Greenhouse Screen Selection Case Study-China

Parameter

Value

Notes

Annual total solar radiation

5,760–5,940 MJ/m²

Class B (very rich resource area)

Peak summer noon irradiance

1,000–1,150 W/m²

Estimated for extreme high temperatures (37.1–40.6°C)

Annual sunshine duration

2,140–2,797 h

Average sunshine percentage:55.3–62.5%;~45% in July–August

Cloudy day ratio

35–40% annually;45–50% (Jun–Aug)

Derived from cloud cover data (22.3% cloudy,21.2% partly cloudy in summer)

Parameter

Value

Notes

Winter nighttime minimum temperature

Extreme:-25.6°C (historical);
Typical:-12~-16°C,3-5 days/year

Summer high-temperature days (≥35°C)

3-5 days/year;Extreme:37.1-40.6°C

Diurnal temperature range

10-15°C annually;12-18°C in summer

Calculated from monthly averages(Jan: -2.48°C, Jul: 25.11°C)

Parameter

Value

Notes

Annual average relative humidity (RH)

55–60%

Monthly:Jan 54%,Jul 77%,Aug 84%

High-humidity days (RH≥80%,rainy season)

25–35 days/year (Jun–Aug)

Annual precipitation:785–842.6 mm,concentrated in Jul–Aug

Condensation risk level

Moderately high

High humidity + large diurnal range → nighttime condensation risk

Parameter

Value

Notes

Annual maximum wind speed

20–25 m/s;Gusts:25–30 m/s

Average wind speed:3.3 m/s;Winter north wind:3.7 m/s

Prevailing wind direction

North (winter);Southeast (spring/summer)

Typhoon impact

~1 event every 2–3 years (peripheral influence)

Hail

~0.3 days/year,concentrated in May–Jun

Often concurrent with thunderstorms and strong winds

Blizzard

1–2 events/year,Dec–Feb

Jan 2026 heavy snow:snow depth 3–8 cm