This article will be of interest to those working with CFFDRS components. The article content supports the data set publication. The data set is useful and of high quality. The data set publication, as submitted, is of high quality. My recommendation is publication with minor revision to the manuscript. Specific comments follow:

Line 104: Perhaps add a reference to the validation of ERA5 or say something about the confidence of using the dataset. It makes sense to use this dataset for the purpose presented here, but are there modeling issues especially with hourly precipitation that could affect the study results? In other words, what is the confidence in using this dataset and perhaps why was it chosen versus other potential datasets. In the discussion section you do make a reference to extreme-value biases in ERA5.

Line 239: Do you think that there were any issues for this direct grid point comparison in complex terrain?

Line 258: 02:00AM is a local time for which time zone?

Line 375: Do you have a sense of how different these records would look without the SN methodology?

Can you say something a bit more specific regarding management implications of the SN improvement?

Overall Assessment

The authors present a new method for computing the CFFWIS that leverages sun elevation data to increase the accuracy and representativeness of the computations. The topic is of high interest to the wildland fire community and may have potentially significant implications for fire management across Europe, especially considering the widespread use of the CFFWIS as a tool for assessing fire danger. The manuscript is very well written, following a logical structure that is easy to follow. 

Recommendation

I recommend accepting the manuscript for publication subject to minor revisions based on the comments that follow. 

Comments

L67: The authors' claim about creating a fine-scale dataset is a bold one, particularly when considering the spatial resolution of the final dataset (~31 km). I suggest removing the "find-scale" characterization; the authors could perhaps replace it with the term "novel".

Considering the arguments made by the authors in articulating their motivation, as well as the comparison and validation results presented, I believe it would be very interesting to to expand the analysis and discussion beyond the absolute FWI values. While those are certainly useful and the results indicate the added value of the approach proposed, the greatest interest lies in evaluating the impact of the SN approach on threshold- and percentile-based FWI values. For instance, I could argue that an enhancement of the accuracy in computed FWI by 2 units does not have much meaning if the resulting FWI corresponds to the same level of fire danger. On the other hand, if the refined FWI computation methodology yields a different "picture" when it comes to danger days or extreme days, then the added value for operational fire management would be larger, and should be highlighted.