Can a wind-shear value measured in summer be applied unchanged to winter?

The short answer

A wind-shear relationship observed in summer should not automatically be applied unchanged to winter. The vertical flow relationship can vary with atmospheric conditions, surface exposure and direction. The assessment must distinguish a measured seasonal relationship from an annual assumption and show whether that distinction matters to predicted useful energy.

Describe the evidence period

Record the concurrent sensor heights, dates, valid coverage and environmental context of the measurement. Identify whether the summer record includes the direction sectors important in winter. An apparently well-fitted relationship may simply describe a narrow set of conditions.

Avoid using different measurement periods at different heights to infer seasonal shear. That confounds changes over time with changes over height and can produce a misleading transfer relationship.

Test the unsupported portion of the year

Use available longer records, additional measurements or defensible model evidence to investigate other seasons. Where the annual transfer remains uncertain, apply explicit sensitivity cases rather than copying the summer parameter without qualification.

Compare the effects on both annual generation and the season relevant to the site's loads. A project requiring winter energy may be more sensitive to the missing seasonal evidence than an annual total initially suggests.

Let decision sensitivity guide further work

If plausible seasonal transfers change the preferred tower height or the feasibility conclusion, further measurement can address a material uncertainty. If the result remains stable, the report can explain why the simpler assumption is sufficient for the current screening decision.

The handover should retain seasonal coverage, the selected transfer rule and its limitations. This provides a transparent basis for an equipment enquiry while avoiding the claim that one short seasonal campaign has established the complete annual vertical wind profile at the proposed turbine.