Wind Analysis for Any Plot in India

Annual mean wind speed, prevailing direction, and seasonal breakdown — at 250m resolution, terrain-corrected. Uses the Global Wind Atlas v3 (DTU / World Bank) with ERA5-Land multi-year trend.

What wind speed tells you about a piece of land

Wind is one of the most underused parameters in pre-purchase land assessment. It affects ventilation, structural cost, agricultural suitability, and — for larger plots — renewable energy potential. The numbers in your result card answer three practical questions.

Natural ventilation and building orientation

A plot with a 4–6 m/s annual mean and a consistent prevailing direction gives a structural engineer enough to design natural cross-ventilation without mechanical cooling. The rule is straightforward: orient the building so the longer facades face the prevailing wind direction (typically SW in monsoon, NE in winter in peninsular India). Inlet openings on the windward face and exhaust openings on the leeward face create a pressure difference that draws air through. In Hyderabad, Bengaluru, and Pune — cities with 4–5 m/s annual means — this reduces cooling loads by 15–30% in a well-designed building versus a randomly oriented one.

A site with a very low annual mean (below 2 m/s) or a highly variable direction is harder to design for passively. Mechanical ventilation becomes the default, which is fine but costs more to run.

Structural wind loads — and why annual mean is not the design number

IS 875 Part 3 (Wind Loads on Buildings and Structures) uses the basic wind speed Vb — the 3-second gust speed at 10m height with a 50-year return period. This is a very different number from annual mean wind speed. A site with a calm 3.5 m/s annual mean can still sit inside a 44 m/s IS 875 zone if the region experiences occasional severe storms.

The annual mean in this result is useful for ventilation and energy planning. For structural design, always use the IS 875 Part 3 wind speed map for the specific district, and apply gust factor, terrain category, and topography factor corrections as required. Your structural engineer does this calculation — the annual mean is not their input.

Agriculture and horticulture

Wind has opposite effects on crops depending on intensity. Moderate wind (2–5 m/s) promotes evapotranspiration and reduces disease by drying leaf surfaces — generally positive. Strong sustained winds above 8–10 m/s cause physical damage: stem lodging in cereals, fruit drop in orchards, excessive soil moisture loss in sandy soils. Coastal plots in Tamil Nadu and Andhra Pradesh facing the Bay of Bengal need windbreak planning if monsoon speeds exceed 8 m/s regularly. The seasonal breakdown in your result card identifies which season, if any, creates this risk.

Wind energy screening (10+ acres)

India’s commercial wind energy threshold is approximately 6–7 m/s at 80–100m hub height. The annual mean at 50m height in your result is a first filter. A site clearing 5 m/s at 50m typically clears 6–7 m/s at 80m due to wind shear. Sites below 4 m/s annual mean at surface level are generally not viable for commercial wind power in India’s current tariff environment without strong specific terrain effects (ridge acceleration, funnel channelling). The Global Wind Atlas 250m is the data layer IRENA and the World Bank publish as the standard for wind resource screening globally.

The Beaufort reference for day-to-day understanding

0–2 m/s (Calm to Light air): Smoke rises vertically. No wind noticeable. Buildings need forced or assisted ventilation.
2–4 m/s (Light to Gentle breeze): Leaves rustle. Good for passive ventilation through openings. Comfortable for outdoor activity.
4–6 m/s (Gentle to Moderate breeze): Branches move. Optimal for natural cross-ventilation in buildings. Most comfortable wind range for agriculture.
6–9 m/s (Moderate to Fresh breeze): Small trees sway. Wind-noise through windows. Structural detailing for cladding and fixings starts to matter above 8 m/s.
9–12 m/s (Fresh to Strong breeze): Large branches move. Umbrella use difficult. Site requires windbreak planning for horticulture. Rooftop fixings need formal design.
Above 12 m/s (Near gale+): Twigs break. Sustained wind at this level is rare in India except in cyclone-prone coastal zones and high-altitude passes.

What do these numbers mean?

Your result card contains two layers of data: a high-resolution 10-year wind climate from the Global Wind Atlas, and a 15-year annual trend from ERA5-Land. Here is how to read each metric.

Annual Mean Wind Speed (m/s)

The time-averaged wind speed at 50m height above ground, averaged over the Global Wind Atlas climatological period (2008–2017). This is the industry standard for resource characterisation — not the surface reading and not a recent-year snapshot.

Reading guide: Below 3 m/s = low ventilation potential. 3–5 m/s = good for passive ventilation. 5–7 m/s = viable for small wind turbines. Above 7 m/s = commercial wind energy zone.

Prevailing Direction

The compass direction from which wind most frequently arrives at the site, as a 10-year average. In meteorology, SW wind means the wind comes FROM the south-west. A SW prevailing direction means the windward face of your building should face south-west to capture breeze or bear the load.

India pattern: Most of peninsular India has a SW prevailing direction (monsoon dominates annual hours). Northern and eastern India split between SW monsoon and NE winter winds. The annual average may show a diagonal (SSW, SSE) reflecting both seasons.

Seasonal Breakdown

Wind speed and direction averaged for each of the four standard meteorological seasons: Winter (Dec–Feb), Pre-monsoon (Mar–May), SW Monsoon (Jun–Aug), and Retreating Monsoon (Sep–Nov). The seasonal split often reveals a stronger monsoon component that dominates the annual average.

What to look for: Does any season exceed 8 m/s? If so, agricultural wind-damage planning may be needed. Does direction flip by more than 90° between seasons? If so, the building orientation optimum is for the dominant season.

Trend Label & Annual Chart

The ERA5-Land annual mean wind speed from 2010 to the most recent complete year, and a trend classification: Strengthening (significant upward trend), Stable (change within ±10% of mean), or Weakening (significant downward trend). ERA5-Land is at ~9km resolution — good for trend, not for parcel-level terrain.

Why it matters: A weakening trend in a coastal agricultural zone may mean more still, humid conditions — higher disease risk. A strengthening trend in a high-wind zone may mean more cladding fatigue on older structures.

Why wind direction reverses every six months

India sits at the convergence of two opposing circulation systems. Understanding these four seasons is the key to interpreting the seasonal breakdown in your result card.

DJF

Winter · Dec–Feb

The North-East monsoon dominates. Continental high pressure over central Asia pushes dry, cool air southward across the Indo-Gangetic plain and down the east coast. Prevailing winds are from the north-east or north. The Bay of Bengal receives rainfall during this period (Tamil Nadu, south Andhra coast) as moist NE winds pick up moisture over the sea. Wind speeds are generally low across the interior — typically 1–3 m/s. The most stable, calm season for most of India.

MAM

Pre-monsoon · Mar–May

Land heats rapidly as the sun moves northward. Convective activity produces localised strong winds, dust storms (loo in the north), and pre-monsoon squalls (Nor’westers in West Bengal and Assam). The Inter-Tropical Convergence Zone migrates north, and wind patterns become unstable and variable. Speed can spike to 8–12 m/s during thunderstorm events but is calmer between events. Direction shifts from northerly to variable south/south-westerly as the monsoon approaches.

JJA

SW Monsoon · Jun–Aug

The South-West monsoon is India’s defining wind event. Intense solar heating of the Tibetan Plateau creates a thermal low that pulls moisture-laden air from the Arabian Sea and Bay of Bengal across the entire subcontinent. Winds arrive from the south-west at 4–8 m/s on the west coast, intensify across the Deccan, and weaken as they reach the north. This is when wind energy potential peaks — Kerala, Karnataka, Tamil Nadu, and Maharashtra coasts see sustained winds of 6–10 m/s. September is grouped separately into SON because by late August the monsoon begins its retreat from the north-west, and the circulation is transitioning rather than fully established.

SON

Retreating Monsoon · Sep–Nov

The South-West monsoon withdraws progressively from north-west India (September) to the south-east (December). As the SW flow weakens, north-easterly winds begin to establish over the Bay of Bengal, reversing the coastal wind direction. The east coast (Andhra Pradesh, Tamil Nadu, Puducherry) receives its main rainfall during October–November from the North-East monsoon. Wind speeds drop significantly as the large-scale circulation weakens, making SON the transition period with the most variable direction readings in the result card.

Why direction matters for buildings and farms: If your plot’s result shows a >90° direction shift between JJA (typically SW) and DJF (typically NE), your windward face changes seasonally. For natural ventilation, orient openings toward the dominant summer direction (usually SW). For windbreaks protecting crops, plant them on the side facing the season with the highest speed.

India's wind resource geography

India's wind resource is strongly seasonal and regionally concentrated. Understanding where your plot sits in the national picture helps interpret the result.

Region	Typical Annual Mean	Dominant Season	Key Characteristic
Rajasthan, Gujarat, Kutch	5–8 m/s	Summer + Monsoon	Thermal gradient winds from the Thar. India’s largest wind power installed capacity. Suited for utility-scale wind and agri-solar-wind hybrid projects.
Tamil Nadu coast (Muppandal belt)	6–9 m/s	SW Monsoon · Jun–Aug (JJA peak)	Bay of Bengal onshore flow + funnel terrain near the southern tip. India’s most wind-dense coastal zone. Strong seasonal variation.
AP & Karnataka coast	4–6 m/s	SW Monsoon · Jun–Aug (JJA peak)	Sustained southwest monsoon onshore. Good natural ventilation for coastal residential plots. Check JJA and SON seasonal bars in your result.
Peninsular interior (Telangana, Karnataka, Maharashtra)	3–5 m/s	Monsoon	Moderate wind, consistent direction. Good passive ventilation potential. Not viable for commercial wind energy without specific ridge or gap terrain.
Indo-Gangetic Plain (UP, Bihar, Punjab, Haryana)	2–4 m/s	Monsoon + Winter westerlies	Low annual mean. High dust-loading in pre-monsoon (April–June). Building orientation still matters for natural cooling in hot summers.
Northeast (Assam, Meghalaya, Sikkim)	1.5–3.5 m/s	Monsoon (highly variable)	Sheltered by Himalayan ranges for much of the year. Dense topography creates channelling in valleys. Results vary sharply with micro-site location.
Kerala & Konkan coast	2–4 m/s	Monsoon (heavy but short)	High monsoon intensity for 4 months, calm rest of year. Heavy rainfall co-occurs with wind. Building waterproofing more critical than wind loading.

Source: Global Wind Atlas v3, DTU Wind Energy / World Bank Group (2023). Annual means at 50m height, 10-year climatology 2008–2017.

How the analysis works

Two datasets, one result card. High-resolution terrain-corrected climate from GWA; long-term trend from ERA5-Land reanalysis.

You mark the site

Draw the plot boundary, drop a pin, or type an address. We extract the centroid coordinates. Wind resource varies meaningfully over ridge–valley distances (250m resolution), so the specific location matters more here than for regional parameters like air quality or night lights.

GWA lookup at 250m

The Global Wind Atlas v3 data is queried at the centroid. GWA uses a downscaling chain: ERA5 global reanalysis → WRF mesoscale model at 3km → WindSim CFD model at 250m with digital terrain and roughness inputs. The 250m output captures ridge acceleration, valley channelling, and slope effects that coarser products miss.

ERA5-Land trend (2010–present)

The annual mean wind speed for each year from 2010 to the most recent complete year is extracted from the ERA5-Land reanalysis (~9km) at the same location. A linear trend is fitted and classified as Strengthening, Stable, or Weakening based on the slope relative to the period mean.

Methodology and data sources

Primary: Global Wind Atlas v3 (GWA)

The Global Wind Atlas v3 is produced by DTU Wind Energy (Technical University of Denmark) in partnership with the World Bank Group and ESMAP. It combines ERA5 reanalysis as boundary conditions, WRF (Weather Research and Forecasting) mesoscale modelling at ~3km, and WindSim CFD downscaling to 250m horizontal resolution. The climatological period is 2008–2017 (10 years). Output parameters include mean wind speed and wind power density at multiple hub heights (10m, 50m, 100m, 150m, 200m), prevailing direction, Weibull parameters A and k, and seasonal breakdowns by standard meteorological season.

License: CC BY 4.0 — free to use commercially with attribution. Published by the World Bank Group / ESMAP.

DTU Wind Energy / World Bank250m horizontal resolution2008–2017 climatologyCC BY 4.0

Trend data: ERA5-Land (ECMWF/Copernicus)

ERA5-Land is produced by ECMWF under the Copernicus Climate Change Service. It is a reanalysis product that combines model data with observations covering January 1950 to the present, updated with approximately 3-month latency. Horizontal resolution: ~9km (0.1° × 0.1°). The wind speed variable used is u10 and v10 (10m height winds), converted to resultant speed. This is the standard ERA5 surface wind layer — ERA5-Land provides enhanced spatial detail for land surface variables; wind at 10m is one of the core variables.

ECMWF ERA5-Land~9km resolution2010 – present (annual)Copernicus Climate Data Store

How we classify results

Good (Comfortable Winds): 3–6 m/s annual mean. Optimal for passive ventilation; agriculture-friendly; good for distributed wind turbines.
Moderate (Light Winds): 1.5–3 m/s. Buildings need design assistance for natural ventilation. Not viable for wind energy without specific terrain gains.
Moderate (Fresh Winds): 6–9 m/s. Structural wind loading starts to matter. Agricultural windbreak planning recommended. Viable for commercial wind energy.
Poor / Severe (Strong Winds): Above 9 m/s annual mean. Significant structural considerations. Specialist engineering required for any permanent structure.

Limitations

GWA is a climatological average, not a recent measurement. The 2008–2017 period may not reflect recent interannual variability. The ERA5-Land trend layer supplements this.
250m is not the same as a met mast measurement. GWA is a modelled product; terrain-induced turbulence, vegetation roughness changes, and local obstruction effects (buildings, tree rows) are not captured at sub-250m scale. A bankable wind energy assessment requires on-site measurements.
Height correction. GWA outputs at 50m. If your application needs wind speed at hub height (80m, 100m, 150m), apply the power law: V(h₂)/V(h₁) = (h₂/h₁)^α where α ≈ 0.14 for open land (terrain category II) to 0.28 for rough terrain. Consult GWA’s full output for Weibull parameters at higher hub heights.
Cyclone-prone coastal zones. The annual mean substantially underrepresents risk in NDMA-designated cyclone-prone coastal districts. IS 875 Part 3 cyclonic wind zones are the authoritative reference for structural design in those areas.

Frequently Asked Questions

What does prevailing wind direction mean for my plot?

Prevailing direction is where wind most frequently comes from over the year. It affects two practical decisions: building orientation (windows on the windward face improve natural ventilation; solid walls on the windward face reduce structural loads and dust ingress) and planting (windbreaks on the windward side protect sensitive crops or buildings). In most of peninsular India, the monsoon SW wind dominates annual hours. Northern and eastern India split between SW monsoon and NE winter winds, producing a diagonal annual average.

Does wind speed affect construction cost?

Indirectly, yes. IS 875 Part 3 governs wind loads, and construction in a higher design wind speed zone (say 44 m/s versus 33 m/s) requires heavier structural connections, more robust cladding fixings, and larger sections for exposed elements. The annual mean wind speed in this result is not the IS 875 design figure — always use the IS 875 Part 3 wind speed map for your district. The annual mean is for ventilation and energy planning. The IS 875 design wind speed for the same location can be 8–10× the annual mean because it represents a rare extreme event.

Why does Rajasthan have higher wind speeds than the northeast?

Three factors: the Thar Desert creates strong thermal gradients that drive persistent westerly and south-westerly winds, especially in summer. The flat terrain of western Rajasthan and Gujarat allows wind to accelerate without topographic obstruction. And the region sits in the path of synoptic-scale low-pressure systems tracking from the Arabian Sea during monsoon. The northeastern states sit in the shelter of the Himalayan ranges for much of the year, and the dense topography creates channelling and blocking effects that reduce mean speeds significantly.

What is the difference between GWA 250m and ERA5-Land?

GWA uses a downscaling chain — ERA5 drives WRF at 3km, then WindSim CFD at 250m — that captures ridge acceleration, valley channelling, and local terrain effects at parcel scale. ERA5-Land is the direct reanalysis product at ~9km without the microscale step, good for long-term trend analysis but not for parcel-level terrain differences. This tool uses GWA for the headline wind climate figure (more accurate, terrain-aware) and ERA5-Land for the annual trend (longer time series, consistent methodology year over year).

Can I use this for a wind energy project?

GWA 250m is the appropriate first screen for wind energy siting — it is the dataset IRENA and the World Bank publish as the global standard for resource assessment. For a bankable wind energy feasibility report, you need a minimum 12-month met mast or lidar campaign to establish P50/P90 yield estimates. GWA tells you whether the site is worth that investment. Mean wind speeds below 5 m/s at 50m height are generally not viable for utility-scale projects in India's current tariff environment without specific terrain gains (ridge, funnel, or escarpment effects).

Why does my coastal plot show stronger monsoon winds than my inland plot?

The Indian summer monsoon delivers its strongest sustained winds within roughly 100–200 km of the west and east coasts. The Bay of Bengal and Arabian Sea branches feed onshore flow that can sustain 7–9 m/s in coastal Tamil Nadu, Andhra Pradesh, and Karnataka from June–September. Inland, the wind decelerates as the marine layer weakens and land friction increases. The 250m terrain-corrected GWA captures this coastal acceleration effect at parcel resolution, unlike raw ERA5 reanalysis.

What wind speed is safe for rooftop solar panels?

Rooftop solar panels are typically rated to withstand 170–200 km/h (47–56 m/s) wind speed — well above any annual mean you would encounter in India. The structural concern is not the annual mean but rare extreme events: cyclones in coastal zones, severe thunderstorm downbursts, or hail. For rooftop solar, the relevant design standard is the panel manufacturer's wind load certification and IS 875 Part 3 for the mounting structure. The annual mean wind speed in this result is not a risk indicator for solar panel safety.