Lexington Weather
Lexington, Massachusetts, USA
- Clear
-
66.6°F / 19.2°C
-
62.6°F
-
87%
- Calm, 10-min avg: Calm, gust: None
- 10 miles
- 0.00 in
Current Conditions [‒] Current Conditions [+]
66.6°F
19.2°C
Muggy
Clear
Overnight: Lo 66 °F
Thursday: Hi 86 °F
Dew Point:
62.6°F
Humidity:
87%
Barometer:
mb
Rain Rate: 0.00 in/hr
Rain Today: 0.00 in
Rain Wednesday: 0.00 in
Visibility: 10 miles
Wind:
Now: Calm
Avg: Calm
Gusts: 0 mph
Forecast [‒] Forecast [+]
NWS Weather Forecast -
Overnight,
Thursday,
&
Thursday Night
through
Wednesday
Issued by:
National Weather Service Boston / Norton, MA
Point Forecast Updated Thu Aug 20, 2026 2:31am EDT
Overview:
- Unsettled weather returns today with a frontal passage and periods of showers
- Another round of unsettled weather possible for this weekend.
Overnight:
Mostly Clear
Lo 66 °F
Mostly clear, with a low around 66. West wind around 5 mph.
Thursday:
Mostly Sunny then Slight Chance Rain Showers
Hi 86 °F
A slight chance of rain showers after 5pm. Mostly sunny, with a high near 86. West wind 2 to 6 mph. Chance of precipitation is 20%. New rainfall amounts less than a tenth of an inch possible.
Thursday Night:
Rain Showers Likely
Lo 61 °F
Rain showers likely after 8pm. Mostly cloudy, with a low around 61. North wind 2 to 6 mph. Chance of precipitation is 60%. New rainfall amounts between a tenth and quarter of an inch possible.
Friday:
Slight Chance Rain Showers
Hi 79 °F
A slight chance of rain showers. Partly sunny, with a high near 79. Northeast wind 5 to 8 mph. Chance of precipitation is 20%. New rainfall amounts less than a tenth of an inch possible.
Friday Night:
Chance Rain Showers
Lo 61 °F
A chance of rain showers. Mostly cloudy, with a low around 61. Northeast wind 2 to 7 mph. Chance of precipitation is 50%.
Saturday:
Rain Showers
Hi 74 °F
Rain showers before 5pm, then showers and thunderstorms. Cloudy, with a high near 74. Northeast wind around 8 mph. Chance of precipitation is 90%.
Saturday Night:
Showers And T-Storms
Lo 62 °F
Showers and thunderstorms. Mostly cloudy, with a low around 62. Northeast wind 2 to 6 mph. Chance of precipitation is 80%.
Sunday:
Showers And T-Storms Likely
Hi 81 °F
A chance of rain showers before 2pm, then showers and thunderstorms likely. Mostly cloudy, with a high near 81. South wind 2 to 6 mph. Chance of precipitation is 60%.
Sunday Night:
Chance Showers And T-Storms
Lo 63 °F
A chance of showers and thunderstorms before 5am. Mostly cloudy, with a low around 63. Southwest wind around 5 mph. Chance of precipitation is 50%.
Monday:
Mostly Sunny
Hi 82 °F
Mostly sunny, with a high near 82. West wind 3 to 9 mph.
Monday Night:
Mostly Clear
Lo 58 °F
Mostly clear, with a low around 58. West wind around 7 mph.
Tuesday:
Sunny
Hi 81 °F
Sunny, with a high near 81. West wind 5 to 8 mph.
Tuesday Night:
Mostly Clear
Lo 58 °F
Mostly clear, with a low around 58. West wind around 6 mph.
Wednesday:
Sunny
Hi 83 °F
Sunny, with a high near 83. Southwest wind 3 to 7 mph.
NWS Hourly Forecast -
Today 5am through Fri 4pm
Issued by:
National Weather Service Boston / Norton, MA
Updated Thu Aug 20, 2026 2:31am EDT
5:00am
Dew Pt 62°F
W 5 mphPrecip: 0%
6:00am
Dew Pt 61°F
W 5 mphPrecip: 0%
7:00am
Dew Pt 62°F
W 5 mphPrecip: 0%
8:00am
Dew Pt 63°F
NW 6 mphPrecip: 0%
9:00am
Dew Pt 64°F
NW 6 mphPrecip: 0%
10:00am
Dew Pt 64°F
NW 5 mphPrecip: 1%
11:00am
Dew Pt 63°F
Heat Index: 81°F
NW 5 mphPrecip: 1%
12:00pm
Dew Pt 63°F
Heat Index: 83°F
W 3 mphPrecip: 2%
1:00pm
Dew Pt 63°F
Heat Index: 85°F
W 5 mphPrecip: 3%
2:00pm
Dew Pt 63°F
Heat Index: 85°F
W 5 mphPrecip: 3%
3:00pm
Dew Pt 63°F
Heat Index: 85°F
W 5 mphPrecip: 4%
Rain: 0.01 in
4:00pm
Dew Pt 63°F
Heat Index: 85°F
W 2 mphPrecip: 7%
Rain: 0.01 in
5:00pm
Dew Pt 63°F
Heat Index: 82°F
W 2 mphPrecip: 15%
Rain: 0.02 in
6:00pm
Dew Pt 63°F
Heat Index: 81°F
N 2 mphPrecip: 14%
Rain: 0.03 in
7:00pm
Dew Pt 63°F
N 3 mphPrecip: 14%
Rain: 0.03 in
8:00pm
Dew Pt 62°F
NW 2 mphPrecip: 25%
Rain: 0.01 in
9:00pm
Dew Pt 62°F
NW 5 mphPrecip: 46%
Rain: 0.01 in
10:00pm
Dew Pt 62°F
NW 6 mphPrecip: 58%
Rain: 0.01 in
11:00pm
Dew Pt 62°F
NW 5 mphPrecip: 47%
Rain: 0.01 in
12:00am
Dew Pt 62°F
N 5 mphPrecip: 35%
Rain: 0.01 in
1:00am
Dew Pt 61°F
N 2 mphPrecip: 27%
Rain: 0.01 in
2:00am
Dew Pt 61°F
N 2 mphPrecip: 33%
Rain: 0.01 in
3:00am
Dew Pt 60°F
N 2 mphPrecip: 29%
Rain: 0.01 in
4:00am
Dew Pt 60°F
N 5 mphPrecip: 32%
Rain: 0.01 in
5:00am
Dew Pt 60°F
N 5 mphPrecip: 26%
Rain: 0.01 in
6:00am
Dew Pt 59°F
N 6 mphPrecip: 20%
Rain: 0.01 in
7:00am
Dew Pt 60°F
NE 6 mphPrecip: 19%
Rain: 0.01 in
8:00am
Dew Pt 61°F
NE 5 mphPrecip: 18%
9:00am
Dew Pt 62°F
NE 6 mphPrecip: 19%
10:00am
Dew Pt 63°F
NE 7 mphPrecip: 21%
11:00am
Dew Pt 62°F
NE 7 mphPrecip: 22%
12:00pm
Dew Pt 62°F
NE 7 mphPrecip: 21%
1:00pm
Dew Pt 62°F
NE 8 mphPrecip: 19%
2:00pm
Dew Pt 63°F
NE 8 mphPrecip: 17%
3:00pm
Dew Pt 63°F
E 8 mphPrecip: 19%
4:00pm
Dew Pt 63°F
E 8 mphPrecip: 21%
FORECAST DISCUSSION
Area Forecast Discussion
for Boston / Norton, MA
000
FXUS61 KBOX 200759
AFDBOX
Area Forecast Discussion
National Weather Service Boston/Norton MA
359 AM EDT Thu Aug 20 2026
.WHAT HAS CHANGED...
Increased forecast QPF slightly for later today.
&&
.KEY MESSAGES...
- Unsettled weather returns today with a frontal passage and
periods of showers
- Another round of unsettled weather possible for this weekend.
&&
.DISCUSSION...
KEY MESSAGE 1...Unsettled weather returns today with a frontal
passage and periods of showers.
Shortwave disturbances track towards southern New England within SW
flow aloft today. The jet at around 500 mb picks up more towards the
afternoon and, given its placement, provides better ascent. A plume
of above-normal moisture will also advect into the region, with some
guidance having PWAT values up to around 1.7" by the afternoon and
evening hours. With all of these factors together, scattered showers
are expected to move through the region later today into tonight.
Despite this being the day of the event, there are still some
discrepancies between the guidance regarding rainfall totals. The
general consensus is that a front passes through the region late
today into tonight, and with it, scattered showers. Aside from the
GFS, more models have come to agree the higher rainfall totals in
our area will be towards the south coast onto Cape Cod and the
Islands. Totals there range from 0.25" to around an inch, with some
outliers from the CAMs that exceed that. The HREF PMM even has 24
hour totals along the south coast up to 2". This is all most likely
due to these models (and the HREF's members) picking up on the
possible development of showers with more convective
characteristics. HREF probabilities, though, do keep the higher
chances for 1" an hour rates out of southern New England. GFS-based
guidance remains much drier than the other model suites, keeping any
appreciable totals off to our southwest. ECMWF and Canadian
ensembles, though, both agree on around 20 to 50 percent
probabilities for totals to reach or exceed 0.5" towards the south
coast into RI, SE MA, and the Cape, with probes up to 60 percent
towards the Islands in the ECMWF guidance. NAEFS guidance also
tracks the anomalous moisture plume into these same areas, so
rainfall totals reaching at least 0.5" are not out of the question.
Elsewhere in southern New England, totals will be much lower given
the drier air filtering in there.
KEY MESSAGE 2...Another round of unsettled weather possible for this
weekend.
With the drier air coming in behind the front, the interior likely
dries out a bit from any showers going into Friday. Weak low
pressure off the coast of Long Island could track more NE and lead
to scattered showers for SE MA, RI, and the south coast onto Cape
Cod with cyclonic flow keeping conditions moist and
unsettled.
Guidance continues to show the front stalling out somewhere off the
east coast; a much larger shortwave moves in from the Great Lakes
Saturday into Sunday, greatly amplifying the SW flow aloft as well.
Discrepancies regarding the front's placement do remain, but the
most likely track at this time has low pressure tracking right over
southern New England. This would lead to more widespread rainfall
across the region between Saturday and Sunday. NAEFS and other
ensemble guidance once again has us under more anomalous moisture,
so totals that reach around an inch or two remain within the realm
of possibility. Depending on the timing of these waves and low
pressure, thunderstorms could be possible if they can take advantage
of daytime heat.
The front looks to move offshore sometime Monday, allowing for high
pressure to develop in its wake and bring drier weather overall.
&&
.AVIATION /07Z THURSDAY THROUGH MONDAY/...
Forecaster Confidence Levels...
Low - less than 30 percent.
Moderate - 30 to 60 percent.
High - greater than 60 percent.
Through 12z...High confidence.
Mainly VFR with light WSW winds. Patchy MVFR remains possible
for the Cape, and the Islands will likely remain LIFR/IFR for
much of this period, improving as we get closer to sunrise.
Today...High confidence.
VFR. Scattered showers arrive from west to east after 18-20Z
with a few thunderstorms possible. Confidence not high enough to
include TSRA in TAF, but SHRA included as PROB30 for now.
Tonight...Moderate confidence.
VFR with areas of MVFR to IFR towards the Islands. Scattered
showers continue moving east through the overnight period. These
would most likely linger towards the Cape and Islands, along
with SE MA. Winds may briefly pick up slightly following the
frontal passage, with gusts possibly reaching 15 kt at the most.
Friday...Moderate confidence.
Mostly VFR with MVFR/low-end VFR towards the Cape and Islands.
Guidance has shown a possible return of showers as low pressure
passes to our south and east. These would likely impact more
eastern terminals, including into RI. Onshore NE winds 5-10 kt.
KBOS Terminal...High confidence in TAF.
KBDL Terminal...High confidence in TAF.
Outlook /Friday Night through Monday/...
Friday Night: VFR. Chance SHRA, patchy BR.
Saturday: Mainly MVFR, with areas IFR possible. SHRA, isolated
TSRA.
Saturday Night: Mainly VFR, with areas IFR possible. Chance
SHRA, slight chance TSRA.
Sunday: Mainly VFR, with local IFR possible. Chance SHRA,
slight chance TSRA.
Sunday Night: Mainly VFR, with local IFR possible. Slight
chance SHRA, slight chance TSRA.
Monday: VFR. Breezy.
&&
.MARINE...
Forecaster Confidence Levels...
Low - less than 30 percent.
Moderate - 30 to 60 percent.
High - greater than 60 percent.
Through Friday...High confidence.
Light southerly flow today with E flow possible in the afternoon
over the eastern waters. Winds shift more N, then E following
the frontal passage Thursday night, generally to around 15 kt.
Gusts could approach 20 kt over the southern waters heading into
Friday morning. E to NE winds continue into Friday night. Seas
1-3 ft. Showers possible this evening through Friday.
Outlook /Friday Night through Monday/...
Friday Night: Winds less than 25 kt. Chance of rain showers,
patchy fog.
Saturday: Winds less than 25 kt. Seas locally approaching 5 ft.
Rain showers, slight chance of thunderstorms. Local visibility
1 to 3 nm.
Saturday Night: Winds less than 25 kt. Seas up to 5 ft. Rain
showers likely, slight chance of thunderstorms.
Sunday: Winds less than 25 kt. Areas of seas approaching 5 ft.
Chance of rain showers, slight chance of thunderstorms.
Sunday Night: Winds less than 25 kt. Chance of rain showers,
slight chance of thunderstorms.
Monday: Winds less than 25 kt.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...None.
RI...None.
MARINE...None.
&&
$$
DISCUSSION...Hrencecin
AVIATION...Hrencecin
MARINE...Hrencecin
Radar [‒] Radar [+]
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: 8 Very High
Current (Estimated): 0 None
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
Wednesday:
1.63 in
August:
19.29 in
2026
Daily Extremes [‒] Daily Extremes [+]
12:00am
71.2°F
High today:
5:50am
66.6°F
Low today:
1:43pm
85.3°F
High Wednesday:
12:33am
68.5°F
Low Wednesday:
3:51am
63.5°F
High dew pt today:
8:56am
69.4°F
High dew pt Wednesday:
1:45pm
86.9°F
High heat index Wednesday:
None
Wind gust today:
1:22pm
13 mph
Wind gust Wednesday:
Alerts / Advisories [‒] Alerts / Advisories [+]
No alerts/warnings active for Southeast Middlesex County.
Sun / Moon [‒] Sun / Moon [+]
First Light:
5:28am
Sunrise:
5:58am
Sunset:
7:39pm
Twilight ends:
8:09pm
Daylight length:
13 hours 41 minutes
Phase:
First Quarter (53%)
Moon rise:
2:45pm
Moon set:
11:23pm
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