WEATHER FOR BUSINESS

We supply weather data to businesses

Free Weather Plugin

Add this forecast to your website



Local Weather

Castelnau-de-Montmiral 14 Day Long Range Forecast

14 Day weather providing an extended long range forecast outlook for Castelnau-de-Montmiral

France

Long range weather outlook for Castelnau-de-Montmiral includes 14 day forecast summary:

Over the next 14 days the Castelnau-de-Montmiral forecast suggests the average daytime maximum temperature will be around 9°C, with a high for the two weeks of 13°C expected on the evening of Friday 30th. The mean minimum temperature will be 5°C, dipping to its lowest on the morning of Saturday 24th at 3°C. The next 14 days will have some days seeing a little precipitation and some days with rain. The current forecast indicates Sunday 1st 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
Thu 22
Jan
19:30

W
W

9 / 15 mph 48 / 44°F 78% 1000 mb
Low level cloud: 63%
Mid level cloud: 45%
High level cloud: 0%
Most Significant Cloud Type: low
78%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
22:30

WSW
WSW

5 / 7 mph 47 / 45°F 92% 1001 mb
Low level cloud: 21%
Mid level cloud: 36%
High level cloud: 0%
Most Significant Cloud Type: low
33%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
Fri 23
Jan
01:30

SE
SE

4 / 7 mph 42 / 40°F 95% 999 mb
Low level cloud: 33%
Mid level cloud: 9%
High level cloud: 2%
Most Significant Cloud Type: low
36%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
04:30

ESE
ESE

5 / 11 mph 41 / 37°F 96% 997 mb
Low level cloud: 10%
Mid level cloud: 4%
High level cloud: 78%
Most Significant Cloud Type: low
20%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
07:30

ESE
ESE

8 / 15 mph 42 / 37°F 86% 994 mb
Low level cloud: 0%
Mid level cloud: 69%
High level cloud: 25%
Most Significant Cloud Type: medium
70%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
10:30

S
S

2 / 4 mph 43 / 43°F 91% 996 mb
Low level cloud: 14%
Mid level cloud: 71%
High level cloud: 10%
Most Significant Cloud Type: medium
100%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
13:30

S
S

3 / 5 mph 44 / 42°F 95% 998 mb
Low level cloud: 11%
Mid level cloud: 44%
High level cloud: 0%
Most Significant Cloud Type: medium
75%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
16:30

SW
SW

6 / 7 mph 48 / 45°F 70% 997 mb
Low level cloud: 2%
Mid level cloud: 54%
High level cloud: 0%
Most Significant Cloud Type: medium
58%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
19:30

WSW
WSW

4 / 5 mph 49 / 48°F 63% 996 mb
Low level cloud: 0%
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
22:30

E
E

5 / 9 mph 42 / 40°F 83% 997 mb
Low level cloud: 0%
Mid level cloud: 7%
High level cloud: 0%
Most Significant Cloud Type: medium
7%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
Sat 24
Jan
01:30

E
E

6 / 13 mph 39 / 35°F 89% 998 mb
Low level cloud: 0%
Mid level cloud: 5%
High level cloud: 60%
Most Significant Cloud Type: medium
6%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
04:30

E
E

8 / 17 mph 39 / 33°F 83% 996 mb
Low level cloud: 0%
Mid level cloud: 45%
High level cloud: 88%
Most Significant Cloud Type: medium
48%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
07:30

ENE
ENE

7 / 13 mph 39 / 35°F 79% 994 mb
Low level cloud: 84%
Mid level cloud: 29%
High level cloud: 34%
Most Significant Cloud Type: low
98%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
10:30

S
S

4 / 7 mph 41 / 38°F 85% 994 mb
Low level cloud: 97%
Mid level cloud: 84%
High level cloud: 100%
Most Significant Cloud Type: low
100%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
13:30

WNW
WNW

9 / 13 mph 39 / 33°F 94% 996 mb
Low level cloud: 97%
Mid level cloud: 34%
High level cloud: 33%
Most Significant Cloud Type: low
100%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
16:30

WNW
WNW

9 / 11 mph 42 / 36°F 83% 997 mb
Low level cloud: 91%
Mid level cloud: 25%
High level cloud: 32%
Most Significant Cloud Type: low
100%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
19:30

WNW
WNW

12 / 16 mph 42 / 36°F 78% 997 mb
Low level cloud: 33%
Mid level cloud: 10%
High level cloud: 100%
Most Significant Cloud Type: low
47%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
22:30

WNW
WNW

7 / 10 mph 42 / 37°F 86% 1000 mb
Low level cloud: 97%
Mid level cloud: 99%
High level cloud: 100%
Most Significant Cloud Type: low
100%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
Sun 25
Jan
01:30

WNW
WNW

9 / 12 mph 40 / 34°F 90% 1003 mb
Low level cloud: 90%
Mid level cloud: 80%
High level cloud: 30%
Most Significant Cloud Type: low
100%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
04:30

W
W

8 / 11 mph 40 / 34°F 93% 1004 mb
Low level cloud: 97%
Mid level cloud: 99%
High level cloud: 9%
Most Significant Cloud Type: low
100%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
07:30

WNW
WNW

13 / 19 mph 41 / 34°F 94% 1004 mb
Low level cloud: 100%
Mid level cloud: 51%
High level cloud: 0%
Most Significant Cloud Type: low
100%
Expect 0.1 In of precipitation over the past 3 hours.
0.1 In
10:30

W
W

11 / 16 mph 40 / 33°F 93% 1006 mb
Low level cloud: 83%
Mid level cloud: 44%
High level cloud: 6%
Most Significant Cloud Type: low
99%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
13:30

W
W

9 / 13 mph 41 / 35°F 92% 1007 mb
Low level cloud: 91%
Mid level cloud: 45%
High level cloud: 4%
Most Significant Cloud Type: low
100%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
16:30

WSW
WSW

10 / 16 mph 44 / 38°F 80% 1005 mb
Low level cloud: 96%
Mid level cloud: 79%
High level cloud: 32%
Most Significant Cloud Type: low
100%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
19:30

W
W

17 / 24 mph 47 / 41°F 79% 1004 mb
Low level cloud: 84%
Mid level cloud: 58%
High level cloud: 7%
Most Significant Cloud Type: low
100%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
22:30

W
W

13 / 21 mph 45 / 39°F 81% 1005 mb
Low level cloud: 35%
Mid level cloud: 24%
High level cloud: 100%
Most Significant Cloud Type: low
55%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
Mon 26
Jan
01:30

W
W

16 / 26 mph 46 / 39°F 79% 1004 mb
Low level cloud: 39%
Mid level cloud: 100%
High level cloud: 100%
Most Significant Cloud Type: low
86%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
04:30

W
W

19 / 28 mph 45 / 37°F 86% 1004 mb
Low level cloud: 71%
Mid level cloud: 50%
High level cloud: 10%
Most Significant Cloud Type: low
89%
Expect 0.1 In of precipitation over the past 3 hours.
0.1 In
07:30

WNW
WNW

14 / 21 mph 43 / 36°F 90% 1005 mb
Low level cloud: 33%
Mid level cloud: 78%
High level cloud: 32%
Most Significant Cloud Type: low
64%
Expect 0.1 In of precipitation over the past 3 hours.
0.1 In
10:30

W
W

10 / 15 mph 42 / 36°F 94% 1006 mb
Low level cloud: 67%
Mid level cloud: 16%
High level cloud: 62%
Most Significant Cloud Type: low
80%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
13:30

W
W

6 / 8 mph 44 / 41°F 95% 1007 mb
Low level cloud: 82%
Mid level cloud: 45%
High level cloud: 96%
Most Significant Cloud Type: low
100%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
16:30

WNW
WNW

6 / 8 mph 45 / 42°F 88% 1007 mb
Low level cloud: 87%
Mid level cloud: 99%
High level cloud: 58%
Most Significant Cloud Type: low
100%
Expect 0.1 In of precipitation over the past 3 hours.
0.1 In
19:30

ENE
ENE

1 / 2 mph 44 / 44°F 92% 1007 mb
Low level cloud: 94%
Mid level cloud: 69%
High level cloud: 100%
Most Significant Cloud Type: low
100%
Expect 0.1 In of precipitation over the past 3 hours.
0.1 In
22:30

ESE
ESE

5 / 8 mph 43 / 40°F 93% 1007 mb
Low level cloud: 87%
Mid level cloud: 53%
High level cloud: 99%
Most Significant Cloud Type: low
100%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
Tue 27
Jan
01:30

ESE
ESE

4 / 6 mph 45 / 43°F 92% 1007 mb
Low level cloud: 96%
Mid level cloud: 100%
High level cloud: 99%
Most Significant Cloud Type: low
100%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
04:30

E
E

4 / 7 mph 44 / 42°F 92% 1005 mb
Low level cloud: 86%
Mid level cloud: 44%
High level cloud: 100%
Most Significant Cloud Type: low
100%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
07:30

ESE
ESE

5 / 10 mph 43 / 41°F 92% 1003 mb
Low level cloud: 23%
Mid level cloud: 95%
High level cloud: 88%
Most Significant Cloud Type: medium
100%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
10:30

ESE
ESE

5 / 10 mph 47 / 44°F 93% 1001 mb
Low level cloud: 4%
Mid level cloud: 46%
High level cloud: 90%
Most Significant Cloud Type: medium
59%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
13:30

ESE
ESE

6 / 8 mph 49 / 47°F 90% 1000 mb
Low level cloud: 1%
Mid level cloud: 83%
High level cloud: 100%
Most Significant Cloud Type: medium
90%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
16:30

SE
SE

5 / 7 mph 50 / 48°F 87% 999 mb
Low level cloud: 11%
Mid level cloud: 64%
High level cloud: 100%
Most Significant Cloud Type: medium
100%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
19:30

SE
SE

11 / 18 mph 48 / 43°F 89% 996 mb
Low level cloud: 21%
Mid level cloud: 100%
High level cloud: 96%
Most Significant Cloud Type: medium
100%
Expect 0.1 In of precipitation over the past 3 hours.
0.1 In
22:30

SE
SE

2 / 4 mph 46 / 47°F 97% 995 mb
Low level cloud: 53%
Mid level cloud: 56%
High level cloud: 100%
Most Significant Cloud Type: low
84%
Expect 0.2 In of precipitation over the past 3 hours.
0.2 In
Wed 28
Jan
01:30

NNW
NNW

6 / 9 mph 42 / 38°F 93% 1000 mb
Low level cloud: 96%
Mid level cloud: 21%
High level cloud: 18%
Most Significant Cloud Type: low
100%
Expect 0.1 In of precipitation over the past 3 hours.
0.1 In
04:30

W
W

4 / 5 mph 43 / 41°F 94% 1001 mb
Low level cloud: 65%
Mid level cloud: 46%
High level cloud: 77%
Most Significant Cloud Type: low
90%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
07:30

W
W

3 / 4 mph 42 / 41°F 94% 1001 mb
Low level cloud: 35%
Mid level cloud: 27%
High level cloud: 0%
Most Significant Cloud Type: low
44%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
10:30

SW
SW

2 / 4 mph 39 / 38°F 97% 1001 mb
Low level cloud: 53%
Mid level cloud: 43%
High level cloud: 0%
Most Significant Cloud Type: low
67%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
13:30

W
W

7 / 9 mph 41 / 37°F 92% 1002 mb
Low level cloud: 88%
Mid level cloud: 42%
High level cloud: 0%
Most Significant Cloud Type: low
100%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
16:30

WNW
WNW

12 / 15 mph 48 / 42°F 73% 1001 mb
Low level cloud: 24%
Mid level cloud: 37%
High level cloud: 0%
Most Significant Cloud Type: low
37%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
19:30

WNW
WNW

6 / 9 mph 49 / 46°F 67% 1000 mb
Low level cloud: 0%
Mid level cloud: 19%
High level cloud: 31%
Most Significant Cloud Type: medium
20%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
22:30

N
N

3 / 6 mph 43 / 42°F 86% 1001 mb
Low level cloud: 0%
Mid level cloud: 5%
High level cloud: 33%
Most Significant Cloud Type: medium
6%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
DayLocal TimeDirSpeed/
Gust
Temp/
Feels Like
HumidityPressureCloud AmountPrecip AmountWeather
Thu 29
Jan
04:30

E
E

6 / 11 mph 39 / 35°F 89% 1013 mb
Low level cloud: 0%
Mid level cloud: 15%
High level cloud: 100%
Most Significant Cloud Type: medium
19%
0.0 In
10:30

SSW
SSW

4 / 8 mph 49 / 47°F 95% 996 mb
Low level cloud: 93%
Mid level cloud: 87%
High level cloud: 54%
Most Significant Cloud Type: low
100%
0.0 In
16:30

SE
SE

7 / 14 mph 43 / 38°F 96% 999 mb
Low level cloud: 87%
Mid level cloud: 71%
High level cloud: 84%
Most Significant Cloud Type: low
100%
0.0 In
22:30

SE
SE

3 / 6 mph 51 / 51°F 90% 1006 mb
Low level cloud: 28%
Mid level cloud: 93%
High level cloud: 44%
Most Significant Cloud Type: medium
100%
0.0 In
Fri 30
Jan
04:30

WNW
WNW

6 / 11 mph 48 / 45°F 95% 1022 mb
Low level cloud: 56%
Mid level cloud: 80%
High level cloud: 0%
Most Significant Cloud Type: low
83%
0.0 In
10:30

W
W

10 / 20 mph 49 / 45°F 94% 1025 mb
Low level cloud: 62%
Mid level cloud: 17%
High level cloud: 42%
Most Significant Cloud Type: low
72%
0.0 In
16:30

SSE
SSE

4 / 9 mph 55 / 55°F 74% 1016 mb
Low level cloud: 11%
Mid level cloud: 4%
High level cloud: 40%
Most Significant Cloud Type: low
17%
0.0 In
22:30

SSE
SSE

3 / 6 mph 55 / 55°F 79% 1013 mb
Low level cloud: 0%
Mid level cloud: 13%
High level cloud: 99%
Most Significant Cloud Type: medium
16%
0.0 In
Sat 31
Jan
04:30

ESE
ESE

4 / 9 mph 43 / 41°F 89% 1013 mb
Low level cloud: 0%
Mid level cloud: 53%
High level cloud: 5%
Most Significant Cloud Type: medium
53%
0.0 In
10:30

SSE
SSE

3 / 6 mph 46 / 46°F 90% 1013 mb
Low level cloud: 84%
Mid level cloud: 71%
High level cloud: 32%
Most Significant Cloud Type: low
100%
0.0 In
16:30

W
W

11 / 22 mph 45 / 39°F 94% 1008 mb
Low level cloud: 95%
Mid level cloud: 99%
High level cloud: 89%
Most Significant Cloud Type: low
100%
0.2 In
22:30

WSW
WSW

5 / 10 mph 50 / 49°F 81% 1007 mb
Low level cloud: 80%
Mid level cloud: 83%
High level cloud: 99%
Most Significant Cloud Type: low
100%
0.0 In
Sun 01
Feb
04:30

WSW
WSW

14 / 30 mph 41 / 33°F 90% 1006 mb
Low level cloud: 100%
Mid level cloud: 57%
High level cloud: 99%
Most Significant Cloud Type: low
100%
0.1 In
10:30

W
W

7 / 16 mph 48 / 45°F 92% 1013 mb
Low level cloud: 94%
Mid level cloud: 20%
High level cloud: 0%
Most Significant Cloud Type: low
100%
0.5 In
16:30

W
W

20 / 42 mph 46 / 38°F 81% 1007 mb
Low level cloud: 70%
Mid level cloud: 15%
High level cloud: 0%
Most Significant Cloud Type: low
74%
0.2 In
22:30

WSW
WSW

9 / 19 mph 47 / 43°F 90% 1008 mb
Low level cloud: 74%
Mid level cloud: 100%
High level cloud: 98%
Most Significant Cloud Type: low
100%
0.3 In
Mon 02
Feb
04:30

SSE
SSE

2 / 5 mph 40 / 39°F 97% 1007 mb
Low level cloud: 58%
Mid level cloud: 17%
High level cloud: 33%
Most Significant Cloud Type: low
67%
0.1 In
10:30

W
W

11 / 23 mph 48 / 43°F 88% 1010 mb
Low level cloud: 16%
Mid level cloud: 15%
High level cloud: 0%
Most Significant Cloud Type: low
21%
0.1 In
16:30

ESE
ESE

16 / 34 mph 48 / 42°F 80% 991 mb
Low level cloud: 13%
Mid level cloud: 47%
High level cloud: 100%
Most Significant Cloud Type: medium
88%
0.0 In
22:30

W
W

17 / 35 mph 47 / 40°F 87% 1010 mb
Low level cloud: 93%
Mid level cloud: 90%
High level cloud: 18%
Most Significant Cloud Type: low
100%
0.1 In
Tue 03
Feb
04:30

SSE
SSE

3 / 7 mph 37 / 35°F 97% 986 mb
Low level cloud: 79%
Mid level cloud: 100%
High level cloud: 98%
Most Significant Cloud Type: low
100%
0.1 In
10:30

SSE
SSE

5 / 11 mph 47 / 45°F 92% 1006 mb
Low level cloud: 0%
Mid level cloud: 59%
High level cloud: 32%
Most Significant Cloud Type: medium
60%
0.6 In
16:30

SSE
SSE

9 / 18 mph 44 / 39°F 93% 989 mb
Low level cloud: 96%
Mid level cloud: 57%
High level cloud: 5%
Most Significant Cloud Type: low
100%
0.2 In
22:30

ESE
ESE

4 / 8 mph 47 / 46°F 98% 998 mb
Low level cloud: 28%
Mid level cloud: 77%
High level cloud: 99%
Most Significant Cloud Type: low
67%
0.6 In
Wed 04
Feb
04:30

W
W

10 / 21 mph 37 / 30°F 96% 1000 mb
Low level cloud: 99%
Mid level cloud: 49%
High level cloud: 13%
Most Significant Cloud Type: low
100%
0.5 In
10:30

W
W

16 / 33 mph 48 / 42°F 86% 1001 mb
Low level cloud: 87%
Mid level cloud: 45%
High level cloud: 20%
Most Significant Cloud Type: low
100%
0.7 In
16:30

W
W

8 / 17 mph 44 / 39°F 88% 1005 mb
Low level cloud: 91%
Mid level cloud: 50%
High level cloud: 0%
Most Significant Cloud Type: low
100%
0.1 In
22:30

WSW
WSW

11 / 22 mph 48 / 43°F 93% 1003 mb
Low level cloud: 91%
Mid level cloud: 98%
High level cloud: 79%
Most Significant Cloud Type: low
100%
0.1 In
Thu 05
Feb
04:30

WSW
WSW

4 / 7 mph 42 / 40°F 96% 1005 mb
Low level cloud: 95%
Mid level cloud: 88%
High level cloud: 0%
Most Significant Cloud Type: low
100%
0.0 In
10:30

W
W

16 / 33 mph 46 / 39°F 86% 1001 mb
Low level cloud: 75%
Mid level cloud: 100%
High level cloud: 0%
Most Significant Cloud Type: low
100%
0.3 In
16:30

W
W

7 / 15 mph 43 / 38°F 92% 1003 mb
Low level cloud: 95%
Mid level cloud: 52%
High level cloud: 0%
Most Significant Cloud Type: low
100%
0.0 In
22:30

NW
NW

22 / 46 mph 46 / 37°F 91% 997 mb
Low level cloud: 98%
Mid level cloud: 96%
High level cloud: 100%
Most Significant Cloud Type: low
100%
0.2 In
Fri 06
Feb
04:30

WNW
WNW

13 / 28 mph 38 / 30°F 94% 1004 mb
Low level cloud: 98%
Mid level cloud: 67%
High level cloud: 0%
Most Significant Cloud Type: low
100%
0.0 In
10:30

NW
NW

12 / 25 mph 42 / 35°F 93% 1010 mb
Low level cloud: 95%
Mid level cloud: 52%
High level cloud: 33%
Most Significant Cloud Type: low
100%
0.1 In
16:30

WNW
WNW

15 / 31 mph 43 / 36°F 74% 1013 mb
Low level cloud: 76%
Mid level cloud: 45%
High level cloud: 21%
Most Significant Cloud Type: low
94%
0.0 In
22:30

WNW
WNW

6 / 12 mph 42 / 38°F 92% 1016 mb
Low level cloud: 37%
Mid level cloud: 24%
High level cloud: 0%
Most Significant Cloud Type: low
45%
0.1 In

Other Locations Near to Castelnau-de-Montmiral

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