The Wi-Fi only works when it's raining
A widely upvoted anecdote describes a home internet connection that only worked in the rain, ultimately traced to a long-distance Wi‑Fi bridge whose line of sight was intermittently blocked by a tree that sagged out of the path when wet. Commenters use the story to explore radio propagation concepts like Fresnel zones, interference in unlicensed 2.4 GHz bands, and the role of newer Wi‑Fi standards (MIMO, beamforming) in coping with imperfect conditions. The thread broadens into a collection of “impossible” debugging tales where physical-world quirks—from cranes and ferries to chairs, microwaves, and fog—produce counterintuitive network and hardware failures.
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.