Recalibrated Weather Data Sets

Speedwell Recalibrated Datasets re-base historical temperature data for important reference sites by adjusting for known or observed discontinuities that have accumulated over the lifetime of the observations. Discontinuities may arise from instrumentation changes or changes in the location of the measuring instruments.

"Recalibrated data is the best possible baseline for risk analysis"


Why Recalibrated data is crucial:
  • Houston (KIAH): discontinuity in previous decade equivalent to > 200 HDD on a seasonal basis
  • Kansas (KMCI): repeated discontinuities in current decade equivalent to circa 100 HDD on a seasonal basis
  • Philadelphia (KPHL): discontinuity corresponding to > 200 HDD on a seasonal basis in previous decade
  • Dallas (KDFW): large warming and cooling discontinuities due to recent station changes

Impact of station moves on the KIAH historical record (minimum temperature)



What is a Discontinuity?

A discontinuity is a sudden, distinct, and continuous change in the long term observations for a site. A discontinuity represents an end of one continuous regime and the beginning of another. A discontinuity is not a trend. Temperature discontinuities can take the form of warmer or cooler temperatures and / or changes in the variance of the observations. Corrections for all aspects of the discontinuity are important
Discontinuity: a sudden, distinct, and lasting change


Recalibration Theory

Let's suppose that for every location (airport) you have an ideal station (no moves, changes,..) and a real-world station. By comparing the difference between the two time series you can detect discontinuities created by the real-world changes to the station.

Unfortunately, ideal stations do not really exist.

The solution is to create your own ideal station. This is accomplished by modeling an ideal station using data from surrounding stations. The modeled ideal station is known as the reference time series.

We are then able to statistically analyse the difference time series (DTS) for discontinuities. These results coupled with an understanding of the stations history (metadata) allows one to accurately detect and quantify discontinuities.

Who should use Speedwell Recalibrated Datasets?

Weather Derivatives Traders - critical for pricing of weather risk contracts where such adjustments are financially material in the modelling of current behaviour of a weather reference site.

Energy Demand Modellers- important for demand modelling and those seeking a precise understanding of current "climatology" at a given site.

Meteorologists / Climatologists - recalibrated data serves as an accurate baseline for comparison when forecasting or making comparisons against "normal"



Speedwell Recalibrated Datasets (What is included?)

The Speedwell Recalibrated Datasets bring an unprecedented level of sophistication to the process of recalibration combined with transparency of method and a unique real-time web-based service for monitoring the on-going behaviour of the reference site.

Speedwell Recalibrated Datasets are provided on a subscription basis and are available for individual sites or packs. Subscribers receive access to the Recalibrated Dataset pack, the Monthly Report, Airport Maps, and the Real-Time Web Monitor.

Recalibrated Datasets Pack

Delivered on initial subscription and then updated on a six-month cycle the pack comprises:
  • Raw meteorological observation dataset as provided by the relevant National Met Service.
  • Cleaned dataset [erroneous observations replaced and missing values filled]
  • Speedwell Recalibrated Dataset [cleaned data that has been adjusted to remove discontinuities]
  • Recalibrated data supporting documentation:
    • Station overview with commentary.
    • Information regarding the proxy stations used and the creation of the synthetic time series.
    • Graphical representation of the statistical analysis.
    • Station metadata - the most comprehensive archive available (includes an airport change analysis diagram).
    • Discontinuity table with comments.
    • Valuation impact on monthly HDD and CDD values of the Speedwell Recalibrated Dataset compared with the cleaned dataset.

Monthly Report

Monthly report detailing changes in recent station behaviour with meteorological commentary, metadata updates, and the notification of future station changes.

Airport Maps

For US CME sites, the Speedwell Recalibrated Datasets subscription provides access to an on-line archive of annotated airport maps in one-year time steps. This helps the user to understand how recent site developments may impact on behaviour.

Real-Time Web Monitor

Subscribers to the Speedwell Recalibrated Dataset are provided with access to web-delivered software that allows the user to see the latest performance of the primary site against a synthetic basket of near-by sites. The user is able to plot moving averages and difference series for different periods to view recent trends. Key statistics are summarised in an easy-to-read sortable table for all subscribed sites. This is updated daily showing any significant recent moves.


For more information and subscriptions please contact:

Phil Hayes (U.K.) U.K. Office +44 (0)1582 465 551
or David Whitehead (U.S.) U.S. Office +1 (0)703 535 8801


Or please contact us via the contacts page.