Normal rain by month, heat, snow and median frost dates for one reference airport in each region, from NOAA’s 1991-2020 climate normals.
Source: NOAA NCEI U.S. Climate Normals 1991-2020 (monthly and annual/seasonal). Snow is shown only where the station’s normals include it. More on reading your climate in How to Draw a Landscape Plan for Your Yard, Step by Step.
How to read the check
Each region is represented by one long-running airport station in NOAA’s U.S. Climate Normals for 1991-2020. Normals are 30-year averages, so a single year can be much wetter, drier, hotter or colder. Your own yard can differ from the airport, especially with elevation, distance from the coast or a city’s warmth.
Months with less than 1 inch of normal rain are marked as watering months. That is a planning signal, not a rule: sandy soil, wind, heat and new plantings all raise the need for water, and established native plants may need none. EPA WaterSense suggests grouping plants by water need so each hydrozone can be watered on its own.
Frost dates are NOAA’s median dates for the last spring and first fall low of 32 degrees: in half of years the last frost comes later than the spring date. Where 32-degree nights are rare, as at the Miami, Phoenix and San Francisco airports, no dates are shown. For your zone and the plants it supports, see Find Your Hardiness Zone and What It Really Tells You.