This question of "what is the best time of year to drive route 66" gets asked a lot, but there's no simple answer. A member of the Facebook group recently came out with this little gem: "anytime between January and December"!
However, as correct as that answer is, it doesn't help you make a decision with regards to your trip planning. The reason the question is not as easy as you might think is because different people have different expectations and personal preferences. The first step in working out what the best time of year is to consider what you hope to get out of the trip. Here are some factors to consider...
When you're driving over 2400 miles through varied terrain you can't exactly predict the weather with accuracy but it's fair to say that the best (driest or warmest) weather will be between April and October.
During the winter months - December to February - the temperatures can plummet to -40°F (-40°C) and the winds can chill you to the bone. The deserts of Arizona can be equally cold overnight and snow can fall in the unlikeliest of places. Icy roads, sleet and snow will impact on driving conditions and isn't for the faint hearted. It's also worth keeping in mind that road closures due to extreme weather can delay your travel, and the shorter days will limit your time for sightseeing.
November and March are the months transitioning in and out of winter and so weather, although milder than during winter, can still be unpredictable. It's not unheard of for there to still be snow in March. The tourist season is off-peak and so the roads will be quieter but you run the risk of businesses being closed as a result (more on this later).
The weather improves between the months of April and October, peaking during July and August. The weather is fair during April, May, September and October, and the crowds are less abundant. May and September are considered good months to travel route 66 if you're not a fan of the intense heat that comes with the summer months. You get the benefits of fair weather and reduced tourism.
June, July and August are the peak months in terms of both tourism and temperature. The temperature regularly exceeds 105°F and can be intense if you're not used to it. Although the western states have a dry heat, the eastern states of Missouri and Illinois can be quite muggy. Days are also longer with bright mornings and mild evenings. I traveled during these months and thoroughly enjoyed it - being from the UK I found it a welcome treat! If you're someone that finds intense heat overbearing or oppressive then you might want to avoid July and August in particular. However, if you're a sun worshiper you'll be in your element! A summertime route 66 trip is fantastic, but consider how you'd feel in such sweltering heat.
Don't forget, when renting a vehicle you'll be guaranteed to have air-conditioning to keep you comfortable. It's also worth keeping mind that July and August is the monsoon season in New Mexico, Arizona, and California, while the risk of seeing a tornado is increased in the midwest.
Between October and April many of the businesses and attractions along route 66 close down due to lack of tourists. Others will remain open but will operate on reduced hours or weekends only. Although this is an obvious drawback one plus point is that there can be lower prices and better discounts.
From May onwards route 66 tourism will steadily increase before peaking during the summer and tailing off in September. Many people choose the months of May and September for their road trip for just this reason - the crowds will be smaller and the roads will be quieter. From early September the crowds drop off quickly and there are less people on the road as schools start back and people return to work following their summer vacations.
As with many countries around the world July and August are the major school breaks and vacation periods in the United States. The summer months (June to August) are the peak season for route 66 tourism so expect the roads to be busier, rates to be higher and queues to be longer. Don't picture interstate-level of traffic though, you will still have sections of quiet roads, it's just that during the summer you are more likely to encounter other travelers - plenty of people to swap stories and tips with. A road trip in the summer is an amazing experience, just expect to see more like-minded roadies.
Once you've considered all of the above the final point to consider is when can you actually travel. We all have commitments and few of us have the complete freedom to take a long road trip anytime we want.
The truth of the matter is that whenever you go you're going to have a fantastic experience!