Methanol-water mix freezing points - clarify contradictory online data > 60% w/w?

Question

Extending an exploration of windshield washer-fluid choices to freezing points of methanol-water mixes, all web-sources located agreed to within a couple of degrees from 0-60% w/w, yet above this proportion (and below 100%), repeatedly came across conflicting data (which fell into three groups). (Yes, the disagreements are all outside the range of winter driving on this planet - except perhaps for around Vostok Station...)

w/w	various graphs by eye	various tables	engineering toolbox table	all˚C
60%	- 71	- 71	- 71	˚C
70%	-102	-137	- 82	˚C
80%	-116	-143	- 87	˚C
90%	-108	-146	- 90	˚C
100%	- 96	- 98	- 98	˚C

examples of sources for above data:

http://www.methanol.org/wp-content/uploads/2016/06/FreezingPointsMethanol-WaterSolutions.pdf graph
https://patents.google.com/patent/WO2011153147A1/en table (~ 1/3 way into the document) https://www.engineeringtoolbox.com/methanol-water-d_987.html table

Thanks for any comment.

Answer 1

From Solid-Liquid Phase Diagram of the System Methanol-Water by G. A. Miller and D. K. Carpenter in J. Chem. Eng. Data 1964, 9, 3, 371–373 (July 1, 1964) [https://doi.org/10.1021/je60022a017]

"A solution of methanol and water that is methanol-rich tends to form a glass when cooled below the melting point. The liquid is very viscous at such temperatures (below -100° C.) because of the presence of hydrogen-bonded polymers. Because it is difficult to induce crystallization, the melting point is determined from a warming curve. Much of the wide divergence of melting point data for the composition range of 55 to 95 mole per cent* methanol results from the use of cooling curves."

* by a back-of-a-napkin calculation (assuming 32.042 g/mol MeOH and 18.015 g/mol H2O) the mole percentage mentioned is approximately 68% to 97% methanol (w/w).

Further - successful - online research was inspired by a comment; it appears the failure to find information with common search terms was due to a language difference. It seems specialists (presumably physical chemists) use "solid-liquid equilibrium" or "solid-liquid phase diagram" in documents which may completely exclude the term "freezing-point" - such as the publication quoted above which answers the original question.