Rule Morning Frost

Morning Frost Forecast for Biei, Japan

Biei, Hokkaido, Japan

Biei's rolling fields create clean bands of color and isolated-tree studies, while the Blue Pond and birch woods add reflective winter subjects.

Currently

Real-time conditions

Frost Probability

Soil Temperature17.9°C

Dew Point17.0°C (high dew point)

Wind Speed2.4m/s (calm conditions)

Cloud Cover100%

Upcoming Opportunities

When all conditions match, PhotoWeather marks an opportunity window.

Times shown in Asia/Tokyo

No opportunities in the next 14 days

See which requirements block the most forecast hours below.

Most common blockers (78-hour forecast)

Time Window100% of hours
Frost Probability100% of hours
Wind Speed57% of hours

How this forecast is evaluated

See which weather signals PhotoWeather uses to identify Morning Frost conditions across Japan. The requirements and hourly values below show how those signals apply at Biei.

Explore Morning Frost conditions across Japan →

Recorded match history

Completed PhotoWeather forecast matches recorded for this exact rule at Biei during the last 365 days.

Last 30 days

recorded matching windows

Last 90 days

recorded matching windows

Last 365 days

recorded matching windows · 67% average confidence

Most frequent recorded start hour

05:00 local time, shared by 4 of 12 matches recorded in the last 365 days.

Most represented month

February, with 8 of 12 matches recorded in the last 365 days.

These figures use completed PhotoWeather MatchEvent records from the previous 365 days only. They describe recorded forecast matches, not observations, climatological probability, or a guarantee of future conditions.

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78-hour requirements breakdown

When available, the detailed table below covers only the stated 78-hour horizon (typically 72–168 hours, depending on available hourly data). Opportunity records above span the next 14 days, so this table does not explain that entire 14-day period.

What passed or failed, hour by hour

0matching hours in the next 78 hours

AND logic: all conditions required

Meets requirement

Misses requirement

Time Asia/Tokyo	Time Window Sunrise -45m to +90m	Frost Probability ≥ 60.0%	Wind Speed ≤ 1.5m/s
Sun, Jul 19
15:00	✕	0%	4.2m/s
16:00	✕	0%	4.5m/s
17:00	✕	0%	4.2m/s
18:00	✕	0%	3.6m/s
19:00	✕	0%	3.5m/s
20:00	✕	0%	2.9m/s
21:00	✕	0%	2.7m/s
22:00	✕	0%	2.4m/s
23:00	✕	0%	2.2m/s
Mon, Jul 20
24:00	✕	0%	2.3m/s
01:00	✕	0%	1.8m/s
02:00	✕	0%	1.8m/s
03:00	✕	0%	1.8m/s
04:00	✕	0%	1.5m/s
05:00	✕	0%	1.3m/s
06:00	✕	0%	1.1m/s
07:00	✕	0%	0.65m/s
08:00	✕	0%	0.84m/s
09:00	✕	0%	1.4m/s
10:00	✕	0%	2.1m/s
11:00	✕	0%	2.5m/s
12:00	✕	0%	2.6m/s
13:00	✕	0%	2.8m/s
14:00	✕	0%	3m/s
15:00	✕	0%	3.2m/s
16:00	✕	0%	3m/s
17:00	✕	0%	2.5m/s
18:00	✕	0%	2.2m/s
19:00	✕	0%	1.9m/s
20:00	✕	0%	1.2m/s
21:00	✕	0%	0.37m/s
22:00	✕	0%	0.88m/s
23:00	✕	0%	1.2m/s
Tue, Jul 21
24:00	✕	0%	0.69m/s
01:00	✕	0%	0.97m/s
02:00	✕	0%	0.75m/s
03:00	✕	0%	0.71m/s
04:00	✕	0%	1.5m/s
05:00	✕	0%	1.2m/s
06:00	✕	0%	1.2m/s
07:00	✕	0%	1.7m/s
08:00	✕	0%	2.2m/s
09:00	✕	0%	1.9m/s
10:00	✕	0%	1.7m/s
11:00	✕	0%	2.3m/s
12:00	✕	0%	2.4m/s
13:00	✕	0%	2.9m/s
14:00	✕	0%	3.1m/s
15:00	✕	0%	2.9m/s
16:00	✕	0%	3.3m/s
17:00	✕	0%	3.1m/s
18:00	✕	0%	2.8m/s
19:00	✕	0%	2.1m/s
20:00	✕	0%	1.6m/s
21:00	✕	0%	1.5m/s
22:00	✕	0%	0.68m/s
23:00	✕	0%	1.2m/s
Wed, Jul 22
24:00	✕	0%	1.1m/s
01:00	✕	0%	0.52m/s
02:00	✕	0%	0.96m/s
03:00	✕	0%	0.92m/s
04:00	✕	0%	1.5m/s
05:00	✕	0%	2m/s
06:00	✕	0%	2.5m/s
07:00	✕	0%	2.4m/s
08:00	✕	0%	2.3m/s
09:00	✕	0%	2.2m/s
10:00	✕	0%	1.8m/s
11:00	✕	0%	1.4m/s
12:00	✕	0%	1m/s
13:00	✕	0%	1.4m/s
14:00	✕	0%	1.7m/s
15:00	✕	0%	2m/s
16:00	✕	0%	1.8m/s
17:00	✕	0%	1.6m/s
18:00	✕	0%	1.4m/s
19:00	✕	0%	1.1m/s
20:00	✕	0%	0.87m/s

How to read: colored cells show whether each predicate requirement is met; highlighted rows mean the full rule matched (an opportunity).

What does Frost 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/Tokyo	Dew Point °C	Surface Temperature °C	Temperature °C	Time Window	Total Cloud Coverage %	Vapor Pressure Deficit kPa
Sun, Jul 19 Sunrise 04:06 Sunset 19:06
22:00 ☾	17°C	18°C	18°C	-	100%	0.18kPa
23:00 ☾	17°C	18°C	18°C	-	100%	0.17kPa
Mon, Jul 20 Sunrise 04:06 Sunset 19:06
24:00 ☾	17°C	18°C	18°C	-	100%	0.18kPa
01:00 ☾	17°C	18°C	19°C	-	100%	0.18kPa
02:00 ☾	17°C	18°C	18°C	-	100%	0.16kPa
03:00 ☾	17°C	18°C	19°C	-	100%	0.16kPa
04:00 ☾	17°C	18°C	18°C	-	100%	0.12kPa
05:00 ☾	18°C	18°C	18°C	-	100%	0.09kPa
06:00 ☾	18°C	18°C	18°C	-	100%	0.08kPa
07:00 ☾	18°C	18°C	19°C	-	100%	0.08kPa
08:00 ☾	19°C	18°C	20°C	-	100%	0.09kPa
09:00	19°C	18°C	21°C	-	100%	0.25kPa
10:00	20°C	18°C	22°C	-	100%	0.34kPa
11:00	20°C	18°C	22°C	-	94%	0.37kPa
12:00	20°C	18°C	23°C	-	60%	0.51kPa
13:00	20°C	18°C	24°C	-	100%	0.68kPa
14:00	19°C	18°C	24°C	-	64%	0.76kPa
15:00	19°C	19°C	24°C	-	87%	0.79kPa
16:00	19°C	19°C	24°C	-	100%	0.71kPa
17:00	20°C	19°C	23°C	-	100%	0.5kPa
18:00	20°C	19°C	22°C	-	74%	0.3kPa
19:00	18°C	19°C	20°C	-	56%	0.17kPa
20:00 ☾	18°C	19°C	19°C	-	69%	0.15kPa
21:00 ☾	17°C	19°C	18°C	-	68%	0.14kPa
22:00 ☾	17°C	18°C	18°C	-	86%	0.13kPa
23:00 ☾	17°C	18°C	18°C	-	26%	0.15kPa
Tue, Jul 21 Sunrise 04:07 Sunset 19:05
24:00 ☾	17°C	18°C	18°C	-	5%	0.15kPa
01:00 ☾	16°C	18°C	18°C	-	50%	0.15kPa
02:00 ☾	16°C	18°C	17°C	-	97%	0.16kPa
03:00 ☾	16°C	18°C	17°C	-	100%	0.17kPa
04:00 ☾	16°C	18°C	17°C	-	81%	0.15kPa
05:00 ☾	16°C	18°C	18°C	-	92%	0.18kPa
06:00 ☾	17°C	18°C	20°C	-	95%	0.3kPa
07:00 ☾	18°C	18°C	21°C	-	100%	0.42kPa
08:00 ☾	18°C	18°C	21°C	-	100%	0.52kPa
09:00	18°C	18°C	23°C	-	92%	0.74kPa
10:00	18°C	18°C	24°C	-	25%	0.94kPa
11:00	18°C	18°C	25°C	-	69%	1.1kPa
12:00	18°C	18°C	25°C	-	0%	1.1kPa
13:00	19°C	19°C	26°C	-	3%	1.2kPa
14:00	19°C	19°C	26°C	-	9%	1.2kPa
15:00	19°C	19°C	26°C	-	44%	1.1kPa
16:00	20°C	19°C	25°C	-	78%	0.89kPa
17:00	21°C	19°C	24°C	-	22%	0.65kPa
18:00	20°C	19°C	22°C	-	19%	0.35kPa
19:00	19°C	19°C	20°C	-	100%	0.2kPa
20:00 ☾	17°C	19°C	19°C	-	100%	0.19kPa
21:00 ☾	17°C	19°C	18°C	-	10%	0.21kPa
22:00 ☾	16°C	19°C	18°C	-	0%	0.22kPa
23:00 ☾	16°C	19°C	17°C	-	0%	0.21kPa
Wed, Jul 22 Sunrise 04:07 Sunset 19:04
24:00 ☾	15°C	19°C	17°C	-	1%	0.21kPa
01:00 ☾	15°C	18°C	17°C	-	0%	0.21kPa
02:00 ☾	15°C	18°C	17°C	-	0%	0.19kPa
03:00 ☾	15°C	18°C	16°C	-	0%	0.18kPa
04:00 ☾	16°C	18°C	19°C	-	2%	0.31kPa
05:00 ☾	18°C	18°C	21°C	-	3%	0.49kPa
06:00 ☾	19°C	19°C	24°C	-	4%	0.71kPa
07:00 ☾	19°C	19°C	24°C	-	10%	0.75kPa
08:00 ☾	20°C	19°C	24°C	-	16%	0.78kPa
09:00	20°C	19°C	25°C	-	21%	0.81kPa
10:00	20°C	19°C	24°C	-	17%	0.61kPa
11:00	20°C	19°C	23°C	-	13%	0.42kPa
12:00	20°C	19°C	22°C	-	9%	0.26kPa
13:00	20°C	19°C	21°C	-	16%	0.21kPa
14:00	19°C	19°C	20°C	-	23%	0.17kPa
15:00	18°C	19°C	19°C	-	30%	0.14kPa
16:00	18°C	19°C	19°C	-	29%	0.12kPa
17:00	18°C	19°C	19°C	-	27%	0.11kPa
18:00	18°C	19°C	18°C	-	26%	0.09kPa
19:00	17°C	19°C	18°C	-	38%	0.09kPa
20:00 ☾	17°C	19°C	18°C	-	49%	0.09kPa
21:00 ☾	17°C	18°C	18°C	-	61%	0.09kPa

How to read: these inputs help produce the derived score; they are not requirements by themselves.

How this forecast is made

Opportunities are threshold-based signals: PhotoWeather checks whether forecast conditions match the rules for a photography scenario. They are planning guidance, not guarantees. Forecasts can change as new model runs arrive, and confidence generally decreases farther into the forecast horizon, so recheck conditions before travelling.

The weather forecast foundation comes through Open-Meteo , which aggregates models from weather agencies. PhotoWeather applies condition-specific thresholds and derived calculations; not every condition uses every model or data input.

How opportunities work → Weather data sources →

Forecast generated

Jul 19, 2026, 12:50 PM UTC

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