Weather2 on Twitter Weather2 on Facebook Weather2 on YouTube Weather2 blog

WEATHER FOR BUSINESS

We supply weather data to businesses

Free Weather Plugin

Add this forecast to your website



Local Weather

Holcombe Brook 14 Day Long Range Forecast

14 Day weather providing an extended long range forecast outlook for Holcombe Brook

Lancashire, United Kingdom

Long range weather outlook for Holcombe Brook includes 14 day forecast summary:

The next 14 day outlook for Holcombe Brook shows the average daytime maximum temperature will be around 9°C, with a high for the two weeks of 13°C expected on the afternoon of Friday 16th. The mean minimum temperature will be 5°C, dipping to its lowest on the morning of Wednesday 21st at 3°C. Expect the next 14 days remain predominantly dry. On the whole winds are likely to be moderate.

DayLocal TimeDirSpeed/
Gust
Temp/
Feels Like
HumidityPressureCloud AmountPrecip AmountWeather
Thu 15
Nov
18:00

S
S

10 / 12 mph 54 / 51°F 93% 1018 mb
Low level cloud: 81%
Mid level cloud: 18%
High level cloud: 4%
Most Significant Cloud Type: low
87%
Expect 0.00 In of precipitation over the past 3 hours.
0.00 In
21:00

S
S

7 / 11 mph 52 / 50°F 96% 1019 mb
Low level cloud: 84%
Mid level cloud: 6%
High level cloud: 1%
Most Significant Cloud Type: low
85%
Expect 0.00 In of precipitation over the past 3 hours.
0.00 In
Fri 16
Nov
00:00

S
S

6 / 10 mph 51 / 49°F 98% 1021 mb
Low level cloud: 78%
Mid level cloud: 6%
High level cloud: 0%
Most Significant Cloud Type: low
100%
Expect 0.00 In of precipitation over the past 3 hours.
0.00 In
03:00

SE
SE

5 / 9 mph 49 / 47°F 98% 1022 mb
Low level cloud: 57%
Mid level cloud: 5%
High level cloud: 0%
Most Significant Cloud Type: low
100%
Expect 0.00 In of precipitation over the past 3 hours.
0.00 In
06:00

ESE
ESE

5 / 10 mph 48 / 46°F 97% 1022 mb
Low level cloud: 37%
Mid level cloud: 5%
High level cloud: 0%
Most Significant Cloud Type: low
38%
Expect 0.00 In of precipitation over the past 3 hours.
0.00 In
09:00

SE
SE

6 / 9 mph 51 / 49°F 97% 1024 mb
Low level cloud: 70%
Mid level cloud: 4%
High level cloud: 0%
Most Significant Cloud Type: low
71%
Expect 0.00 In of precipitation over the past 3 hours.
0.00 In
12:00

SE
SE

8 / 11 mph 54 / 52°F 86% 1024 mb
Low level cloud: 50%
Mid level cloud: 2%
High level cloud: 0%
Most Significant Cloud Type: low
50%
Expect 0.00 In of precipitation over the past 3 hours.
0.00 In
15:00

SE
SE

7 / 10 mph 56 / 54°F 85% 1024 mb
Low level cloud: 45%
Mid level cloud: 0%
High level cloud: 0%
Most Significant Cloud Type: low
45%
Expect 0.00 In of precipitation over the past 3 hours.
0.00 In
18:00

ESE
ESE

8 / 9 mph 55 / 53°F 91% 1025 mb
Low level cloud: 29%
Mid level cloud: 0%
High level cloud: 0%
Most Significant Cloud Type: low
29%
Expect 0.00 In of precipitation over the past 3 hours.
0.00 In
21:00

ESE
ESE

9 / 13 mph 52 / 49°F 89% 1025 mb
Low level cloud: 35%
Mid level cloud: 0%
High level cloud: 0%
Most Significant Cloud Type: low
34%
Expect 0.00 In of precipitation over the past 3 hours.
0.00 In
Sat 17
Nov
00:00

ESE
ESE

9 / 16 mph 48 / 44°F 85% 1026 mb
Low level cloud: 11%
Mid level cloud: 0%
High level cloud: 0%
Most Significant Cloud Type: low
11%
Expect 0.00 In of precipitation over the past 3 hours.
0.00 In
03:00

E
E

9 / 15 mph 46 / 41°F 91% 1026 mb
Low level cloud: 40%
Mid level cloud: 0%
High level cloud: 0%
Most Significant Cloud Type: low
40%
Expect 0.00 In of precipitation over the past 3 hours.
0.00 In
06:00

E
E

11 / 19 mph 45 / 39°F 88% 1026 mb
Low level cloud: 28%
Mid level cloud: 0%
High level cloud: 0%
Most Significant Cloud Type: low
28%
Expect 0.00 In of precipitation over the past 3 hours.
0.00 In
09:00

E
E

12 / 17 mph 48 / 42°F 81% 1027 mb
Low level cloud: 0%
Mid level cloud: 4%
High level cloud: 0%
Most Significant Cloud Type: medium
3%
Expect 0.00 In of precipitation over the past 3 hours.
0.00 In
12:00

ESE
ESE

13 / 20 mph 51 / 46°F 63% 1027 mb
Low level cloud: 0%
Mid level cloud: 0%
High level cloud: 0%
Most Significant Cloud Type: high
0%
Expect 0.00 In of precipitation over the past 3 hours.
0.00 In
15:00

E
E

13 / 17 mph 52 / 48°F 66% 1027 mb
Low level cloud: 0%
Mid level cloud: 0%
High level cloud: 0%
Most Significant Cloud Type: high
0%
Expect 0.00 In of precipitation over the past 3 hours.
0.00 In
18:00

E
E

13 / 15 mph 52 / 48°F 73% 1028 mb
Low level cloud: 0%
Mid level cloud: 0%
High level cloud: 0%
Most Significant Cloud Type: high
0%
Expect 0.00 In of precipitation over the past 3 hours.
0.00 In
21:00

ESE
ESE

13 / 16 mph 50 / 45°F 72% 1028 mb
Low level cloud: 0%
Mid level cloud: 0%
High level cloud: 0%
Most Significant Cloud Type: high
0%
Expect 0.00 In of precipitation over the past 3 hours.
0.00 In
Sun 18
Nov
00:00

E
E

13 / 16 mph 48 / 42°F 75% 1029 mb
Low level cloud: 0%
Mid level cloud: 0%
High level cloud: 0%
Most Significant Cloud Type: high
0%
Expect 0.00 In of precipitation over the past 3 hours.
0.00 In
03:00

E
E

12 / 18 mph 46 / 40°F 77% 1029 mb
Low level cloud: 0%
Mid level cloud: 0%
High level cloud: 0%
Most Significant Cloud Type: high
0%
Expect 0.00 In of precipitation over the past 3 hours.
0.00 In
06:00

E
E

12 / 20 mph 44 / 38°F 79% 1030 mb
Low level cloud: 0%
Mid level cloud: 0%
High level cloud: 0%
Most Significant Cloud Type: high
0%
Expect 0.00 In of precipitation over the past 3 hours.
0.00 In
09:00

E
E

13 / 20 mph 46 / 40°F 78% 1030 mb
Low level cloud: 0%
Mid level cloud: 0%
High level cloud: 11%
Most Significant Cloud Type: high
10%
Expect 0.00 In of precipitation over the past 3 hours.
0.00 In
12:00

E
E

13 / 19 mph 49 / 44°F 64% 1030 mb
Low level cloud: 0%
Mid level cloud: 0%
High level cloud: 0%
Most Significant Cloud Type: high
0%
Expect 0.00 In of precipitation over the past 3 hours.
0.00 In
15:00

E
E

13 / 17 mph 50 / 46°F 66% 1030 mb
Low level cloud: 0%
Mid level cloud: 2%
High level cloud: 0%
Most Significant Cloud Type: medium
1%
Expect 0.00 In of precipitation over the past 3 hours.
0.00 In
18:00

E
E

14 / 16 mph 50 / 44°F 65% 1030 mb
Low level cloud: 0%
Mid level cloud: 5%
High level cloud: 0%
Most Significant Cloud Type: medium
5%
Expect 0.00 In of precipitation over the past 3 hours.
0.00 In
21:00

E
E

13 / 17 mph 47 / 42°F 69% 1030 mb
Low level cloud: 0%
Mid level cloud: 13%
High level cloud: 0%
Most Significant Cloud Type: medium
12%
Expect 0.00 In of precipitation over the past 3 hours.
0.00 In
Mon 19
Nov
00:00

ENE
ENE

13 / 24 mph 43 / 36°F 82% 1029 mb
Low level cloud: 0%
Mid level cloud: 5%
High level cloud: 2%
Most Significant Cloud Type: medium
5%
Expect 0.00 In of precipitation over the past 3 hours.
0.00 In
03:00

ENE
ENE

13 / 28 mph 41 / 33°F 87% 1028 mb
Low level cloud: 61%
Mid level cloud: 4%
High level cloud: 0%
Most Significant Cloud Type: low
62%
Expect 0.00 In of precipitation over the past 3 hours.
0.00 In
06:00

E
E

14 / 29 mph 40 / 32°F 82% 1027 mb
Low level cloud: 87%
Mid level cloud: 7%
High level cloud: 0%
Most Significant Cloud Type: low
89%
Expect 0.00 In of precipitation over the past 3 hours.
0.00 In
09:00

E
E

13 / 22 mph 43 / 35°F 73% 1028 mb
Low level cloud: 46%
Mid level cloud: 46%
High level cloud: 0%
Most Significant Cloud Type: low
62%
Expect 0.00 In of precipitation over the past 3 hours.
0.00 In
12:00

E
E

15 / 21 mph 45 / 39°F 70% 1027 mb
Low level cloud: 71%
Mid level cloud: 27%
High level cloud: 0%
Most Significant Cloud Type: low
80%
Expect 0.00 In of precipitation over the past 3 hours.
0.00 In
15:00

ENE
ENE

13 / 15 mph 47 / 41°F 68% 1026 mb
Low level cloud: 42%
Mid level cloud: 3%
High level cloud: 0%
Most Significant Cloud Type: low
43%
Expect 0.00 In of precipitation over the past 3 hours.
0.00 In
18:00

ENE
ENE

14 / 16 mph 45 / 39°F 70% 1025 mb
Low level cloud: 83%
Mid level cloud: 2%
High level cloud: 0%
Most Significant Cloud Type: low
83%
Expect 0.00 In of precipitation over the past 3 hours.
0.00 In
21:00

ENE
ENE

12 / 15 mph 43 / 37°F 72% 1025 mb
Low level cloud: 69%
Mid level cloud: 2%
High level cloud: 0%
Most Significant Cloud Type: low
69%
Expect 0.00 In of precipitation over the past 3 hours.
0.00 In
Tue 20
Nov
00:00

ENE
ENE

9 / 14 mph 41 / 35°F 75% 1024 mb
Low level cloud: 6%
Mid level cloud: 2%
High level cloud: 0%
Most Significant Cloud Type: low
6%
Expect 0.00 In of precipitation over the past 3 hours.
0.00 In
03:00

NE
NE

10 / 15 mph 39 / 33°F 79% 1023 mb
Low level cloud: 2%
Mid level cloud: 4%
High level cloud: 0%
Most Significant Cloud Type: medium
8%
Expect 0.00 In of precipitation over the past 3 hours.
0.00 In
06:00

NE
NE

10 / 15 mph 38 / 31°F 79% 1022 mb
Low level cloud: 1%
Mid level cloud: 8%
High level cloud: 0%
Most Significant Cloud Type: medium
10%
Expect 0.00 In of precipitation over the past 3 hours.
0.00 In
09:00

NE
NE

11 / 15 mph 40 / 33°F 75% 1021 mb
Low level cloud: 2%
Mid level cloud: 13%
High level cloud: 0%
Most Significant Cloud Type: medium
19%
Expect 0.00 In of precipitation over the past 3 hours.
0.00 In
12:00

NE
NE

14 / 20 mph 43 / 36°F 62% 1019 mb
Low level cloud: 21%
Mid level cloud: 21%
High level cloud: 0%
Most Significant Cloud Type: low
28%
Expect 0.00 In of precipitation over the past 3 hours.
0.00 In
15:00

NE
NE

13 / 15 mph 44 / 38°F 64% 1017 mb
Low level cloud: 8%
Mid level cloud: 25%
High level cloud: 0%
Most Significant Cloud Type: medium
48%
Expect 0.00 In of precipitation over the past 3 hours.
0.00 In
18:00

NE
NE

12 / 14 mph 43 / 37°F 74% 1018 mb
Low level cloud: 11%
Mid level cloud: 13%
High level cloud: 0%
Most Significant Cloud Type: low
15%
Expect 0.00 In of precipitation over the past 3 hours.
0.00 In
21:00

ENE
ENE

12 / 17 mph 41 / 35°F 77% 1018 mb
Low level cloud: 1%
Mid level cloud: 14%
High level cloud: 4%
Most Significant Cloud Type: medium
16%
Expect 0.00 In of precipitation over the past 3 hours.
0.00 In
Wed 21
Nov
00:00

NE
NE

10 / 14 mph 40 / 34°F 79% 1017 mb
Low level cloud: 1%
Mid level cloud: 16%
High level cloud: 13%
Most Significant Cloud Type: medium
19%
Expect 0.00 In of precipitation over the past 3 hours.
0.00 In
03:00

NNE
NNE

9 / 15 mph 39 / 32°F 83% 1016 mb
Low level cloud: 12%
Mid level cloud: 33%
High level cloud: 70%
Most Significant Cloud Type: low
31%
Expect 0.00 In of precipitation over the past 3 hours.
0.00 In
06:00

NNE
NNE

9 / 15 mph 38 / 31°F 84% 1015 mb
Low level cloud: 39%
Mid level cloud: 81%
High level cloud: 95%
Most Significant Cloud Type: low
79%
Expect 0.00 In of precipitation over the past 3 hours.
0.00 In
09:00

NNE
NNE

9 / 13 mph 40 / 34°F 83% 1015 mb
Low level cloud: 50%
Mid level cloud: 82%
High level cloud: 95%
Most Significant Cloud Type: low
90%
Expect 0.00 In of precipitation over the past 3 hours.
0.00 In
12:00

NE
NE

13 / 18 mph 43 / 37°F 70% 1014 mb
Low level cloud: 57%
Mid level cloud: 82%
High level cloud: 87%
Most Significant Cloud Type: low
96%
Expect 0.00 In of precipitation over the past 3 hours.
0.00 In
15:00

ENE
ENE

10 / 12 mph 45 / 40°F 72% 1013 mb
Low level cloud: 5%
Mid level cloud: 73%
High level cloud: 26%
Most Significant Cloud Type: medium
87%
Expect 0.00 In of precipitation over the past 3 hours.
0.00 In
18:00

ENE
ENE

8 / 9 mph 44 / 39°F 82% 1015 mb
Low level cloud: 9%
Mid level cloud: 27%
High level cloud: 33%
Most Significant Cloud Type: medium
53%
Expect 0.00 In of precipitation over the past 3 hours.
0.00 In
21:00

NE
NE

6 / 8 mph 41 / 37°F 87% 1016 mb
Low level cloud: 13%
Mid level cloud: 42%
High level cloud: 86%
Most Significant Cloud Type: medium
82%
Expect 0.00 In of precipitation over the past 3 hours.
0.00 In
DayLocal TimeDirSpeed/
Gust
Temp/
Feels Like
HumidityPressureCloud AmountPrecip AmountWeather
Thu 22
Nov
00:00

NNE
NNE

7 / 11 mph 40 / 36°F 87% 1018 mb
Low level cloud: 59%
Mid level cloud: 80%
High level cloud: 0%
Most Significant Cloud Type: low
86%
0.05 In
06:00

NNW
NNW

7 / 12 mph 43 / 38°F 87% 1024 mb
Low level cloud: 75%
Mid level cloud: 0%
High level cloud: 0%
Most Significant Cloud Type: low
75%
0.01 In
12:00

SW
SW

3 / 4 mph 42 / 40°F 71% 1014 mb
Low level cloud: 0%
Mid level cloud: 74%
High level cloud: 100%
Most Significant Cloud Type: medium
78%
0.00 In
18:00

NE
NE

8 / 9 mph 46 / 42°F 81% 1032 mb
Low level cloud: 27%
Mid level cloud: 0%
High level cloud: 0%
Most Significant Cloud Type: low
26%
0.00 In
Fri 23
Nov
00:00

NNE
NNE

5 / 8 mph 39 / 35°F 82% 1032 mb
Low level cloud: 30%
Mid level cloud: 31%
High level cloud: 2%
Most Significant Cloud Type: low
41%
0.00 In
06:00

N
N

11 / 24 mph 36 / 29°F 84% 1009 mb
Low level cloud: 73%
Mid level cloud: 49%
High level cloud: 0%
Most Significant Cloud Type: low
90%
0.00 In
12:00

NNW
NNW

7 / 8 mph 43 / 39°F 73% 1029 mb
Low level cloud: 33%
Mid level cloud: 8%
High level cloud: 4%
Most Significant Cloud Type: low
36%
0.00 In
18:00

NE
NE

11 / 13 mph 45 / 40°F 80% 1019 mb
Low level cloud: 14%
Mid level cloud: 14%
High level cloud: 0%
Most Significant Cloud Type: low
18%
0.00 In
Sat 24
Nov
00:00

NNW
NNW

7 / 11 mph 38 / 33°F 88% 1027 mb
Low level cloud: 51%
Mid level cloud: 0%
High level cloud: 0%
Most Significant Cloud Type: low
51%
0.00 In
06:00

NNE
NNE

6 / 7 mph 39 / 35°F 86% 1019 mb
Low level cloud: 1%
Mid level cloud: 0%
High level cloud: 1%
Most Significant Cloud Type: low
1%
0.00 In
12:00

NE
NE

12 / 15 mph 41 / 34°F 66% 1027 mb
Low level cloud: 62%
Mid level cloud: 45%
High level cloud: 0%
Most Significant Cloud Type: low
78%
0.01 In
18:00

NNW
NNW

3 / 3 mph 43 / 42°F 86% 1007 mb
Low level cloud: 9%
Mid level cloud: 61%
High level cloud: 0%
Most Significant Cloud Type: medium
85%
0.02 In
Sun 25
Nov
00:00

NNE
NNE

16 / 29 mph 35 / 25°F 76% 1031 mb
Low level cloud: 3%
Mid level cloud: 18%
High level cloud: 0%
Most Significant Cloud Type: medium
27%
0.01 In
06:00

NE
NE

8 / 12 mph 35 / 28°F 89% 1005 mb
Low level cloud: 32%
Mid level cloud: 86%
High level cloud: 32%
Most Significant Cloud Type: low
66%
0.07 In
12:00

NE
NE

14 / 21 mph 39 / 31°F 68% 1036 mb
Low level cloud: 5%
Mid level cloud: 21%
High level cloud: 11%
Most Significant Cloud Type: medium
36%
0.00 In
18:00

ENE
ENE

13 / 18 mph 37 / 29°F 83% 1011 mb
Low level cloud: 19%
Mid level cloud: 62%
High level cloud: 71%
Most Significant Cloud Type: medium
100%
0.02 In
Mon 26
Nov
00:00

W
W

5 / 7 mph 37 / 32°F 75% 1032 mb
Low level cloud: 62%
Mid level cloud: 61%
High level cloud: 0%
Most Significant Cloud Type: low
83%
0.01 In
06:00

NE
NE

13 / 26 mph 32 / 22°F 83% 1013 mb
Low level cloud: 22%
Mid level cloud: 83%
High level cloud: 88%
Most Significant Cloud Type: medium
100%
0.02 In
12:00

N
N

14 / 20 mph 38 / 30°F 81% 1029 mb
Low level cloud: 34%
Mid level cloud: 22%
High level cloud: 0%
Most Significant Cloud Type: low
41%
0.08 In
18:00

ENE
ENE

13 / 15 mph 36 / 27°F 77% 1017 mb
Low level cloud: 0%
Mid level cloud: 60%
High level cloud: 55%
Most Significant Cloud Type: medium
61%
0.00 In
Tue 27
Nov
00:00

NW
NW

8 / 14 mph 34 / 27°F 83% 1027 mb
Low level cloud: 0%
Mid level cloud: 52%
High level cloud: 60%
Most Significant Cloud Type: medium
53%
0.00 In
06:00

NE
NE

11 / 18 mph 31 / 22°F 82% 1019 mb
Low level cloud: 43%
Mid level cloud: 62%
High level cloud: 78%
Most Significant Cloud Type: low
74%
0.00 In
12:00

NNW
NNW

10 / 14 mph 42 / 36°F 83% 1016 mb
Low level cloud: 2%
Mid level cloud: 35%
High level cloud: 0%
Most Significant Cloud Type: medium
41%
0.12 In
18:00

NE
NE

10 / 12 mph 37 / 29°F 83% 1021 mb
Low level cloud: 25%
Mid level cloud: 45%
High level cloud: 68%
Most Significant Cloud Type: low
48%
0.03 In
Wed 28
Nov
00:00

NNW
NNW

11 / 19 mph 34 / 26°F 87% 1013 mb
Low level cloud: 27%
Mid level cloud: 32%
High level cloud: 0%
Most Significant Cloud Type: low
37%
0.00 In
06:00

NNE
NNE

11 / 20 mph 29 / 19°F 81% 1023 mb
Low level cloud: 6%
Mid level cloud: 27%
High level cloud: 2%
Most Significant Cloud Type: medium
44%
0.00 In
12:00

NNW
NNW

18 / 23 mph 37 / 27°F 75% 1017 mb
Low level cloud: 47%
Mid level cloud: 13%
High level cloud: 0%
Most Significant Cloud Type: low
51%
0.00 In
18:00

NNE
NNE

9 / 11 mph 34 / 27°F 83% 1021 mb
Low level cloud: 13%
Mid level cloud: 45%
High level cloud: 0%
Most Significant Cloud Type: medium
80%
0.00 In
Thu 29
Nov
00:00

NW
NW

10 / 13 mph 32 / 24°F 74% 1021 mb
Low level cloud: 0%
Mid level cloud: 15%
High level cloud: 2%
Most Significant Cloud Type: medium
14%
0.00 In
06:00

N
N

10 / 17 mph 28 / 19°F 86% 1018 mb
Low level cloud: 1%
Mid level cloud: 30%
High level cloud: 0%
Most Significant Cloud Type: medium
33%
0.00 In
12:00

W
W

14 / 19 mph 40 / 32°F 78% 1016 mb
Low level cloud: 66%
Mid level cloud: 58%
High level cloud: 66%
Most Significant Cloud Type: low
93%
0.01 In
18:00

NNW
NNW

6 / 7 mph 35 / 30°F 86% 1016 mb
Low level cloud: 0%
Mid level cloud: 44%
High level cloud: 77%
Most Significant Cloud Type: medium
46%
0.00 In
Fri 30
Nov
00:00

NNW
NNW

11 / 17 mph 32 / 23°F 79% 1014 mb
Low level cloud: 0%
Mid level cloud: 6%
High level cloud: 3%
Most Significant Cloud Type: medium
6%
0.05 In
06:00

WSW
WSW

7 / 15 mph 30 / 23°F 90% 1009 mb
Low level cloud: 20%
Mid level cloud: 28%
High level cloud: 57%
Most Significant Cloud Type: low
37%
0.00 In
12:00

NNW
NNW

14 / 18 mph 36 / 27°F 59% 1019 mb
Low level cloud: 0%
Mid level cloud: 0%
High level cloud: 0%
Most Significant Cloud Type: high
0%
0.00 In
18:00

NW
NW

7 / 9 mph 37 / 31°F 91% 1004 mb
Low level cloud: 1%
Mid level cloud: 60%
High level cloud: 0%
Most Significant Cloud Type: medium
63%
0.10 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