Review of manuscript ‘Wine must yields as indicators of May to July climate in Europe, 1416–1988’ submitted to the journal Climate of the Past.

Authors of the manuscript: Christian Pfister, Stefan Brönnimann, Laurent Litzenburger, Peter Thejll, Andres Altwegg,Rudolf Brázdil, Andrea Kiss, Erich Landsteiner, Fredrik Charpientier Ljungqvist, Thomas Pliemon.

Dear Authors,

Please consider my comments below, which have been formulated to enhance the manuscript in a positive and constructive manner.

1. General Comments

The manuscript addresses relevant scientific questions within the scope of the journal Climate of the Past, presenting novel concepts, ideas and data. However, data analysis was only completed until 1988.

The abstract provides a concise and complete summary.

The scientific methods and assumptions are valid and clearly outlined. The results are sufficient to support the interpretations and conclusions. Substantial conclusions are reached, but the conclusion section of the manuscript could be improved.

The authors give proper credit to related work and clearly indicate their own new/original contribution.

The overall presentation is well structured and clear, and the language is fluent and precise.

The number and quality of references are appropriate (see exceptions in the specific comments section below).

No supplementary material provided.

1. Specific comments

Title: I suggest slightly changing the title to reflect the contents of the paper clearly: Wine must yields as indicators of May to July climate in Central Europe, 1416–1988’. Use Central Europe or a better designation for the study area in the title. The use of Europe in the title can be misleading, as many wine regions (e.g. Southern and Mediterranean Europe) are not included in the analysis.

Abstract - Line 17: “Narrative historical records of wine production in Central Europe date back to 1200.” This sentence requires a reference; therefore, it must be removed from the abstract and included elsewhere in the manuscript (e.g. Introduction). In addition, only data from 1416 is being used as a proxy.

It must be clearly stated why there is no analysis of data after 1988. What are the reasons? Data availability? It would be interesting to include the recent warmer decades in the analysis if data are available.

Make sure to add the references: Lines 39-40, 44, 57-58, 75-76, 536-537.

Use different references instead of Wikipedia: Lines 158, 495-496, 510.

Line 76: briefly specify the relevant results.

Section 3. Sources – It would be great to include a few figures of the original sources to highlight a few examples.

Section 5. Statistical methods. Please make sure to use a statistical textbook/peer-reviewed publications to add references to the used methodologies:  low order polynomial, ordinary least squares, orthogonal polynomials, Kolmogorov–Smirnoff test and detrending techniques. Adding references is important to ensure the description of experiments and calculations is sufficiently complete and precise to allow their reproduction by fellow scientists (traceability of results).

It would be great to cross-reference the results of the analysis of the historical data with references on future effects of climate change on wine grape production in terms of quantity, quality, and resilience of the wine regions included in the study area.

1. Technical corrections

Line 38: Europe, not Europa.

Line 40: table, not Table.

Line 265 (table): Luxembourg.

Moselle is written in the text, but it is spelt as Mosel in the graphs.

Figure 8: Decimal points must be used instead of commas in the Y axis.

I hope my comments are viewed as positively constructive and will assist the authors in enhancing their manuscript. I wish the authors well as they consider these comments and edit their manuscript for possible publication in the Climate of the Past.

(version en Français) L’utilisation de données proxy liées à la viticulture n’est pas nouvelle, comme les auteurs le détaillent de façon précise avec les références bibliographiques appropriées. De ce point de vue, l’intérêt majeur de ce travail est d’avoir fait appel à l’utilisation de différentes sources de données liées à la vigne, et dont l’analyse combinée a produit des résultats aussi pertinents que passionnants.

Je souhaite aussi souligner la pertinence géographique des sites d’étude. En effet, l’intégration des régions de l’Est de la France à une étude sur l’Europe centrale n’est pas systématique d’une publication à l’autre, alors qu’elle se justifie par la régionalisation climatique de l’Europe. Ce choix est donc d’un intérêt tout particulier dans l’article de C. Pfister et al.

(English version) The use of proxy data related to viticulture is not new, as the authors detail in a precise way with the appropriate bibliographical references. From this point of view, the major interest of this work is to used different sources of data related to the vine, and whose combined analysis has produced results as relevant as exciting.

I also wish to emphasize the geographical relevance of the study sites. Indeed, the integration of the regions of Eastern France into a study on central Europe is not systematic from one publication to another, even though it is justified by the climatic regionalization of Europe. This choice is therefore of particular interest in the article by C. Pfister et al.

Presentation quality: Regarding the quality of the writing in English, please ask confirmation from an English-speaking colleague (this is not my case).

Specific comments: Please enlarge figure 07, in order to improve its readability.