67:
We had at one time traveled with a sophisticated weather station, however today, we have to a great extent replaced it with our Android cell phones & simple barometric pressure device & hand-held anemometer (we have several tools installed on our Androids that give us direct connection to Doppler radar, and mesoscale visualization, and weather satellite product).
We research & know the following to determine what kind of device would be pin-point effective for us to avoid injury or death due to anomalous climate events: 
-what genre of life-threatening weather, and the geophysical landscape that could channel such weather to our locale.
A simplistic example of weather genre is: Kansas = tornado; East Coast shoreline = storm surge/hurricane; Southwest = flash flood; Southwest = killer wildfires; Pacific coastline = killer tsunamis. There are hundreds of variations in climatological genre (climate overlap) that are possible.
A simplistic example of geophysical landscape that could channel an anomalous climate event to your camper's doorstep are: setting up in a dry wash (knowingly or unknowingly); camping 1, 2, 3 meters above the mean high tide line along the Atlantic/Pacific; camping between two dry arroyos boxing you in; camping on ocean shoreline with only 1 or 2 escape routes; camping in a dry area conducive to wildfire with abundant fuel barriers to escape route(s); etc. Again, there are MANY variants to these geophysical scenarios, and several tools that could save our lives (eg. having an hand-held anemometer in fire country).
If we were putting ourselves in the Southwest, I would carry either/or a lightening detector (good for 20+ miles) and Doppler Android cell application on 2 phones (and, a GPS coverage map of cell tower effective range). And, I would have a LiDAR terrain model (and watershed coverage) to select a secure campsite.
If we were putting ourselves on the East Coast during hurricane season, we would carry a NOAA weather alert receiver (battery operated), a cell with backup with various satellite link Android apps, and a barometric pressure sensitive device. And, I would have a LiDAR coastal terrain model (and watershed coverage & storm surge GIS software with coastal zone loaded & emergency services escape routes loaded into my GPS & cell phones) to determine where/where not to camp, and how to escape.
If we were putting ourselves in Kansas/Midwest during spring/summer, we would carry a cell and backup, with mesoscale meteorological  Doppler application, and NOAA weather receiver. And, an escape route from every night stop going in every direction, and a concrete bunker at every night stop to take shelter in if need be.
....etc, etc.
On edit: feel free to cherry-pick :B
Good luck,
S-