To ascertain whether it is safe to fly I use a number of different weather forecasts, airfield METAR's and an anemoneter which I purchased over 5 years ago. Understanding wind speed is important as drones have operational limits and if you have a PfCO that will also set out maximum wind speeds. Flying and damaging a drone in speeds higher than those permitted could render any insurance invalid.
The problem is that winds pretty much vary all the time, forecasts are not always accurate and local coditions can be quite different to what you anticipated. I have sailed for over 30 years so you get a feel for wind speed but my old anemometer was at best a guide. I have however become increasingly concerned that it was simply far too inaccurate. You get what you pay for, it was at the cheaper end.
A quick internet search and I found ATP Instruments. I called them yesterday for advice and ordered the MT-915 which arrived today. I have just unpacked it and look forward to using it. I am confident it will provide more reliable information than my previous one. A quick test indicated a wind speed which matched the forecasts, the old one indicated wind speeds much lower.