WEATHER FOR BUSINESS

We supply weather data to businesses

Free Weather Plugin

Add this forecast to your website



Local Weather

Franklin 14 Day Long Range Forecast

14 Day weather providing an extended long range forecast outlook for Franklin

Massachusetts, United States Of America

Long range weather outlook for Franklin includes 14 day forecast summary:

The next 14 day outlook for Franklin shows the average daytime maximum temperature will be around 4°C, with a high for the two weeks of 9°C expected on the afternoon of Thursday 27th. The mean minimum temperature will be -4°C, dipping to its lowest on the morning of Monday 3rd at -10°C. The fortnight ahead will have some days seeing a little precipitation and some days with snow. The current forecast indicates Thursday 27th will have the most precipitation with an accumulation of around 11.0mm. On the whole winds are likely to be moderate.

DayLocal TimeDirSpeed/
Gust
Temp/
Feels Like
HumidityPressureCloud AmountPrecip AmountWeather
Sun 23
Feb
01:00

SSW
SSW

6 / 11 mph 27 / 20°F 81% 1019 mb
Low level cloud: 0%
Mid level cloud: 0%
High level cloud: 96%
Most Significant Cloud Type: high
96%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
04:00

WSW
WSW

7 / 12 mph 27 / 19°F 82% 1018 mb
Low level cloud: 0%
Mid level cloud: 96%
High level cloud: 32%
Most Significant Cloud Type: medium
96%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
07:00

WSW
WSW

6 / 11 mph 27 / 20°F 83% 1018 mb
Low level cloud: 0%
Mid level cloud: 100%
High level cloud: 0%
Most Significant Cloud Type: medium
100%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
10:00

W
W

10 / 13 mph 35 / 27°F 63% 1018 mb
Low level cloud: 6%
Mid level cloud: 25%
High level cloud: 0%
Most Significant Cloud Type: medium
40%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
13:00

WNW
WNW

11 / 13 mph 38 / 31°F 63% 1017 mb
Low level cloud: 52%
Mid level cloud: 9%
High level cloud: 0%
Most Significant Cloud Type: low
54%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
16:00

WNW
WNW

8 / 11 mph 37 / 31°F 72% 1017 mb
Low level cloud: 14%
Mid level cloud: 19%
High level cloud: 33%
Most Significant Cloud Type: low
24%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
19:00

W
W

4 / 7 mph 31 / 27°F 92% 1019 mb
Low level cloud: 0%
Mid level cloud: 44%
High level cloud: 98%
Most Significant Cloud Type: medium
47%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
22:00

W
W

4 / 9 mph 29 / 24°F 88% 1019 mb
Low level cloud: 0%
Mid level cloud: 99%
High level cloud: 100%
Most Significant Cloud Type: medium
100%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
Mon 24
Feb
19:00

S
S

9 / 13 mph 36 / 29°F 85% 1015 mb
Low level cloud: 0%
Mid level cloud: 4%
High level cloud: 100%
Most Significant Cloud Type: medium
8%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
22:00

SSW
SSW

12 / 21 mph 36 / 28°F 74% 1013 mb
Low level cloud: 0%
Mid level cloud: 49%
High level cloud: 100%
Most Significant Cloud Type: medium
52%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
Tue 25
Feb
01:00

SSW
SSW

10 / 18 mph 36 / 29°F 80% 1012 mb
Low level cloud: 0%
Mid level cloud: 24%
High level cloud: 100%
Most Significant Cloud Type: medium
28%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
04:00

SSW
SSW

8 / 14 mph 37 / 30°F 87% 1010 mb
Low level cloud: 4%
Mid level cloud: 100%
High level cloud: 100%
Most Significant Cloud Type: medium
100%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
07:00

SSW
SSW

6 / 11 mph 36 / 31°F 93% 1010 mb
Low level cloud: 14%
Mid level cloud: 100%
High level cloud: 100%
Most Significant Cloud Type: medium
100%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
10:00

SSW
SSW

6 / 9 mph 42 / 38°F 81% 1009 mb
Low level cloud: 0%
Mid level cloud: 7%
High level cloud: 100%
Most Significant Cloud Type: medium
11%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
13:00

SSW
SSW

5 / 8 mph 46 / 43°F 79% 1007 mb
Low level cloud: 2%
Mid level cloud: 31%
High level cloud: 100%
Most Significant Cloud Type: medium
39%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
16:00

S
S

5 / 8 mph 46 / 43°F 85% 1005 mb
Low level cloud: 0%
Mid level cloud: 25%
High level cloud: 93%
Most Significant Cloud Type: medium
28%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
19:00

SW
SW

5 / 10 mph 39 / 35°F 94% 1005 mb
Low level cloud: 2%
Mid level cloud: 100%
High level cloud: 100%
Most Significant Cloud Type: medium
100%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
22:00

W
W

6 / 11 mph 38 / 34°F 94% 1003 mb
Low level cloud: 84%
Mid level cloud: 25%
High level cloud: 0%
Most Significant Cloud Type: low
92%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
Wed 26
Feb
01:00

WNW
WNW

9 / 15 mph 37 / 31°F 89% 1004 mb
Low level cloud: 83%
Mid level cloud: 12%
High level cloud: 0%
Most Significant Cloud Type: low
86%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
04:00

WNW
WNW

12 / 18 mph 37 / 29°F 83% 1004 mb
Low level cloud: 99%
Mid level cloud: 8%
High level cloud: 0%
Most Significant Cloud Type: low
100%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
07:00

WNW
WNW

12 / 19 mph 37 / 29°F 77% 1006 mb
Low level cloud: 94%
Mid level cloud: 8%
High level cloud: 0%
Most Significant Cloud Type: low
97%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
10:00

WNW
WNW

12 / 15 mph 42 / 35°F 69% 1008 mb
Low level cloud: 49%
Mid level cloud: 5%
High level cloud: 0%
Most Significant Cloud Type: low
50%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
13:00

NW
NW

11 / 13 mph 45 / 39°F 60% 1009 mb
Low level cloud: 12%
Mid level cloud: 2%
High level cloud: 0%
Most Significant Cloud Type: low
12%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
16:00

WNW
WNW

9 / 10 mph 45 / 40°F 68% 1012 mb
Low level cloud: 21%
Mid level cloud: 2%
High level cloud: 0%
Most Significant Cloud Type: low
21%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
19:00

W
W

5 / 8 mph 37 / 33°F 85% 1014 mb
Low level cloud: 0%
Mid level cloud: 30%
High level cloud: 4%
Most Significant Cloud Type: medium
30%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
22:00

WSW
WSW

5 / 8 mph 35 / 31°F 86% 1015 mb
Low level cloud: 0%
Mid level cloud: 46%
High level cloud: 43%
Most Significant Cloud Type: medium
47%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
Thu 27
Feb
01:00

SSW
SSW

4 / 7 mph 35 / 31°F 86% 1015 mb
Low level cloud: 0%
Mid level cloud: 44%
High level cloud: 87%
Most Significant Cloud Type: medium
47%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
04:00

S
S

4 / 9 mph 35 / 31°F 87% 1013 mb
Low level cloud: 0%
Mid level cloud: 100%
High level cloud: 58%
Most Significant Cloud Type: medium
100%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
07:00

S
S

11 / 18 mph 40 / 33°F 90% 1009 mb
Low level cloud: 94%
Mid level cloud: 100%
High level cloud: 100%
Most Significant Cloud Type: low
100%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
10:00

SSW
SSW

16 / 25 mph 47 / 40°F 84% 1006 mb
Low level cloud: 90%
Mid level cloud: 49%
High level cloud: 100%
Most Significant Cloud Type: low
100%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
13:00

SSW
SSW

13 / 20 mph 48 / 42°F 90% 1003 mb
Low level cloud: 100%
Mid level cloud: 98%
High level cloud: 61%
Most Significant Cloud Type: low
100%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
16:00

SSW
SSW

8 / 12 mph 47 / 42°F 95% 1001 mb
Low level cloud: 95%
Mid level cloud: 98%
High level cloud: 81%
Most Significant Cloud Type: low
100%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
19:00

S
S

5 / 8 mph 45 / 42°F 99% 999 mb
Low level cloud: 95%
Mid level cloud: 98%
High level cloud: 75%
Most Significant Cloud Type: low
100%
Expect 0.1 In of precipitation over the past 3 hours.
0.1 In
22:00

SSW
SSW

5 / 7 mph 44 / 42°F 99% 997 mb
Low level cloud: 99%
Mid level cloud: 100%
High level cloud: 66%
Most Significant Cloud Type: low
100%
Expect 0.2 In of precipitation over the past 3 hours.
0.2 In
Fri 28
Feb
01:00

WSW
WSW

3 / 5 mph 43 / 42°F 99% 994 mb
Low level cloud: 98%
Mid level cloud: 98%
High level cloud: 100%
Most Significant Cloud Type: low
100%
Expect 0.1 In of precipitation over the past 3 hours.
0.1 In
04:00

WNW
WNW

6 / 10 mph 43 / 39°F 95% 992 mb
Low level cloud: 88%
Mid level cloud: 85%
High level cloud: 46%
Most Significant Cloud Type: low
100%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
07:00

WNW
WNW

11 / 15 mph 38 / 30°F 84% 992 mb
Low level cloud: 42%
Mid level cloud: 53%
High level cloud: 100%
Most Significant Cloud Type: low
73%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
10:00

WNW
WNW

15 / 17 mph 39 / 31°F 67% 994 mb
Low level cloud: 3%
Mid level cloud: 4%
High level cloud: 0%
Most Significant Cloud Type: low
4%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
13:00

WNW
WNW

18 / 20 mph 38 / 29°F 60% 996 mb
Low level cloud: 0%
Mid level cloud: 1%
High level cloud: 0%
Most Significant Cloud Type: high
0%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
16:00

WNW
WNW

17 / 19 mph 30 / 18°F 57% 1001 mb
Low level cloud: 1%
Mid level cloud: 0%
High level cloud: 0%
Most Significant Cloud Type: high
0%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
19:00

WNW
WNW

15 / 17 mph 21 / 7°F 57% 1008 mb
Low level cloud: 0%
Mid level cloud: 4%
High level cloud: 78%
Most Significant Cloud Type: medium
7%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
22:00

NW
NW

12 / 14 mph 16 / 3°F 48% 1013 mb
Low level cloud: 0%
Mid level cloud: 11%
High level cloud: 100%
Most Significant Cloud Type: medium
15%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
Sat 01
Mar
01:00

NW
NW

9 / 11 mph 15 / 4°F 39% 1017 mb
Low level cloud: 0%
Mid level cloud: 95%
High level cloud: 9%
Most Significant Cloud Type: medium
95%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
04:00

NNW
NNW

5 / 6 mph 15 / 8°F 35% 1017 mb
Low level cloud: 0%
Mid level cloud: 45%
High level cloud: 20%
Most Significant Cloud Type: medium
46%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
07:00

NE
NE

4 / 5 mph 16 / 10°F 34% 1019 mb
Low level cloud: 0%
Mid level cloud: 100%
High level cloud: 100%
Most Significant Cloud Type: medium
100%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
10:00

E
E

4 / 4 mph 20 / 15°F 30% 1021 mb
Low level cloud: 60%
Mid level cloud: 87%
High level cloud: 0%
Most Significant Cloud Type: low
90%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
13:00

E
E

5 / 6 mph 22 / 15°F 73% 1019 mb
Low level cloud: 92%
Mid level cloud: 75%
High level cloud: 0%
Most Significant Cloud Type: low
100%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
16:00

ENE
ENE

9 / 11 mph 20 / 10°F 84% 1018 mb
Low level cloud: 87%
Mid level cloud: 88%
High level cloud: 0%
Most Significant Cloud Type: low
100%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
19:00

NNE
NNE

7 / 9 mph 20 / 11°F 91% 1019 mb
Low level cloud: 69%
Mid level cloud: 100%
High level cloud: 1%
Most Significant Cloud Type: low
100%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
22:00

N
N

7 / 10 mph 20 / 11°F 90% 1019 mb
Low level cloud: 72%
Mid level cloud: 24%
High level cloud: 14%
Most Significant Cloud Type: low
81%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
DayLocal TimeDirSpeed/
Gust
Temp/
Feels Like
HumidityPressureCloud AmountPrecip AmountWeather
Sun 02
Mar
01:00

SW
SW

13 / 22 mph 38 / 30°F 84% 1009 mb
Low level cloud: 87%
Mid level cloud: 100%
High level cloud: 81%
Most Significant Cloud Type: low
100%
0.0 In
07:00

W
W

12 / 18 mph 37 / 29°F 81% 1003 mb
Low level cloud: 48%
Mid level cloud: 6%
High level cloud: 0%
Most Significant Cloud Type: low
49%
0.0 In
13:00

WNW
WNW

16 / 20 mph 34 / 23°F 49% 1007 mb
Low level cloud: 1%
Mid level cloud: 2%
High level cloud: 0%
Most Significant Cloud Type: low
1%
0.0 In
19:00

WNW
WNW

14 / 21 mph 25 / 13°F 64% 1013 mb
Low level cloud: 48%
Mid level cloud: 6%
High level cloud: 0%
Most Significant Cloud Type: low
50%
0.0 In
Mon 03
Mar
01:00

WNW
WNW

11 / 14 mph 20 / 8°F 62% 1018 mb
Low level cloud: 1%
Mid level cloud: 0%
High level cloud: 0%
Most Significant Cloud Type: high
0%
0.0 In
07:00

NW
NW

11 / 13 mph 16 / 3°F 47% 1018 mb
Low level cloud: 0%
Mid level cloud: 17%
High level cloud: 0%
Most Significant Cloud Type: medium
16%
0.0 In
13:00

NW
NW

10 / 12 mph 34 / 26°F 30% 1016 mb
Low level cloud: 0%
Mid level cloud: 5%
High level cloud: 0%
Most Significant Cloud Type: medium
4%
0.0 In
19:00

NW
NW

5 / 6 mph 38 / 34°F 61% 1022 mb
Low level cloud: 4%
Mid level cloud: 9%
High level cloud: 15%
Most Significant Cloud Type: low
9%
0.0 In
Tue 04
Mar
01:00

SW
SW

13 / 21 mph 35 / 26°F 79% 1009 mb
Low level cloud: 49%
Mid level cloud: 17%
High level cloud: 4%
Most Significant Cloud Type: low
55%
0.0 In
07:00

SSW
SSW

7 / 9 mph 28 / 21°F 55% 1019 mb
Low level cloud: 0%
Mid level cloud: 44%
High level cloud: 32%
Most Significant Cloud Type: medium
45%
0.0 In
13:00

NNW
NNW

11 / 13 mph 39 / 33°F 44% 1011 mb
Low level cloud: 0%
Mid level cloud: 4%
High level cloud: 4%
Most Significant Cloud Type: medium
4%
0.0 In
19:00

SW
SW

8 / 12 mph 37 / 31°F 60% 1013 mb
Low level cloud: 0%
Mid level cloud: 99%
High level cloud: 100%
Most Significant Cloud Type: medium
100%
0.0 In
Wed 05
Mar
01:00

N
N

3 / 3 mph 32 / 30°F 66% 1021 mb
Low level cloud: 0%
Mid level cloud: 6%
High level cloud: 100%
Most Significant Cloud Type: medium
10%
0.0 In
07:00

SSW
SSW

4 / 8 mph 38 / 34°F 90% 1010 mb
Low level cloud: 100%
Mid level cloud: 91%
High level cloud: 17%
Most Significant Cloud Type: low
100%
0.0 In
13:00

S
S

8 / 10 mph 35 / 28°F 60% 1017 mb
Low level cloud: 35%
Mid level cloud: 100%
High level cloud: 100%
Most Significant Cloud Type: medium
100%
0.0 In
19:00

WNW
WNW

2 / 4 mph 42 / 42°F 95% 1010 mb
Low level cloud: 95%
Mid level cloud: 56%
High level cloud: 100%
Most Significant Cloud Type: low
100%
0.0 In
Thu 06
Mar
01:00

S
S

6 / 10 mph 44 / 41°F 99% 998 mb
Low level cloud: 100%
Mid level cloud: 65%
High level cloud: 92%
Most Significant Cloud Type: low
100%
0.5 In
07:00

E
E

6 / 9 mph 39 / 34°F 99% 1000 mb
Low level cloud: 100%
Mid level cloud: 49%
High level cloud: 80%
Most Significant Cloud Type: low
100%
0.7 In
13:00

SSW
SSW

9 / 13 mph 49 / 46°F 98% 981 mb
Low level cloud: 85%
Mid level cloud: 46%
High level cloud: 97%
Most Significant Cloud Type: low
100%
0.6 In
19:00

SW
SW

10 / 16 mph 50 / 46°F 93% 980 mb
Low level cloud: 93%
Mid level cloud: 44%
High level cloud: 20%
Most Significant Cloud Type: low
100%
0.6 In
Fri 07
Mar
01:00

WNW
WNW

16 / 25 mph 25 / 12°F 71% 994 mb
Low level cloud: 8%
Mid level cloud: 0%
High level cloud: 0%
Most Significant Cloud Type: low
8%
0.1 In
07:00

WNW
WNW

16 / 22 mph 24 / 10°F 57% 1005 mb
Low level cloud: 0%
Mid level cloud: 0%
High level cloud: 0%
Most Significant Cloud Type: high
0%
0.1 In
13:00

W
W

19 / 29 mph 24 / 10°F 40% 1003 mb
Low level cloud: 0%
Mid level cloud: 11%
High level cloud: 0%
Most Significant Cloud Type: medium
11%
0.0 In
19:00

W
W

12 / 18 mph 38 / 30°F 59% 1010 mb
Low level cloud: 42%
Mid level cloud: 44%
High level cloud: 4%
Most Significant Cloud Type: low
58%
0.0 In
Sat 08
Mar
01:00

W
W

10 / 15 mph 16 / 3°F 57% 1009 mb
Low level cloud: 40%
Mid level cloud: 34%
High level cloud: 0%
Most Significant Cloud Type: low
52%
0.0 In
07:00

WSW
WSW

7 / 10 mph 37 / 31°F 70% 1010 mb
Low level cloud: 2%
Mid level cloud: 9%
High level cloud: 0%
Most Significant Cloud Type: medium
14%
0.0 In
13:00

WNW
WNW

15 / 22 mph 22 / 8°F 36% 1015 mb
Low level cloud: 50%
Mid level cloud: 10%
High level cloud: 0%
Most Significant Cloud Type: low
53%
0.0 In
19:00

NW
NW

9 / 12 mph 31 / 24°F 59% 1015 mb
Low level cloud: 0%
Mid level cloud: 27%
High level cloud: 0%
Most Significant Cloud Type: medium
28%
0.0 In
Sun 09
Mar
01:00

E
E

2 / 3 mph 22 / 20°F 52% 1018 mb
Low level cloud: 0%
Mid level cloud: 100%
High level cloud: 100%
Most Significant Cloud Type: medium
100%
0.0 In
07:00

WNW
WNW

10 / 13 mph 22 / 11°F 46% 1023 mb
Low level cloud: 0%
Mid level cloud: 0%
High level cloud: 0%
Most Significant Cloud Type: high
0%
0.0 In
13:00

NNE
NNE

13 / 20 mph 23 / 11°F 87% 1011 mb
Low level cloud: 78%
Mid level cloud: 61%
High level cloud: 2%
Most Significant Cloud Type: low
99%
0.3 In
19:00

N
N

7 / 9 mph 26 / 19°F 53% 1027 mb
Low level cloud: 0%
Mid level cloud: 0%
High level cloud: 100%
Most Significant Cloud Type: high
99%
0.0 In
Mon 10
Mar
01:00

WNW
WNW

4 / 7 mph 22 / 15°F 96% 1021 mb
Low level cloud: 1%
Mid level cloud: 5%
High level cloud: 0%
Most Significant Cloud Type: medium
6%
0.1 In
07:00

NE
NE

7 / 9 mph 26 / 18°F 65% 1024 mb
Low level cloud: 62%
Mid level cloud: 100%
High level cloud: 100%
Most Significant Cloud Type: low
100%
0.0 In
13:00

W
W

2 / 4 mph 39 / 38°F 51% 1029 mb
Low level cloud: 0%
Mid level cloud: 0%
High level cloud: 0%
Most Significant Cloud Type: high
0%
0.0 In
19:00

NE
NE

6 / 9 mph 29 / 22°F 94% 1023 mb
Low level cloud: 67%
Mid level cloud: 78%
High level cloud: 100%
Most Significant Cloud Type: low
100%
0.2 In

The day label given represents the local day relative to the local time for the location you are looking at.
(More Info)

Day

This time is corrected for local time zones and where possible for daylight saving times.
(More Info)

Local Time

The wind direction we use on this page is the direction the wind is coming from, given in a 16 point compass format.
(More Info)

Dir

This refers to the sustained average wind speed, normally averaged over a period of 10 minutes for up to 3 hrs.
(More Info)

Speed/
Gust

Temperature from our forecast perspective are fairly well defined, they are what we would expect to measure in a standard meteorological screen (in other words, shaded and well ventilated) at 2 metres above ground level.
(More Info)

Temp/
Feels Like

The relative humidity is the percent of saturation humidity, generally calculated in relation to saturated vapour density.
(More Info)

Humidity

The value given is a total predicted for the previous 3 hrs and includes the time of the forecast being looked at.
(More Info)

Precip Amount

The total amount of cloud as a percentage is derived from looking at cloud cover throughout the atmosphere and estimating how these combine when looked at from the ground.
(More Info)

Cloud Amount

Here we try to capture the feel of the weather as an image – it will never be perfect but is useful for a quick overview.
(More Info)

Weather

When we measure for forecast air pressure we are normally doing this relative to a certain height and most commonly relative to Mean Sea Level.
(More Info)

Pressure