The Wi-Fi only works when it's raining

Original Article ↗ Hacker News Discussion ↗

Context and “April Cools” framing

  • Thread notes this is part of an “April Cools” series: essays on unusual but supposedly real topics, published on April 1 but not meant as jokes.
  • Some commenters accept it as a true-but-odd debugging tale; others think parts could be embellished or apocryphal.

RF behavior: rain, trees, Fresnel zones, MIMO

  • Several comments explain that long-distance Wi‑Fi links are highly sensitive to line‑of‑sight and the Fresnel zone; objects not on the direct line can still interfere.
  • Trees, especially with leaves full of water, can significantly attenuate or distort Wi‑Fi, and rain can change branch position (sagging) and water content.
  • Others mention that humidity, fog, snow, and wet ground can change propagation for RF, audio, and even copper phone lines.
  • One subthread clarifies that 802.11n’s gains come from MIMO; beamforming is one special case, and rich multipath environments can actually increase capacity.

Analogous “weird cause” outage stories

  • Many share similar “magical” failures:
    • Point‑to‑point links broken by cranes, ferries, trees, fog, schoolkids saturating 3G, or building lights/solar inverters emitting RF noise.
    • Microwave ovens, gas‑lift office chairs, static, USB 3.0, and Bluetooth/Wi‑Fi coexistence causing intermittent failures.
    • Toilets, pumps, hoists, and generators causing brownouts or EMI that reboot or crash systems.
    • Optical sensors and smoke detectors fooled by direct sunlight.
    • Cables or DSL/fiber joints that fail only in rain, cold, or at the first minutes of a storm.

Debugging lessons and culture

  • Commenters connect this to the “500-mile email” and “magic switch” genre: stories where physical reality contradicts simple software‑only mental models.
  • Several stress systematic debugging: verify each hop, check physical paths and logs, be wary of hidden assumptions (e.g., weird LOS links, bad cables, IPv6 packet bloat).
  • Others note how hard hardware and RF debugging is compared to software: each test is slow and sometimes invasive.

Skepticism and criticism

  • Some argue the story feels contrived: given a known line‑of‑sight Wi‑Fi bridge, obstructions should have been the first suspect.
  • A few doubt that a tree and light rain could have such a binary effect, or criticize burying the LOS detail mid‑article and overplaying the “magical thinking” tone.