What can we learn from weather apps user complaints?

<p>Meteored’s goal is to provide a weather forecast to an heterogeneous audience around the world through its websites and mobile apps.  Although the meteorological information is available through several products such as radar, satellite or weather field maps, most of the views are focused on checking the forecast for a specific location. Our weather forecast is built on the HRES model from ECWMF, which is post processed, spatially interpolated to the interested coordinates,  and, finally, summarized in several weather symbols. If any user doesn’t agree with the symbol that represents the forecast, she/he can select which symbol better represents its weather perception.</p><p>Using this simplification to validate forecast entails several challenges: 1) Spatial representativeness; there aren’t weather stations at each location where users demand to validate, 2) timing; sometimes there is lack of concurrency between a weather phenomenon and the user weather check,  3) user perception; same symbol can represent different weather for different users, and 4)  population density; most of the user complaints are focused on the most populated regions but this doesn't mean the performance is worse there.</p><p>Last year more than 374000 symbol suggestions were recorded from worldwide users, mainly from Europe and Southamerica. The percentage of complaints were 39% cloudy, 24% rainy, 21% suny, 8% storm, 5% snow and 3 % foggy. 16 % of the complaints happen when a cloudy symbol is shown but the user suggests a rainy symbol. Temporal series show more feedback during summer and slightly lower during March (maybe due to the pandemic). Complaints about snow significantly increased due to the historical event in Spain during January. From weather feedback, the straightforward question is: why most frequent complaining is about cloudiness? We can find several answers: there is an important error in the weather modelling, there is an error in the symbol representation, it is a frequent meteorology event or it is one of the most relevant in users daily life.</p><p>In order to understand how reliable the user’s feedback is, our forecast is compared against almost 10000 SYNOP observations, assessing 2 m temperature, 10 m wind speed, precipitation, fog and also, symbols. Preliminary results show a pronounced dependence of the bias with the orography with larger errors over some islands and over main mountain systems. This spatial variability for bias is smoothed in Meteored forecast due to biquadratic interpolation. However, the Meteored forecast has a diurnal cycle bias error with higher temperatures during the daytime and lower temperature at nighttime due to the temporal interpolation approach.  Regarding to the weather symbols validation is difficult to extract conclusion since failures and hits are hetereogenously distributed. In addition,  most discrepancies are related to fog although it has a low percentage of complaints. </p>

Migraine and weather: A prospective diary-based analysis

Aims Weather is mentioned as a trigger factor by migraine patients most frequently. We examined the impact of meteorological factors and the impact of their day-to-day change on the risk of occurrence and persistence of headache and migraine and the correlation of subjective weather perception with objective weather data. Methods We performed a prospective, diary-based cohort study in 238 patients suffering from migraine with or without aura. Patients had to live within 25 km of the Vienna meteorological station and were required to keep a diary for 90 days. We analysed 11 meteorological parameters and 17 synoptic weather situations. For evaluating the hazard of occurrence and persistence of migraine and headache, we performed a univariate and a stepwise multivariate Cox regression analysis. We calculated correlations between subjective weather perception and meteorological data. Results In the uni- and multivariate analysis, a ridge of high pressure increased the risk of headache occurrence, lower mean daily wind speed increased the risk of migraine occurrence and a day-to-day change of daily sunshine duration increased the risk of migraine occurrence. A day-to-day change of the daily minimum temperature decreased the risk of migraine persistence. After correction for multiple testing, none of these findings remained statistically significant. Subjective weather perceptions did not correlate with the occurrence or persistence of migraine or headache. Subjective perception of cold and too-cold weather and of too-warm weather correlated with daily minimum, mean and maximum temperature. Conclusion The influence of weather factors on migraine and headache is small and questionable.