wednesday to 8 PM EDT Saturday
for CTZ002>004.
MA...Extreme Heat Warning from 10 AM Wednesday to 8 PM EDT Saturday
for MAZ003>007-010>019-026.
Extreme Heat Watch from Wednesday morning through Saturday
evening for MAZ002-008-009-020-021.
RI...Extreme Heat Warning from 10 AM Wednesday to 8 PM EDT Saturday
for RIZ001>004.
Extreme Heat Watch from Wednesday morning through Saturday
evening for RIZ005>007.
MARINE...Small Craft Advisory from 8 AM to 11 PM EDT Wednesday for
ANZ231>237.
Small Craft Advisory from 5 AM Wednesday to 4 PM EDT Thursday
for ANZ254>256.
&&
$$
DISCUSSION...Frank
AVIATION...McMinn
MARINE...Frank
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Radar images courtesy Weather Underground / Intellicast.
Satellite [‒] Satellite [+]
Satellite images courtesy Weather Underground / Intellicast.
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UV Forecast [‒] UV Forecast [+]
UV Index forecast from the Environmental Protection Agency
UV Index forecast high for today: 9 Very High
Current (Estimated): 9 Very High
Precipitation [‒] Precipitation [+]
Note: Rain measured automatically by weather station. Rain totals do not necessarily include melted frozen precipitation.
For more accurate, manually measured rain data, see the Local Precip Data page.
0.00 in
Rain Rate (/hr):
0.00 in
Rain Last 60 min:
0.00 in
Rain Today:
0.00 in
Monday:
1.94 in
June:
11.82 in
2026
51.1 in
Season Snow:
Daily Extremes [‒] Daily Extremes [+]
12:34pm
87.4°F
High today:
5:11am
63.7°F
Low today:
12:51pm
84.4°F
High Monday:
5:50am
64.2°F
Low Monday:
11:28am
69.3°F
High dew pt today:
9:36am
67.8°F
High dew pt Monday:
12:26pm
90.9°F
High heat index today:
12:51pm
85.9°F
High heat index Monday:
10:05am
9 mph
Wind gust today:
1:54pm
8 mph
Wind gust Monday:
Sun / Moon [‒] Sun / Moon [+]
First Light:
4:37am
Sunrise:
5:11am
Sunset:
8:26pm
Twilight ends:
9:01pm
Daylight length:
15 hours 15 minutes
Phase:
Waning Gibbous (100%)
Moon set:
5:18am
Moon rise:
9:22pm
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