I rode Sherman pass yesterday. The weather could not have been better.
Yep, sometimes there are nice dry days even in midwinter and some snowy days in the summer.
It's not so much the time of year (but it does change the odds!) at the higher elevations. The weather should always be checked. Sometimes in mid summer there can be violent thunder storms even if snow is not an issue.
So there is really no time of year where that going to Tahoe is too late (or too early). Just check the weather before leaving. Yeah, it sometimes makes planning a trip difficult.
Many years ago, I had a mountain cycle trip planned for Memorial Day, end of May. This was in the 1970's, before the internet. So I listened to my scanner and it clearly said "snow level 3,000 ft". I decided to go anyway and take my chances. Right at the 3,000' ft elevation sign, there was snow. The snow started less than ten feet after the sign. Since then, I have taken the weather reports a lot more serious.
There are really only two seasons at the high elevations. the end of one winter and the start of the next. With a few breaks in between.
-Don- Auburn, CA