Bug in weather_level_adj.py plugin

You could just use any variant of a safe float/int function for example:

def safe_float(s,d):

  try:

    return float(s)

  except:

    return d

Then just replace any instance of float in your script with safe_float(data, defaultfloat value)

I’ve found that checking data on weather underground more often than once every 15mins does little to add useful information for calculating watering schedule modifications. Even a single check just prior to a scheduled watering event is often enough, given returned data is valid and useful.
If weather data is used as a rain sensor of sorts, then simply factoring in forecast, and current co editions to that single check, will reduce accidental watering during rain events to a negligible level.
My suggestion would then be the definition of acceptable defaults for the correction of odd data loss and on demand requests for data used to adjust schedules, or display current/ forecast information. I highly doubt a computer of any sort cares what the weather was like 15mins ago if you yourself have no interest in using the information.
Outside of the meteorological fields high resolution historical weather information is geewiz at best in most cases. It’s good practice to constantly refine programs toward the average, and then handle the outliers.

I see what is happening now, except: is a catch all, if you would like to only extend the sleep when certain errors happen, use the applicable exception for example:

try:
  //some code you hope works
except (TypeError, ValueError):
  //increased sleep time
except:
  //something else happened leave sleep time alone and do whatever you do for errors 

A list of all exceptions can be found in the python documentation, if you simply want to ignore errors use except: pass
I think simply handling certain errors appropriately would do wonders for you and would be quite simple to implement. Python has a ton of code built in for handling problems, seems to be designed for writing code assuming everything will work, then just quickly deal with whatever goes wrong. Easier to ask forgiveness than permission, type programming.