In response to point (1):

We would like to thank the reviewer for suggesting an alternative way to summarise and present our results. In generating our Figure 1, we have considered previously several options and now have also followed up on the reviewers suggestion. 

Using curves instead of bars as suggested gives the impression that the onset dates are related from one season to the next. However, this requires the reader to know and understand that each onset date is a single point each year that is unrelated to the previous year’s onset. We would argue that our 'bar' type presentation avoids this possible misinterpretation by the reader. 

In regards to grouping the indices, this grouping was considered in Lisonbee et al. (2020). Thus in doing so again here would reproduce what has been done previously leading to a similar presentation, albeit showing different data. We would argue that our presentation in addition to the description provided in our paper is appropriate in conveying the key information from our analysis. 

In summary, we have retained our original  presentation  of the results (i.e. figure 1) since there appears to be no advantage in following up on the reviewer's suggestion. However, we would  like to thank the reviewer for prompting us to check our presentation again.

In response to point (2):

Yes, thank you for these comments. We modified Figure 2 and have now included a standard deviation bar around the mean. 

In response to point (3):

Many thanks for this suggestion. We have followed up on this and added a paragraph:

"To roughly test these explanations, we split the data into two periods of 36 years each. A bootstrapping technique was applied to both periods and changes in the data between the two periods were analysed. The mean onset date and STD changed by less than a day between each period. The SOI differs by only 0.4 between the two periods and it is concluded that these changes are small compared to the changes seen in the correlation between the two datasets."

Thank you for these thoughtful comments. You provided three points for us to address and we will provide a response to all three points in order.

In response the first point:

Thank you very much for this suggestion. We've added a small statement to our paper. 

Nicholls et al (1982) showed that 30% of the wet season rainfall occurs before the monsoon onset and 70% occurs afterword. At Darwin Airport the average rainfall total on days with > 0.2 mm of rain for non-monsoon days is 14.7 mm while the average daily rainfall amount for monsoon days is 21.3 mm. Pre-monsoonal rainfall is characterized by meso-scale thunderstorms, which may produce large rainfall totals locally on individual days, while monsoonal rainfall can produce large rainfall totals for multiple days and over a very broad areas (Pope et al. 2009). The impacts of wet season rainfall may appear in the early wet season, but the likelihood increases under a persistent monsoon pattern.

It is known that early wet season (Oct-Dec) rainfall correlates well with ENSO (McBride and Nicholls, 1983), thus this paper focuses on the dynamical monsoon.

In response to the second point:

Thank you, this is a really good point. Why should seasonal scale variability influence sub-seasonal scale weather patterns (i.e. the monsoon)? We are investigating this possibility because it has been proposed in previous research (Hendon et al. 1989; Drosdowsky and Wheeler, 2014; Kim et al., 2006; Kullgren and Kim, 2006; Nicholls, 1984; Nicholls et al., 1982; Smith et al., 2008; Webster et al., 1998) and we would like to test these possible connections in the most complete way possible. 

The reviewer is correct that the value comes in allowing for planning at longer time scales. At the moment, our best technology for predicting monsoon bursts is the MJO which provides predictability at multi-week timescales. If there was a connection between monsoon onset and seasonal climate drivers it would provide a valuable planning mechanism for agriculture producers and so many others in tropical Australia.

We have re-written the paragraph in question. It now reads:

"The MJO provides predictability of the monsoon onset at multi-week timescales. If there was a connection between monsoon onset and climate drivers on a seasonal (multi-month) time scale it could provide a valuable planning mechanism for agriculture producers and so many others in tropical Australia. This paper presents a statistical analysis of seasonal-scale(1–6 month) climate influences on the timing of the dynamical onset of the Australian monsoon for the period 1950-51 to 2020-21. With the acknowledgement that monsoon onset occurs on a sub-seasonal time scale, we are investigating this possibility because it has been proposed in previous research (Drosdowsky, 1996; Hendon et al., 1989; Kim et al., 2006; Kullgren and Kim, 2006; Nicholls, 1984; Smith et al., 2008; Webster et al., 1998) and we would like to test these possible connections."

In response to the third point:

Many thanks for this information. We followed up on this and included Berry & Reeder (2016) in our paper.