• Today

    Apr 18

    68°Lo 41°

    Some sun, then clouds

    Low ragweed pollen levels
    • Grass
      Pollen
      0 - Low
    • Ragweed
      Pollen
      0 - Low
    • Tree
      Pollen
      350 - High
  • Sun

    Apr 19

    57°Lo 39°

    Mostly sunny and cooler

    Low ragweed pollen levels
    • Grass
      Pollen
      0 - Low
    • Ragweed
      Pollen
      0 - Low
    • Tree
      Pollen
      350 - High
    more
  • Mon

    Apr 20

    50°Lo 49°

    Breezy and cooler with rain

    Low ragweed pollen levels
    • Grass
      Pollen
      0 - Low
    • Ragweed
      Pollen
      0 - Low
    • Tree
      Pollen
      350 - High
    more
  • Tue

    Apr 21

    63°Lo 41°

    Warmer with brief showers

    Low ragweed pollen levels
    • Precip
      60%
    • Wind
      Speed
      10 mph
    • Cloud
      Cover
      83%
    more
  • Wed

    Apr 22

    60°Lo 40°

    Mostly cloudy

    Ragweed Pollen Weather
    • Precip
      21%
    • Wind
      Speed
      14 mph
    • Cloud
      Cover
      41%
    more
Next Previous
< Previous 8 hours Next 8 hours >
  Sat
8am
9am 10am 11am 12pm 1pm 2pm 3pm
  8am 9am 10am 11am 12pm 1pm 2pm 3pm
Forecast
Mostly Cloudy
Partly Cloudy
Partly Sunny
Partly Sunny
Partly Sunny
Partly Sunny
Mostly Cloudy
Mostly Cloudy
Temp (°F) 48° 50° 54° 58° 62° 66° 68° 67°
RealFeel® 49° 54° 60° 66° 70° 72° 72° 69°
Humidity 78% 70% 60% 52% 47% 42% 39% 40%
   
  8am 9am 10am 11am 12pm 1pm 2pm 3pm
Rain
 
6%
 
6%
 
6%
 
6%
 
6%
 
6%
 
7%
 
7%
Snow
 
0%
 
0%
 
0%
 
0%
 
0%
 
0%
 
0%
 
0%
Ice
 
0%
 
0%
 
0%
 
0%
 
0%
 
0%
 
0%
 
0%
   
  8am 9am 10am 11am 12pm 1pm 2pm 3pm
Wind (mph) 4 W 5 WNW 5 NW 5 N 6 E 7 SSE 8 S 9 S
UV Index 1 2 3 5 6 6 5 4
Cloud Cover 80% 59% 38% 32% 36% 44% 76% 76%
Dew Point 41° 41° 40° 40° 42° 42° 42° 42°
Middle Grid line 70 F Middle Grid line 65 F Middle Grid line 60 F Middle Grid line 55 F Middle Grid line 50 F Middle Grid line 45 F

Temperature History - Apr 18

more Historical Weather Data >
  Today Normal Record 4/18/2014
High 68° 59° N/A 46°
Low 41° 37° N/A 25°

Sunrise/Sunset

Sunrise / Sunset Illustration

Rises at 6:00 AM with 13:30 of sunlight, then sets at 7:30 PM

Moonrise/Moonset

Astronomy >
Moonrise / Moonset Illustration

Rises at 5:59 AM with 13:35 of moolight, then sets at 7:34 PM

Waltham Weather Report

2015 Boston Marathon Forecast: Rain and Wind in Store for Runners

April 18, 2015; 6:38 AM ET

The 119th Boston Marathon will take place on Monday, April 20, and runners set to take on the historic course will face cool and rainy conditions. more >

Sat. Pollen

Sat. Dust & Dander

Sat. Wind Maps