Our percentage based and fully customizable motorcycle weather forecast compares five user-configured variables. The worst of the calculated results gets posted to an overall quality meter with a complete list of secondary factors in tow. If you're not logged in, our default variables are in play. Said defaults target the average rider, so your own preferences might not be accurately expressed. These variables and their respective equations are as follows ...
1) Temperature
Temperature's Influence = ( ( Today's Predicted High Temperature - ( Temperature Base = Your Minimum Acceptable Temperature - ( Today's Predicted High Temperature - Your Minimum Acceptable Temperature ) ) ) / ( Your Ideal Temperature - Temperature Base ) ) * 100
Measured in fahrenheit, our defaults assume that your minimum pleasurable riding temperature is 50 degrees and that your ideal temperature is 73. Should temperature be the most influential factor, i.e. no other factors are worse than temperature, that minimum figure of 50 degrees (or whatever you set it to) falls directly on our quality meter's 50% mark, representing your "take it or leave it" threshold. Anything above 73 degrees tops out at 100% or "perfect" conditions but once the thermometer hits 80+ (again, this and everything else can be customized), the day's riding schedule is split into two sets of opportune hours in the late morning and early evening.
2) Precipitation
If Chance of Precipitation > Your Alert Setting, Precipitation's Influence = Chance of Precipitation
By default (and assuming again that there are no other problematic factors of greater value), any chance of precipitation will effect the quality meter. The point at which precipitation is allowed to influence the meter, however, can be changed much like anything else. If you don't see a 15% chance of rain as a realistic threat, set your preference above "15" and you won't be notified unless the possibility surpasses it.
3) Wind Speed
Wind's Influence = ( ( Low, High and Gust Wind Speeds Averaged - Your Minimum Setting For "Windy" ) / ( Your Minimum Setting For "Hazardous" - Your Minimum Setting For "Windy" ) ) * 100
Mainstream meteorology suggests that "windy" conditions are anything sustained above 15 miles per hour, so that's where we've set the bar. Jokingly, once our helmets begin inflicting a concussion (25-30 MPH wind speeds), the term "windy" translates to what our defaults deem hazardous. Again, you can adjust to suit, though you might be better off hang gliding.
4) Visibility
If User-Activated and Total Visibility < Two Miles, Visibility's Influence = ( ( Miles / 10 ) * 100 )
This doesn't really become problematic until the total distance drops below the two mile mark. Even then, many dirt riders will continue on. For this reason, we've kept things simple. If visibility lands at two miles or less, only then does it get compared against the other factors. Moreover, it can be enabled/disabled per your preference.
5) Road Conditions
Here we have the wildcard which, like the visibility variable, can be enabled/disabled accordingly. The influence of our road conditions algorithm is strengthened or weakened depending on it's array of mathematic operators. If the high temperature is below a day's minimum dew point, this factor's influence is calculated before being scaled down to 1/4 it's initial value, allowing only 25% of the total 100% weather quality to be effected by the result. When using the high temperature and average dew point, that 25% drops to 12.5% and even lower (6.25%) when the only figures we have to go on are a day's average temperature and average dew point.
It's loose math (hence the governed output) but we build on this "useful inaccuracy" by combining the alternative approach that is word analysis. That's right. There's more ...
Along with the "soft" dew point calculations above, there's the matter of National Weather Service hazard reports. We subtract ten percent from the overall quality for every bullet word in said report. Such words include "icing", "road", "commute", "motorist", "travel" and others. When their total is compounded with the dew point and temperature data, we get a graceful but not overly influential hint about prospective road conditions.
... And That's About It!
As usual, we built this system for our own personal use before dredging our way through the code for customized member settings. It's development continues for improved accuracy and usefulness and with that, your critiques and bug reports are openly invited. Visit the contact page should you have any concerns or innovations which might better our motorcycle weather forecast!