Construction weather report – Description of expected weather

Norway experiences a lot of weather, and it can vary significantly within hours or days. The average conditions over several years – a description of the climate – can help us understand what to expect during the construction period of a specific project. When expected weather conditions are clearly described, it may be easier to assess whether delays are due to extraordinary circumstances or simply part of the normal climate, which could influence discussions around delays and compensation. 

A construction weather report provides an important basis for decision-making in project planning, as it describes the likelihood of various weather conditions – such as wind, precipitation, and temperature – based on long time series of modeled climate data and local measurements. By combining our own model data with local measurements, the report offers a realistic picture of the climatic conditions at the site. 

Different projects may require different presentations of weather conditions, so feel free to contact us if you think this could be relevant for your project. Together, we’ll find a good solution for you and your project. Climatic conditions can be described in several ways, and here are some examples from previous projects to illustrate this. 

Wind

Here we have plotted a wind rose showing all wind speeds from our 45-year time series, and another wind rose showing only the top 1% strongest wind speeds. This way, you can see that the expected dominant wind directions in this area are from the northwest and east, while the strongest winds are most frequently expected from the south and northwest.

Precipitation

For precipitation, we can present expected monthly amounts divided into rain, wet snow, and dry snow. For the location shown in the example, total precipitation is highest in winter and autumn, consisting of various types of snow and rain, while in summer, all precipitation is in the form of rain.

We can generate maps of areas for various values – we’ve already created snow depth maps, extreme icing maps, wind maps, and as shown in the example to the right, precipitation maps.

Temperature

Temperature can be examined as air temperature, but also as wind chill, where wind speed and humidity are also considered. Here, wind chill is shown for each month for a given location, with minimum, maximum, and average values, as well as the distribution of values from the 45 years of modeled data. Effective temperatures below -25°C can cause frostbite within 10 to 30 minutes on exposed skin, while below -35°C can cause frostbite in just 5 to 10 minutes.

Weather Window

Sometimes it’s useful to look at combinations of different climatic factors – for example, when assessing how often fine tuned work with helicopters can be done during construction. In the example below, a weather window is defined – with maximum limits for wind speed, amount of rain and snow, absence of fog at relevant altitudes, and these conditions must persist for at least 5 consecutive hours. We’ve sorted the expected time with such weather windows for each of the four seasons over the 45 years of modeled data. Here, it is expected that there will be many more working hours within the defined weather window in summer than in winter, and the variation between years is greatest in winter and summer, and smallest in autumn and spring.

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Typical projects where we’ve created construction weather reports include projects for Statnett when planning power line construction, and for the Norwegian Public Roads Administration or county municipalities when planning bridge construction.

But construction weather reports are not limited to these – there are many other types of construction projects where knowledge of expected weather conditions is important! Together, we can find a good solution for you and your project.