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Rule Fog Hunter

Sapa - Fog Hunter - Vietnam

Sa Pa, Lào Cai 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 Spread6.1°C
Visibility21268 (Clear)
Relative Humidity69%
Wind Speed1.5m/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 75 hours
AND logic: all conditions required
Meets requirement
Misses requirement
Time
Asia/Bangkok
Fog Probability
≥ 75.0%
Mon, May 18
11:000%
12:000%
13:000%
14:000%
15:000%
16:000%
17:000%
18:000%
19:000%
20:000%
21:000%
22:000%
23:000%
Tue, May 19
24:000%
01:000%
02:000%
03:000%
04:000%
05:000%
06:000%
07:000%
08:000%
09:000%
10:000%
11:000%
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13:000%
14:000%
15:000%
16:000%
17:000%
18:000%
19:000%
20:000%
21:000%
22:000%
23:000%
Wed, May 20
24:000%
01:000%
02:000%
03:000%
04:000%
05:000%
06:000%
07:000%
08:000%
09:000%
10:000%
11:000%
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13:000%
14:000%
15:000%
16:000%
17:000%
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19:000%
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22:000%
23:000%
Thu, May 21
24:000%
01:000%
02:000%
03:000%
04:000%
05:000%
06:000%
07:000%
08:000%
09:000%
10:000%
11:000%
12:000%
13:000%
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
Mon, May 18 Sunrise 05:23 Sunset 18:38
15:00
2% 20°C 0mm 69% 0cm 48° 26°C 0.88mm 1kPa 21268m 1.6m/s 1.5m/s
16:00
1% 20°C 0mm 73% 0cm 35° 25°C 1.4mm 0.88kPa 20895m 1.4m/s 1m/s
17:00
1% 20°C 0mm 77% 0cm 21° 25°C 1.6mm 0.72kPa 24134m 1.3m/s 0.85m/s
18:00
1% 20°C 0mm 86% 0cm 7.7° 23°C 1.7mm 0.38kPa 24135m 1.1m/s 1.1m/s
19:00
1% 19°C 0mm 90% 0cm -5.3° 20°C 1.8mm 0.24kPa 24134m 1.3m/s 1.5m/s
20:00
6% 18°C 0mm 92% 0cm -18° 19°C 0.75mm 0.18kPa 22770m 1.1m/s 1.4m/s
21:00
11% 18°C 0mm 91% 0cm -29° 19°C 1.1mm 0.2kPa 24134m 1.3m/s 1.7m/s
22:00
16% 18°C 0mm 91% 0cm -39° 19°C 1.3mm 0.21kPa 24134m 1.5m/s 1.9m/s
23:00
12% 18°C 0.01mm 95% 0cm -45° 19°C 2.6mm 0.1kPa 3299m 1.2m/s 1.6m/s
Tue, May 19 Sunrise 05:23 Sunset 18:38
24:00
8% 18°C 0mm 95% 0cm -48° 19°C 3.4mm 0.11kPa 10732m 1.2m/s 1.4m/s
01:00
4% 18°C 0mm 96% 0cm -46° 19°C 4.8mm 0.09kPa 10524m 1m/s 1.2m/s
02:00
3% 18°C 0mm 97% 0cm -39° 18°C 1.9mm 0.06kPa 16309m 1.1m/s 1.3m/s
03:00
1% 18°C 0mm 95% 0cm -29° 19°C 2.4mm 0.1kPa 17394m 1m/s 1.1m/s
04:00
0% 18°C 0mm 95% 0cm -18° 19°C 2.9mm 0.1kPa 16469m 1m/s 1.1m/s
05:00
0% 18°C 0mm 96% 0cm -5.8° 18°C 3.8mm 0.08kPa 4102m 0.8m/s 0.94m/s
06:00
0% 18°C 0mm 97% 0cm 7.2° 19°C 5.2mm 0.06kPa 4201m 0.9m/s 1m/s
07:00
0% 19°C 0mm 95% 0cm 21° 20°C 5.9mm 0.13kPa 12411m 1.4m/s 0.86m/s
08:00
2% 20°C 0mm 92% 0cm 34° 21°C 1mm 0.19kPa 4755m 1.8m/s 1.2m/s
09:00
5% 20°C 0mm 90% 0cm 48° 22°C 2.4mm 0.28kPa 4169m 1.8m/s 1.3m/s
10:00
7% 20°C 0mm 84% 0cm 62° 23°C 3.3mm 0.46kPa 20642m 1.8m/s 1.6m/s
11:00
9% 20°C 0mm 78% 0cm 76° 24°C 4.2mm 0.68kPa 21072m 1.8m/s 1.8m/s
12:00
10% 20°C 0mm 70% 0cm 87° 25°C 4.7mm 0.98kPa 24134m 1.9m/s 2m/s
13:00
12% 19°C 0mm 65% 0cm 76° 26°C 4.9mm 1.2kPa 24134m 1.8m/s 2.1m/s
14:00
15% 19°C 0mm 64% 0cm 62° 26°C 0.25mm 1.2kPa 24134m 1.8m/s 2.1m/s
15:00
18% 19°C 0mm 63% 0cm 48° 26°C 0.5mm 1.3kPa 19748m 1.8m/s 1.7m/s
16:00
21% 19°C 0mm 62% 0cm 35° 26°C 0.81mm 1.3kPa 24135m 1.4m/s 1.1m/s
17:00
23% 20°C 0mm 75% 0cm 21° 25°C 1.1mm 0.79kPa 15592m 1.5m/s 0.96m/s
18:00
26% 20°C 0mm 86% 0cm 7.8° 23°C 1.3mm 0.4kPa 24134m 1.1m/s 1m/s
19:00
28% 19°C 0mm 90% 0cm -5.2° 21°C 1.6mm 0.24kPa 24134m 1.4m/s 1.6m/s
20:00
33% 19°C 0mm 92% 0cm -18° 20°C 0.19mm 0.18kPa 24134m 1.3m/s 1.7m/s
21:00
37% 18°C 0mm 94% 0cm -29° 19°C 0.63mm 0.13kPa 21434m 1.4m/s 1.8m/s
22:00
42% 18°C 0mm 95% 0cm -38° 19°C 1.4mm 0.1kPa 16497m 1.5m/s 1.8m/s
23:00
37% 18°C 0mm 96% 0cm -45° 19°C 1.6mm 0.09kPa 16249m 1.5m/s 1.9m/s
Wed, May 20 Sunrise 05:23 Sunset 18:38
24:00
33% 18°C 0mm 97% 0cm -48° 18°C 2.1mm 0.07kPa 15227m 1.1m/s 1.4m/s
01:00
28% 18°C 0mm 97% 0cm -45° 18°C 2.6mm 0.05kPa 2649m 1.3m/s 1.5m/s
02:00
19% 18°C 0mm 98% 0cm -39° 18°C 1.4mm 0.05kPa 3771m 1.2m/s 1.4m/s
03:00
10% 18°C 0mm 96% 0cm -29° 18°C 1.9mm 0.08kPa 24134m 1.1m/s 1.2m/s
04:00
1% 18°C 0mm 96% 0cm -18° 18°C 2.2mm 0.09kPa 24135m 1m/s 1.2m/s
05:00
1% 18°C 0mm 96% 0cm -5.7° 18°C 2.4mm 0.09kPa 24135m 1.2m/s 1.3m/s
06:00
0% 18°C 0mm 96% 0cm 7.3° 18°C 2.4mm 0.09kPa 9838m 1.2m/s 1.4m/s
07:00
0% 19°C 0mm 92% 0cm 21° 20°C 2.6mm 0.18kPa 12846m 1m/s 0.59m/s
08:00
1% 20°C 0mm 89% 0cm 34° 22°C 0.88mm 0.28kPa 5577m 1.5m/s 0.95m/s
09:00
3% 20°C 0mm 86% 0cm 48° 23°C 1.7mm 0.4kPa 10289m 1.4m/s 1.1m/s
10:00
4% 20°C 0mm 81% 0cm 62° 24°C 2.4mm 0.55kPa 10216m 1.5m/s 1.3m/s
11:00
5% 20°C 0mm 79% 0cm 76° 24°C 3.3mm 0.64kPa 18427m 1.5m/s 1.4m/s
12:00
5% 20°C 0mm 70% 0cm 88° 25°C 3.9mm 0.99kPa 24135m 1.5m/s 1.6m/s
13:00
6% 19°C 0mm 62% 0cm 76° 27°C 4.3mm 1.3kPa 24134m 1.5m/s 1.8m/s
14:00
14% 18°C 0mm 60% 0cm 62° 27°C 0.31mm 1.4kPa 21823m 1.5m/s 1.7m/s
15:00
21% 19°C 0mm 61% 0cm 48° 27°C 0.69mm 1.4kPa 24134m 1.5m/s 1.5m/s
16:00
29% 18°C 0mm 62% 0cm 35° 26°C 1mm 1.3kPa 21643m 1.4m/s 1.3m/s
17:00
31% 20°C 0mm 72% 0cm 21° 25°C 1.5mm 0.89kPa 18960m 1.5m/s 1m/s
18:00
33% 20°C 0mm 87% 0cm 7.9° 22°C 2.1mm 0.36kPa 21887m 0.8m/s 0.82m/s
19:00
35% 19°C 0mm 92% 0cm -5.1° 20°C 2.3mm 0.18kPa 24134m 1.4m/s 1.7m/s
20:00
38% 18°C 0mm 93% 0cm -17° 19°C 0.06mm 0.16kPa 24135m 1.4m/s 1.8m/s
21:00
40% 18°C 0mm 95% 0cm -29° 19°C 0.5mm 0.12kPa 24135m 1.3m/s 1.7m/s
22:00
43% 18°C 0mm 94% 0cm -38° 19°C 0.75mm 0.13kPa 24134m 1.3m/s 1.7m/s
23:00
41% 18°C 0mm 95% 0cm -45° 19°C 1mm 0.1kPa 10863m 1.4m/s 1.8m/s
Thu, May 21 Sunrise 05:23 Sunset 18:39
24:00
38% 18°C 0mm 96% 0cm -48° 19°C 1.1mm 0.07kPa 15200m 1.4m/s 1.8m/s
01:00
36% 18°C 0mm 97% 0cm -45° 19°C 1.2mm 0.07kPa 15130m 1.3m/s 1.7m/s
02:00
27% 20°C 0mm 88% 0cm -39° 22°C 1.2mm 0.31kPa 16752m 1.7m/s 1.6m/s
03:00
19% 22°C 0mm 79% 0cm -29° 25°C 1.1mm 0.67kPa 18374m 2m/s 1.6m/s
04:00
10% 23°C 0mm 71% 0cm -18° 29°C 1.1mm 1.1kPa 19997m 2.3m/s 1.6m/s
05:00
8% 23°C 0.07mm 69% 0cm -5.6° 29°C 1.8mm 1.3kPa 19874m 2.3m/s 1.7m/s
06:00
5% 23°C 0.15mm 67% 0cm 7.4° 30°C 2.5mm 1.4kPa 19751m 2.3m/s 1.7m/s
07:00
3% 23°C 0.22mm 66% 0cm 21° 30°C 3.2mm 1.5kPa 19629m 2.3m/s 1.8m/s
08:00
3% 24°C 0.15mm 69% 0cm 34° 30°C 3mm 1.3kPa 17529m 2.7m/s 1.7m/s
09:00
2% 24°C 0.07mm 73% 0cm 48° 29°C 2.9mm 1.1kPa 15429m 3.1m/s 1.6m/s
10:00
2% 24°C 0mm 76% 0cm 62° 29°C 2.8mm 0.93kPa 13329m 3.5m/s 1.5m/s
11:00
2% 24°C 0.16mm 82% 0cm 76° 28°C 3.7mm 0.66kPa 16931m 2.9m/s 1.3m/s
12:00
3% 24°C 0.31mm 88% 0cm 88° 26°C 4.7mm 0.41kPa 20533m 2.3m/s 1.2m/s
13:00
3% 24°C 0.47mm 93% 0cm 76° 25°C 5.7mm 0.21kPa 24135m 1.6m/s 1.1m/s
14:00
7% 23°C 0.32mm 94% 0cm 62° 24°C 4.3mm 0.17kPa 24135m 1.4m/s 0.96m/s
How to read: these inputs help produce the derived score; they are not requirements by themselves.

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