Duluth Water Temperature by Season: What the 2021–2025 Station Record Shows
A qualified analysis of NOAA's Duluth station record: May–November temperatures, an August peak, autumn heat retention and explicit winter data gaps.
FIELD NOTES & DATA EXPLAINERS
A closer look at
water temperature.
Local seasonal patterns. Regional differences. The science behind the reading.
10 researched articles with primary sources, transparent methods and links to local conditions.
STATIONS & SEASONS
Local research
Key West water temperature by month: a station-based seasonal analysis
Monthly Key West water temperatures from qualified NOAA station records, with historical ranges, exact year coverage and an explicit January data gap.
La Jolla water temperature by month: what five years of observations show
An original analysis of 2021–2025 NOAA observations at La Jolla, with monthly averages, 10th–90th percentile ranges, coverage counts and clear limits.
San Diego Bay vs. La Jolla: a five-year water-temperature comparison
Compare monthly NOAA station averages for San Diego Bay and La Jolla in 2021–2025, with the seasonal differences and limits of an unpaired comparison.
COASTS & LAKES
Regional research
Great Lakes Water Temperature: Why the Shore and the Lakewide Average Differ
How to compare a Great Lakes station reading with NOAA's GLSEA surface analysis, and why depth, wind and seasonal heat storage create real differences.
Why Outer Banks Water Can Turn Cold During Warm Weather
Research from the North Carolina shelf explains wind-driven upwelling, seasonal differences and why the Gulf Stream does not set every beach temperature.
Why San Francisco's ocean water stays cold: currents, upwelling and the bay boundary
A research-based explanation of cold water off San Francisco, the seasonal role of coastal upwelling, and why a bay thermometer cannot stand in for Ocean Beach.
UNDERSTANDING THE MEASUREMENT
National research
Does an Unusually Warm Reading Mean a Marine Heatwave?
Why a water temperature above the usual monthly range is different from a marine heatwave, and how duration, baseline, and location change the answer.
Why Satellite and Buoy Water Temperatures Can Disagree
Understand NASA MUR sea-surface analysis, buoy sensor depth, observation timing, and the approximate temperatures produced by clicking our map.
Why a Hot Day Can Still Mean Cold Water
How heat storage, sunlight, evaporation, mixing, currents, and sensor depth explain why water temperatures do not follow the air forecast.