WEATHER FOR BUSINESS

We supply weather data to businesses

Free Weather Plugin

Add this forecast to your website



Local Weather

Tver' 14 Day Long Range Forecast

14 Day weather providing an extended long range forecast outlook for Tver'

Russia

Long range weather outlook for Tver' includes 14 day forecast summary:

Taking a look at Tver' over the coming two weeks and the average daytime maximum temperature will be around 24°C, with a high for the two weeks of 28°C expected on the afternoon of Tuesday 28th. The mean minimum temperature will be 11°C, dipping to its lowest on the morning of Friday 24th at 6°C. Expect the coming 14 days to have mixed weather with some days dry and some seeing a little rain. The indicators are that Tuesday 21st will have the most precipitation with an accumulation of around 3.0mm. On the whole winds are likely to be light.

DayLocal TimeDirSpeed/
Gust
Temp/
Feels Like
HumidityPressureCloud AmountPrecip AmountWeather
Sun 19
May
18:00

S
S

6 / 7 mph 72 / 69°F 48% 1017 mb
Low level cloud: 0%
Mid level cloud: 26%
High level cloud: 0%
Most Significant Cloud Type: medium
26%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
21:00

SSW
SSW

7 / 15 mph 57 / 55°F 77% 1017 mb
Low level cloud: 0%
Mid level cloud: 10%
High level cloud: 0%
Most Significant Cloud Type: medium
9%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
Mon 20
May
00:00

S
S

6 / 13 mph 52 / 49°F 91% 1017 mb
Low level cloud: 0%
Mid level cloud: 17%
High level cloud: 0%
Most Significant Cloud Type: medium
16%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
03:00

SSW
SSW

6 / 13 mph 50 / 47°F 94% 1017 mb
Low level cloud: 0%
Mid level cloud: 14%
High level cloud: 0%
Most Significant Cloud Type: medium
13%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
06:00

SSW
SSW

6 / 11 mph 53 / 50°F 83% 1017 mb
Low level cloud: 0%
Mid level cloud: 12%
High level cloud: 0%
Most Significant Cloud Type: medium
12%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
09:00

WSW
WSW

7 / 8 mph 67 / 65°F 58% 1017 mb
Low level cloud: 0%
Mid level cloud: 11%
High level cloud: 0%
Most Significant Cloud Type: medium
11%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
12:00

WSW
WSW

8 / 10 mph 74 / 76°F 43% 1016 mb
Low level cloud: 0%
Mid level cloud: 45%
High level cloud: 0%
Most Significant Cloud Type: medium
44%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
15:00

WSW
WSW

8 / 10 mph 74 / 75°F 42% 1016 mb
Low level cloud: 0%
Mid level cloud: 25%
High level cloud: 5%
Most Significant Cloud Type: medium
25%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
18:00

SW
SW

9 / 11 mph 73 / 76°F 51% 1016 mb
Low level cloud: 0%
Mid level cloud: 15%
High level cloud: 5%
Most Significant Cloud Type: medium
15%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
21:00

SW
SW

5 / 11 mph 62 / 62°F 65% 1017 mb
Low level cloud: 0%
Mid level cloud: 46%
High level cloud: 11%
Most Significant Cloud Type: medium
46%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
Tue 21
May
00:00

NW
NW

1 / 3 mph 57 / 57°F 79% 1018 mb
Low level cloud: 0%
Mid level cloud: 22%
High level cloud: 13%
Most Significant Cloud Type: medium
22%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
03:00

SW
SW

4 / 9 mph 52 / 51°F 88% 1018 mb
Low level cloud: 0%
Mid level cloud: 45%
High level cloud: 32%
Most Significant Cloud Type: medium
46%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
06:00

W
W

3 / 5 mph 57 / 55°F 86% 1019 mb
Low level cloud: 4%
Mid level cloud: 58%
High level cloud: 14%
Most Significant Cloud Type: medium
68%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
09:00

W
W

3 / 3 mph 65 / 63°F 74% 1019 mb
Low level cloud: 34%
Mid level cloud: 92%
High level cloud: 4%
Most Significant Cloud Type: low
66%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
12:00

NNW
NNW

3 / 4 mph 73 / 69°F 60% 1019 mb
Low level cloud: 33%
Mid level cloud: 20%
High level cloud: 0%
Most Significant Cloud Type: low
40%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
15:00

N
N

5 / 7 mph 73 / 76°F 59% 1019 mb
Low level cloud: 43%
Mid level cloud: 10%
High level cloud: 2%
Most Significant Cloud Type: low
46%
Expect 0.1 In of precipitation over the past 3 hours.
0.1 In
18:00

NNE
NNE

4 / 5 mph 73 / 76°F 59% 1019 mb
Low level cloud: 13%
Mid level cloud: 19%
High level cloud: 0%
Most Significant Cloud Type: low
19%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
21:00

NNE
NNE

4 / 9 mph 63 / 60°F 77% 1019 mb
Low level cloud: 0%
Mid level cloud: 16%
High level cloud: 3%
Most Significant Cloud Type: medium
16%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
Wed 22
May
00:00

NNE
NNE

3 / 6 mph 54 / 55°F 85% 1020 mb
Low level cloud: 0%
Mid level cloud: 46%
High level cloud: 0%
Most Significant Cloud Type: medium
47%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
03:00

N
N

4 / 8 mph 51 / 50°F 87% 1021 mb
Low level cloud: 0%
Mid level cloud: 37%
High level cloud: 0%
Most Significant Cloud Type: medium
37%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
06:00

NNE
NNE

4 / 8 mph 53 / 51°F 85% 1021 mb
Low level cloud: 1%
Mid level cloud: 11%
High level cloud: 2%
Most Significant Cloud Type: medium
13%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
09:00

ENE
ENE

7 / 8 mph 63 / 61°F 64% 1022 mb
Low level cloud: 9%
Mid level cloud: 5%
High level cloud: 1%
Most Significant Cloud Type: low
11%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
12:00

NE
NE

9 / 10 mph 68 / 66°F 44% 1023 mb
Low level cloud: 0%
Mid level cloud: 5%
High level cloud: 0%
Most Significant Cloud Type: medium
4%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
15:00

NE
NE

10 / 11 mph 69 / 67°F 37% 1022 mb
Low level cloud: 0%
Mid level cloud: 4%
High level cloud: 0%
Most Significant Cloud Type: medium
4%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
18:00

ENE
ENE

9 / 11 mph 67 / 65°F 46% 1023 mb
Low level cloud: 0%
Mid level cloud: 9%
High level cloud: 2%
Most Significant Cloud Type: medium
9%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
21:00

ENE
ENE

8 / 14 mph 56 / 53°F 63% 1025 mb
Low level cloud: 0%
Mid level cloud: 9%
High level cloud: 8%
Most Significant Cloud Type: medium
9%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
Thu 23
May
00:00

ENE
ENE

7 / 13 mph 50 / 47°F 72% 1027 mb
Low level cloud: 0%
Mid level cloud: 10%
High level cloud: 9%
Most Significant Cloud Type: medium
10%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
03:00

E
E

7 / 13 mph 46 / 42°F 77% 1028 mb
Low level cloud: 0%
Mid level cloud: 14%
High level cloud: 8%
Most Significant Cloud Type: medium
13%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
06:00

E
E

7 / 11 mph 47 / 43°F 73% 1030 mb
Low level cloud: 0%
Mid level cloud: 19%
High level cloud: 11%
Most Significant Cloud Type: medium
19%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
09:00

E
E

9 / 10 mph 57 / 54°F 48% 1030 mb
Low level cloud: 0%
Mid level cloud: 5%
High level cloud: 20%
Most Significant Cloud Type: medium
5%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
12:00

E
E

8 / 9 mph 63 / 61°F 35% 1030 mb
Low level cloud: 0%
Mid level cloud: 0%
High level cloud: 11%
Most Significant Cloud Type: high
11%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
15:00

E
E

6 / 6 mph 65 / 63°F 31% 1029 mb
Low level cloud: 0%
Mid level cloud: 1%
High level cloud: 5%
Most Significant Cloud Type: high
5%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
18:00

E
E

5 / 6 mph 66 / 63°F 36% 1029 mb
Low level cloud: 0%
Mid level cloud: 0%
High level cloud: 10%
Most Significant Cloud Type: high
9%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
21:00

ESE
ESE

5 / 9 mph 55 / 52°F 60% 1030 mb
Low level cloud: 0%
Mid level cloud: 1%
High level cloud: 4%
Most Significant Cloud Type: high
3%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
Fri 24
May
00:00

SSE
SSE

4 / 9 mph 47 / 46°F 62% 1031 mb
Low level cloud: 0%
Mid level cloud: 1%
High level cloud: 14%
Most Significant Cloud Type: high
13%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
03:00

SSW
SSW

4 / 7 mph 45 / 44°F 64% 1032 mb
Low level cloud: 0%
Mid level cloud: 4%
High level cloud: 5%
Most Significant Cloud Type: medium
4%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
06:00

SW
SW

3 / 5 mph 48 / 47°F 63% 1032 mb
Low level cloud: 0%
Mid level cloud: 2%
High level cloud: 4%
Most Significant Cloud Type: medium
2%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
09:00

WSW
WSW

4 / 4 mph 61 / 59°F 45% 1032 mb
Low level cloud: 0%
Mid level cloud: 0%
High level cloud: 3%
Most Significant Cloud Type: high
3%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
12:00

WNW
WNW

2 / 2 mph 71 / 68°F 36% 1031 mb
Low level cloud: 0%
Mid level cloud: 1%
High level cloud: 39%
Most Significant Cloud Type: high
38%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
15:00

W
W

2 / 2 mph 73 / 74°F 35% 1031 mb
Low level cloud: 0%
Mid level cloud: 3%
High level cloud: 11%
Most Significant Cloud Type: medium
3%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
18:00

WNW
WNW

1 / 1 mph 73 / 75°F 40% 1030 mb
Low level cloud: 0%
Mid level cloud: 3%
High level cloud: 9%
Most Significant Cloud Type: medium
3%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
21:00

SW
SW

6 / 11 mph 62 / 60°F 66% 1031 mb
Low level cloud: 0%
Mid level cloud: 3%
High level cloud: 7%
Most Significant Cloud Type: medium
2%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
Sat 25
May
00:00

WSW
WSW

5 / 11 mph 56 / 55°F 69% 1032 mb
Low level cloud: 0%
Mid level cloud: 2%
High level cloud: 8%
Most Significant Cloud Type: medium
2%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
03:00

W
W

5 / 11 mph 52 / 50°F 74% 1033 mb
Low level cloud: 0%
Mid level cloud: 3%
High level cloud: 8%
Most Significant Cloud Type: medium
2%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
06:00

W
W

4 / 9 mph 54 / 52°F 72% 1034 mb
Low level cloud: 0%
Mid level cloud: 3%
High level cloud: 1%
Most Significant Cloud Type: medium
3%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
09:00

W
W

4 / 4 mph 68 / 65°F 50% 1034 mb
Low level cloud: 0%
Mid level cloud: 3%
High level cloud: 1%
Most Significant Cloud Type: medium
3%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
12:00

SW
SW

5 / 6 mph 75 / 75°F 38% 1033 mb
Low level cloud: 0%
Mid level cloud: 2%
High level cloud: 4%
Most Significant Cloud Type: medium
2%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
15:00

SW
SW

7 / 8 mph 77 / 76°F 34% 1032 mb
Low level cloud: 0%
Mid level cloud: 3%
High level cloud: 0%
Most Significant Cloud Type: medium
2%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
18:00

SW
SW

7 / 8 mph 78 / 77°F 45% 1031 mb
Low level cloud: 0%
Mid level cloud: 2%
High level cloud: 0%
Most Significant Cloud Type: medium
2%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
21:00

WSW
WSW

6 / 10 mph 68 / 66°F 68% 1031 mb
Low level cloud: 0%
Mid level cloud: 0%
High level cloud: 1%
Most Significant Cloud Type: high
0%
Expect 0.0 In of precipitation over the past 3 hours.
0.0 In
DayLocal TimeDirSpeed/
Gust
Temp/
Feels Like
HumidityPressureCloud AmountPrecip AmountWeather
Sun 26
May
03:00

WSW
WSW

4 / 9 mph 60 / 60°F 87% 1023 mb
Low level cloud: 0%
Mid level cloud: 46%
High level cloud: 11%
Most Significant Cloud Type: medium
46%
0.0 In
09:00

W
W

5 / 11 mph 69 / 69°F 56% 1031 mb
Low level cloud: 0%
Mid level cloud: 17%
High level cloud: 2%
Most Significant Cloud Type: medium
17%
0.0 In
15:00

W
W

13 / 26 mph 74 / 76°F 39% 1015 mb
Low level cloud: 0%
Mid level cloud: 26%
High level cloud: 100%
Most Significant Cloud Type: medium
30%
0.0 In
21:00

E
E

5 / 10 mph 64 / 64°F 75% 1017 mb
Low level cloud: 0%
Mid level cloud: 16%
High level cloud: 18%
Most Significant Cloud Type: medium
16%
0.0 In
Mon 27
May
03:00

WSW
WSW

4 / 9 mph 57 / 57°F 94% 1021 mb
Low level cloud: 0%
Mid level cloud: 18%
High level cloud: 1%
Most Significant Cloud Type: medium
18%
0.0 In
09:00

E
E

8 / 15 mph 62 / 62°F 68% 1028 mb
Low level cloud: 0%
Mid level cloud: 22%
High level cloud: 0%
Most Significant Cloud Type: medium
21%
0.0 In
15:00

NNW
NNW

2 / 4 mph 82 / 81°F 35% 1026 mb
Low level cloud: 0%
Mid level cloud: 18%
High level cloud: 0%
Most Significant Cloud Type: medium
18%
0.0 In
21:00

W
W

4 / 8 mph 67 / 67°F 67% 1025 mb
Low level cloud: 0%
Mid level cloud: 32%
High level cloud: 8%
Most Significant Cloud Type: medium
31%
0.0 In
Tue 28
May
03:00

W
W

4 / 9 mph 63 / 63°F 77% 1026 mb
Low level cloud: 0%
Mid level cloud: 10%
High level cloud: 12%
Most Significant Cloud Type: medium
10%
0.0 In
09:00

NNW
NNW

2 / 3 mph 76 / 78°F 51% 1024 mb
Low level cloud: 0%
Mid level cloud: 11%
High level cloud: 19%
Most Significant Cloud Type: medium
11%
0.0 In
15:00

NNW
NNW

1 / 2 mph 81 / 80°F 34% 1023 mb
Low level cloud: 0%
Mid level cloud: 46%
High level cloud: 0%
Most Significant Cloud Type: medium
45%
0.0 In
21:00

WSW
WSW

1 / 1 mph 66 / 66°F 73% 1022 mb
Low level cloud: 0%
Mid level cloud: 44%
High level cloud: 2%
Most Significant Cloud Type: medium
43%
0.0 In
Wed 29
May
03:00

NW
NW

3 / 7 mph 63 / 64°F 65% 1023 mb
Low level cloud: 0%
Mid level cloud: 27%
High level cloud: 9%
Most Significant Cloud Type: medium
27%
0.0 In
09:00

E
E

4 / 7 mph 74 / 77°F 59% 1022 mb
Low level cloud: 0%
Mid level cloud: 15%
High level cloud: 0%
Most Significant Cloud Type: medium
14%
0.0 In
15:00

W
W

2 / 4 mph 81 / 80°F 37% 1021 mb
Low level cloud: 0%
Mid level cloud: 45%
High level cloud: 1%
Most Significant Cloud Type: medium
45%
0.0 In
21:00

WNW
WNW

2 / 4 mph 68 / 68°F 84% 1021 mb
Low level cloud: 0%
Mid level cloud: 15%
High level cloud: 0%
Most Significant Cloud Type: medium
14%
0.0 In
Thu 30
May
03:00

SW
SW

1 / 2 mph 65 / 65°F 74% 1021 mb
Low level cloud: 0%
Mid level cloud: 10%
High level cloud: 11%
Most Significant Cloud Type: medium
10%
0.0 In
09:00

SE
SE

5 / 9 mph 72 / 76°F 65% 1023 mb
Low level cloud: 0%
Mid level cloud: 11%
High level cloud: 4%
Most Significant Cloud Type: medium
11%
0.0 In
15:00

WSW
WSW

4 / 7 mph 79 / 80°F 48% 1019 mb
Low level cloud: 0%
Mid level cloud: 46%
High level cloud: 2%
Most Significant Cloud Type: medium
46%
0.0 In
21:00

SSW
SSW

2 / 4 mph 69 / 69°F 84% 1023 mb
Low level cloud: 0%
Mid level cloud: 13%
High level cloud: 88%
Most Significant Cloud Type: medium
16%
0.1 In
Fri 31
May
03:00

WNW
WNW

1 / 2 mph 65 / 65°F 80% 1020 mb
Low level cloud: 0%
Mid level cloud: 47%
High level cloud: 34%
Most Significant Cloud Type: medium
48%
0.0 In
09:00

S
S

4 / 8 mph 74 / 77°F 65% 1024 mb
Low level cloud: 0%
Mid level cloud: 19%
High level cloud: 33%
Most Significant Cloud Type: medium
20%
0.0 In
15:00

NE
NE

11 / 24 mph 72 / 76°F 54% 1021 mb
Low level cloud: 1%
Mid level cloud: 43%
High level cloud: 17%
Most Significant Cloud Type: medium
47%
0.0 In
21:00

SE
SE

5 / 11 mph 71 / 71°F 69% 1022 mb
Low level cloud: 0%
Mid level cloud: 23%
High level cloud: 15%
Most Significant Cloud Type: medium
23%
0.0 In
Sat 01
Jun
03:00

ENE
ENE

6 / 13 mph 53 / 51°F 76% 1028 mb
Low level cloud: 0%
Mid level cloud: 0%
High level cloud: 0%
Most Significant Cloud Type: high
0%
0.0 In
09:00

S
S

7 / 14 mph 72 / 72°F 60% 1022 mb
Low level cloud: 0%
Mid level cloud: 0%
High level cloud: 4%
Most Significant Cloud Type: high
3%
0.0 In
15:00

E
E

7 / 15 mph 72 / 74°F 32% 1028 mb
Low level cloud: 0%
Mid level cloud: 0%
High level cloud: 5%
Most Significant Cloud Type: high
5%
0.0 In
21:00

SW
SW

6 / 12 mph 71 / 71°F 69% 1019 mb
Low level cloud: 0%
Mid level cloud: 21%
High level cloud: 58%
Most Significant Cloud Type: medium
23%
0.0 In
Sun 02
Jun
03:00

SSE
SSE

3 / 6 mph 55 / 56°F 73% 1029 mb
Low level cloud: 0%
Mid level cloud: 0%
High level cloud: 2%
Most Significant Cloud Type: high
2%
0.0 In
09:00

SSW
SSW

9 / 19 mph 70 / 70°F 64% 1018 mb
Low level cloud: 2%
Mid level cloud: 44%
High level cloud: 13%
Most Significant Cloud Type: medium
50%
0.0 In
15:00

S
S

4 / 9 mph 79 / 78°F 32% 1026 mb
Low level cloud: 0%
Mid level cloud: 0%
High level cloud: 0%
Most Significant Cloud Type: high
0%
0.0 In
21:00

SSW
SSW

6 / 13 mph 66 / 65°F 87% 1014 mb
Low level cloud: 0%
Mid level cloud: 43%
High level cloud: 79%
Most Significant Cloud Type: medium
46%
0.2 In
Mon 03
Jun
03:00

WSW
WSW

5 / 11 mph 57 / 56°F 82% 1024 mb
Low level cloud: 0%
Mid level cloud: 0%
High level cloud: 1%
Most Significant Cloud Type: high
0%
0.0 In
09:00

WNW
WNW

4 / 9 mph 62 / 62°F 97% 1012 mb
Low level cloud: 92%
Mid level cloud: 67%
High level cloud: 100%
Most Significant Cloud Type: low
100%
0.2 In
15:00

WSW
WSW

4 / 8 mph 83 / 82°F 32% 1018 mb
Low level cloud: 0%
Mid level cloud: 11%
High level cloud: 0%
Most Significant Cloud Type: medium
10%
0.0 In
21:00

NE
NE

7 / 15 mph 54 / 52°F 76% 1018 mb
Low level cloud: 0%
Mid level cloud: 15%
High level cloud: 0%
Most Significant Cloud Type: medium
15%
0.1 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