I was wondering how far ahead the GFS pressure, temperature & rainfall
charts can be relied upon. The reason for the question is that we're
off on our Holidays to Switzerland in August and the Gfs charts seem to
be suggesting a much improved outlook which quite frankly i'm
desperately hoping is correct. I had read somewhere that the charts up
to +240 can be considered fairly accurate but become rather fanciful
after that.

If someone could advise me please that would be great.

Many thanks