diff --git a/cmd/derpprobe/derpprobe.go b/cmd/derpprobe/derpprobe.go
index 56e08ae64..3a295250b 100644
--- a/cmd/derpprobe/derpprobe.go
+++ b/cmd/derpprobe/derpprobe.go
@@ -23,13 +23,14 @@ var (
 	derpMapURL = flag.String("derp-map", "https://login.tailscale.com/derpmap/default", "URL to DERP map (https:// or file://)")
 	listen     = flag.String("listen", ":8030", "HTTP listen address")
 	probeOnce  = flag.Bool("once", false, "probe once and print results, then exit; ignores the listen flag")
+	spread     = flag.Bool("spread", true, "whether to spread probing over time")
 	interval   = flag.Duration("interval", 15*time.Second, "probe interval")
 )
 
 func main() {
 	flag.Parse()
 
-	p := prober.New().WithSpread(true).WithOnce(*probeOnce)
+	p := prober.New().WithSpread(*spread).WithOnce(*probeOnce)
 	dp, err := prober.DERP(p, *derpMapURL, *interval, *interval, *interval)
 	if err != nil {
 		log.Fatal(err)