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Rule Fog Hunter

Phong Nha - Fog Hunter - Vietnam

Dong Hoi, Quảng Bình Province, Vietnam

Thick, moody fog for atmospheric forest and landscape shots

No opportunities right now
Here’s what usually blocks matches

No Fog Hunter opportunities in the next 14 days

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Rule requirements (key thresholds)
Fog Probability · ≥ 75.0%

Tip: Scroll down to the 72-hour table to see exactly which condition fails hour by hour.

Most common blockers (next 72 hours)
Fog Probability 100% failing

Currently

Real-time conditions
Dewpoint Spread8.0°C
Visibility24135 (Clear)
Relative Humidity62%
Wind Speed3.1m/s (calm conditions)

Upcoming Opportunities

When all conditions match, PhotoWeather marks an opportunity window.

Times shown in Asia/Bangkok

No opportunities in the next 10 days

See the blocker timeline below to understand which conditions are preventing matches.

What this forecast looks for

Plain-language explanation from the rule

This forecast predicts when temperature inversions and morning mist create atmospheric conditions across Vietnam's mountain valleys, rice terraces, and karst landscapes. We track overnight cooling, humidity, topography, and seasonal patterns to identify when fog transforms Vietnam's highland regions into ethereal scenes.

Vietnam's dramatic elevation changes—from sea level to 10,000-foot peaks—create ideal conditions for fog formation in mountain valleys. Northern highlands around Sapa and Mu Cang Chai experience frequent morning fog, particularly during the transition between dry and wet seasons. Hill stations like Da Lat maintain cooler temperatures that promote mist formation even in tropical latitudes. The limestone karsts of Ha Long Bay and Ninh Binh develop ethereal fog conditions during cooler months.

What makes Vietnam fog photography special:

  • Terraced valleys - Sapa and Mu Cang Chai rice terraces emerge layer by layer as fog burns off, creating depth and mystery
  • Karst landscapes - Ha Long Bay limestone islands pierce through low-lying fog like ancient towers floating on clouds
  • Mountain village life - Traditional H'mong and Dao villages in Sapa appear and disappear through drifting mist during morning hours
  • Highland agriculture - Da Lat's flower farms and strawberry fields gain dreamlike quality under morning fog blankets

Sapa experiences its most reliable fog from September through November and March through May—transition seasons when temperature differentials are greatest. Early morning (5-8 AM) provides peak conditions as fog fills valleys while higher villages remain clear. Mu Cang Chai's deep valleys create spectacular inversions, especially during harvest season (late September) when golden rice terraces emerge through fog layers. Da Lat's elevation (1,500 meters) generates morning mist year-round, peaking December through March. Ninh Binh's karsts become most atmospheric during cooler months (November-February) when mist drifts through limestone formations. Arrive at viewpoints well before dawn—fog often dissipates quickly after sunrise.

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72-hour requirements breakdown

What passed or failed, hour by hour
0matching hours in the next 95 hours
AND logic: all conditions required
Meets requirement
Misses requirement
Time
Asia/Bangkok
Fog Probability
≥ 75.0%
Sat, May 23
20:000%
21:000%
22:000%
23:000%
Sun, May 24
24:000%
01:000%
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Mon, May 25
24:000%
01:000%
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Tue, May 26
24:000%
01:000%
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Wed, May 27
24:000%
01:000%
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How to read: colored cells show whether each predicate requirement is met; highlighted rows mean the full rule matched (an opportunity).

What does Fog Probability mean?

Inputs that drive the score

This derived score summarizes multiple raw weather signals. The table below shows the supporting inputs hour by hour, so you can see what's pushing the score up or down.

Time
Asia/Bangkok
Clear Sky Probability (Ensemble)
%
Dew Point
°C
Rainfall
mm
Relative Humidity
%
Snowfall
cm
Solar Elevation
°
Temperature
°C
Total Precipitation
mm
Vapor Pressure Deficit
kPa
Visibility
m
Wind Gusts
m/s
Wind Speed
m/s
Sun, May 24 Sunrise 05:19 Sunset 18:21
20:00
18% 22°C 0mm 62% 0cm -22° 30°C 0mm 1.6kPa 24135m 5.4m/s 3.1m/s
21:00
27% 22°C 0mm 65% 0cm -33° 29°C 0mm 1.4kPa 24135m 3.3m/s 2.5m/s
22:00
37% 22°C 0mm 65% 0cm -43° 29°C 0mm 1.4kPa 24134m 2m/s 2m/s
23:00
36% 22°C 0mm 67% 0cm -50° 28°C 0mm 1.3kPa 24134m 1.9m/s 1.8m/s
Mon, May 25 Sunrise 05:19 Sunset 18:21
24:00
34% 22°C 0mm 68% 0cm -52° 28°C 0mm 1.2kPa 24134m 2.2m/s 2m/s
01:00
33% 22°C 0mm 64% 0cm -48° 29°C 0mm 1.4kPa 24134m 7.8m/s 2.9m/s
02:00
31% 21°C 0mm 57% 0cm -40° 31°C 0mm 1.9kPa 24135m 11m/s 4.4m/s
03:00
30% 21°C 0mm 59% 0cm -30° 30°C 0mm 1.8kPa 24134m 9.7m/s 4.3m/s
04:00
28% 22°C 0mm 61% 0cm -18° 30°C 0mm 1.6kPa 24135m 9.3m/s 3.8m/s
05:00
27% 22°C 0mm 64% 0cm -4.9° 29°C 0mm 1.4kPa 24134m 6m/s 2.7m/s
06:00
26% 22°C 0mm 69% 0cm 8.4° 29°C 0mm 1.2kPa 24135m 4.3m/s 2.3m/s
07:00
25% 23°C 0mm 64% 0cm 22° 30°C 0mm 1.5kPa 24135m 5.5m/s 2.3m/s
08:00
35% 23°C 0mm 56% 0cm 36° 32°C 0mm 2.1kPa 24135m 7.4m/s 3.1m/s
09:00
46% 22°C 0mm 50% 0cm 50° 34°C 0mm 2.7kPa 24135m 8.1m/s 4.3m/s
10:00
56% 22°C 0mm 43% 0cm 64° 36°C 0mm 3.4kPa 24135m 7.4m/s 4.3m/s
11:00
59% 21°C 0mm 39% 0cm 78° 37°C 0mm 3.9kPa 24134m 8m/s 5.3m/s
12:00
62% 21°C 0mm 37% 0cm 86° 38°C 0mm 4.2kPa 24134m 7.9m/s 5.8m/s
13:00
65% 21°C 0mm 35% 0cm 73° 39°C 0mm 4.5kPa 24134m 7.9m/s 6.5m/s
14:00
72% 20°C 0mm 35% 0cm 59° 39°C 0mm 4.4kPa 24135m 8.2m/s 7.1m/s
15:00
79% 22°C 0mm 41% 0cm 45° 37°C 0mm 3.7kPa 24134m 9.1m/s 8m/s
16:00
86% 21°C 0mm 42% 0cm 31° 36°C 0mm 3.5kPa 24135m 9.9m/s 6.1m/s
17:00
87% 22°C 0mm 46% 0cm 18° 35°C 0mm 3.1kPa 24135m 9.9m/s 4.4m/s
18:00
88% 22°C 0mm 52% 0cm 4.2° 33°C 0mm 2.4kPa 24134m 6.9m/s 3.3m/s
19:00
89% 22°C 0mm 57% 0cm -9.1° 31°C 0mm 2kPa 24135m 4.6m/s 2.5m/s
20:00
92% 21°C 0mm 60% 0cm -22° 30°C 0mm 1.7kPa 24134m 3.2m/s 2.6m/s
21:00
96% 21°C 0mm 62% 0cm -33° 29°C 0mm 1.6kPa 24134m 3.4m/s 2.5m/s
22:00
99% 21°C 0mm 62% 0cm -43° 29°C 0mm 1.5kPa 24134m 3.4m/s 2.4m/s
23:00
99% 21°C 0mm 63% 0cm -50° 29°C 0mm 1.5kPa 24134m 3.5m/s 2.5m/s
Tue, May 26 Sunrise 05:19 Sunset 18:21
24:00
99% 21°C 0mm 62% 0cm -51° 29°C 0mm 1.5kPa 24135m 4m/s 2.4m/s
01:00
99% 21°C 0mm 60% 0cm -48° 29°C 0mm 1.6kPa 24134m 4.4m/s 2.2m/s
02:00
99% 21°C 0mm 58% 0cm -40° 30°C 0mm 1.8kPa 24135m 9m/s 2.9m/s
03:00
100% 21°C 0mm 57% 0cm -30° 30°C 0mm 1.9kPa 24134m 8.2m/s 3.2m/s
04:00
100% 21°C 0mm 61% 0cm -18° 29°C 0mm 1.6kPa 24135m 3.1m/s 2.2m/s
05:00
100% 21°C 0mm 64% 0cm -4.9° 29°C 0mm 1.4kPa 24134m 2.8m/s 2.1m/s
06:00
100% 22°C 0mm 66% 0cm 8.4° 28°C 0mm 1.3kPa 24134m 3.7m/s 2.4m/s
07:00
100% 22°C 0mm 59% 0cm 22° 31°C 0mm 1.8kPa 24135m 5.5m/s 2.2m/s
08:00
100% 22°C 0mm 52% 0cm 36° 33°C 0mm 2.4kPa 24134m 7.7m/s 2.8m/s
09:00
100% 21°C 0mm 45% 0cm 50° 35°C 0mm 3kPa 24135m 8.3m/s 3.8m/s
10:00
100% 21°C 0mm 40% 0cm 64° 36°C 0mm 3.6kPa 24134m 7.3m/s 4m/s
11:00
100% 20°C 0mm 37% 0cm 78° 38°C 0mm 4kPa 24134m 7.6m/s 4.9m/s
12:00
99% 20°C 0mm 34% 0cm 86° 39°C 0mm 4.5kPa 24134m 7.7m/s 5.6m/s
13:00
99% 20°C 0mm 32% 0cm 73° 39°C 0mm 4.8kPa 24135m 7.3m/s 5.8m/s
14:00
97% 19°C 0mm 31% 0cm 59° 40°C 0mm 5kPa 24134m 6.7m/s 5.6m/s
15:00
94% 19°C 0mm 30% 0cm 45° 40°C 0mm 5kPa 24135m 6.7m/s 5.6m/s
16:00
92% 19°C 0mm 32% 0cm 31° 39°C 0mm 4.8kPa 24134m 6.6m/s 5.2m/s
17:00
93% 20°C 0mm 37% 0cm 18° 37°C 0mm 4kPa 24135m 8.2m/s 5.3m/s
18:00
94% 20°C 0mm 44% 0cm 4.3° 34°C 0mm 3kPa 24134m 11m/s 5.4m/s
19:00
95% 20°C 0mm 48% 0cm -9° 33°C 0mm 2.5kPa 24134m 9m/s 3.2m/s
20:00
96% 21°C 0mm 53% 0cm -22° 31°C 0mm 2.1kPa 24134m 2.8m/s 1.8m/s
21:00
97% 20°C 0mm 56% 0cm -33° 30°C 0mm 1.9kPa 24135m 3.5m/s 1.9m/s
22:00
98% 20°C 0mm 53% 0cm -43° 31°C 0mm 2.1kPa 24135m 7.9m/s 2.4m/s
23:00
97% 20°C 0mm 52% 0cm -49° 31°C 0mm 2.2kPa 24134m 7.5m/s 2.6m/s
Wed, May 27 Sunrise 05:19 Sunset 18:22
24:00
97% 20°C 0mm 49% 0cm -51° 32°C 0mm 2.5kPa 24135m 12m/s 4.3m/s
01:00
96% 20°C 0mm 51% 0cm -48° 32°C 0mm 2.3kPa 24134m 12m/s 5m/s
02:00
94% 21°C 0mm 47% 0cm -40° 34°C 0mm 2.8kPa 24134m 9.8m/s 4.6m/s
03:00
92% 21°C 0mm 43% 0cm -30° 35°C 0mm 3.3kPa 24135m 7.8m/s 4.1m/s
04:00
90% 21°C 0mm 39% 0cm -18° 37°C 0mm 3.8kPa 24135m 5.9m/s 3.6m/s
05:00
91% 20°C 0mm 36% 0cm -4.9° 38°C 0mm 4.2kPa 24135m 5.7m/s 4m/s
06:00
91% 20°C 0mm 34% 0cm 8.5° 39°C 0mm 4.6kPa 24135m 5.4m/s 4.3m/s
07:00
92% 20°C 0mm 31% 0cm 22° 40°C 0mm 5kPa 24135m 5.2m/s 4.7m/s
08:00
90% 20°C 0mm 34% 0cm 36° 39°C 0mm 4.6kPa 24135m 5.4m/s 3.9m/s
09:00
87% 20°C 0mm 36% 0cm 50° 38°C 0mm 4.3kPa 24135m 5.6m/s 3.1m/s
10:00
85% 21°C 0mm 38% 0cm 64° 37°C 0mm 3.9kPa 24135m 5.7m/s 2.3m/s
11:00
83% 22°C 0mm 49% 0cm 77° 35°C 0mm 2.8kPa 24135m 5.3m/s 2.3m/s
12:00
80% 23°C 0mm 60% 0cm 86° 32°C 0mm 1.9kPa 24135m 4.9m/s 2.4m/s
13:00
78% 24°C 0mm 71% 0cm 73° 30°C 0mm 1.2kPa 24135m 4.4m/s 2.4m/s
14:00
65% 23°C 0mm 69% 0cm 59° 29°C 0mm 1.3kPa 24135m 3.6m/s 2.3m/s
15:00
51% 22°C 0mm 66% 0cm 45° 29°C 0mm 1.3kPa 24135m 2.8m/s 2.2m/s
16:00
38% 21°C 0mm 64% 0cm 31° 29°C 0mm 1.4kPa 24135m 2m/s 2m/s
17:00
35% 21°C 0mm 64% 0cm 18° 28°C 0.02mm 1.4kPa 24135m 2m/s 2m/s
18:00
32% 21°C 0mm 63% 0cm 4.4° 28°C 0.04mm 1.4kPa 24135m 2m/s 2m/s
19:00
29% 20°C 0mm 62% 0cm -8.9° 28°C 0.06mm 1.4kPa 24135m 2m/s 1.9m/s
How to read: these inputs help produce the derived score; they are not requirements by themselves.

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