Between commuting and recreational rides I ride ~330 days a year.
>>1211180IMO the cold is easier to beat than the heat. Layer up and you can commute well below 0f. The heat gives you a hard exertion limit.
Coldest I have commuted is -8F. Hottest was 96f with a heat index of 115f. Ideal commuting weather is dry with temps between 40f and 65f. Worst is 35f with rain. Snow and ice are fun to ride on.