Of course, the idea of an objective best or perfect day is a little tongue-in-cheek—but it’s fun to consider.
We defined a “perfect” weather day as:
• 🌡️ High temperature in the thermal comfort “Goldilocks zone” (68–82 °F)
• 🌡️ Low temperature that keeps nights comfortable (50–65 °F)
• 💧 Dew point to avoid muggy stickiness or desert dryness (40–60 °F)
• 🌬️ Wind speed capped below 10 mph for pleasant outdoor conditions
• ☁️ Cloud cover allowing sun but avoiding oppressive gray skies (0–65%)
Using 30 years of high-resolution (4 km) dynamically downscaled ERA5 weather reanalysis data, we counted how often each U.S. ZIP code meets the criteria (Contiguous U.S. only).
☀️ The results aren’t surprising: the Mediterranean climate along California’s coast delivers the most perfect-weather days. In some spots, almost a third of the year is classified as “perfect”.
🏡 Coastal California pairs abundant “Perfect Weather” days with sky-high real estate prices in places like LA. But other locations, like New York City, remain among the most expensive in the country, despite offering far fewer days of ideal weather.
📊 Want to see how your ZIP code stacks up?
We’ve made the “Perfect Weather” days by ZIP code dataset freely available for download. Check it out and find how many perfect weather days your ZIP code has each year.
💭 Does it match your expectation? What’s your idea of a perfect weather day?
❄️ About Degree Day
Degree Day is a small physical climate risk business founded by scientists to provide high-quality, bespoke, and transparent views of climate and extreme weather risk. Our expertise is supported by nearly 15 years of published academic research on climate risk. If you are stuck trying to interpret data or need help with finding ways to use data to save your business money and improve resilience, we are here to help. Reach out and let us know what you are struggling with.
