raw · papers · ingested 2026-07-19
Evaluating Heat Index and Winter Weather Criteria in Deep South Texas and the Lower Rio Grande Valley
Source: https://www.weather.gov/media/bro/research/pdf/heat_cold_weather_NWARydell09.pdf
Authors: Nezette Rydell, Jeral Estupinan, Barry Goldsmith — NWS Weather Forecast Office, Brownsville, TX. National Weather Association paper, 2009 (criteria established 2008; report covers data through summer 2009. Exact publication day not confirmed).
Summer heat data (McAllen, 1997–2004)
Heat index ≥108°F on two-thirds of summer days; ≥110°F on one-third; ≥111°F on ~6 days/summer. The local NWS heat-advisory criterion is HI ≥111°F sustained 2+ hours on 2 consecutive days — a very high bar, reflecting how routinely extreme baseline heat is in this region. Summer max-temperature variance is remarkably low (standard deviation ≤5°F, June–August) — oppressive heat is the norm for the entire summer, not an anomaly. 17 heat-related fatalities were recorded 1997–2006 (likely an undercount); roughly 15% of Rio Grande Valley households have no air conditioning or heat at all.
Winter data
Freezes are rare — only about 5 significant winter events in over a century (1899, 1951, 1962, 1983, 1989) — confirming that heating is a minor design concern in this region.
Why it matters for this archive
The essential regional-climatology grounding for any South Texas passive-thermal build: heating is nearly a non-issue, while summer cooling load is severe and sustained (not an occasional spike). Directly informs the safety framing of a South Texas cat-shelter experiment. See Night-sky radiative cooling § Climate dependency.