Phoenix is 15.1°C (27.2°F) warmer by day, Phoenix has 8.2°C (14.8°F) warmer nights, Seattle gets 961 mm (37.8 in) more rain a year.
Phoenix is at its warmest in July and coolest in January, while Seattle peaks in August and bottoms out in December. Month for month, Phoenix is the warmer of the two in 12 of 12 months.
Seattle is the wetter of the two, collecting 1,255 mm (49.4 in) of rain a year against 294 mm (11.6 in) in Phoenix. The most comfortable time to visit is April, October and November in Phoenix and July, August and September in Seattle.
| Phoenix | Metric | Seattle |
|---|---|---|
| 🌡️ Temperature | ||
| 85.6°F | 🌡️Average daytime high | 58.5°F |
| 58.6°F | 🌙Average nighttime low | 43.9°F |
| July | 🔥Hottest month | August |
| January | ❄️Coldest month | December |
| 🌧️ Rain | ||
| 11.6 in | 🌧️Annual rainfall | 49.4 in |
| August | ☔Wettest month | November |
| June | 🏜️Driest month | July |
| 💨 Climate | ||
| 35% | 💧Average humidity | 83% |
| 2 m/s | 💨Average wind speed | 0.7 m/s |
Overnight, Phoenix typically falls to around 14.8°C (58.6°F) while Seattle settles near 6.6°C (43.9°F).
Phoenix is hottest in July and coldest in January, whereas Seattle peaks in August and is coolest in December.
Phoenix sees the most rain in August and the least in June; Seattle is wettest in November and driest in July.
Seattle feels the more humid of the two, averaging 83% relative humidity against 35%.
For Seattle, the pick of the year is July, August and September.
Month by month, here is the coldest night, the average day and the hottest afternoon each city can expect. Switch Compare to read rainfall, humidity, wind or solar instead, and Period to move between the long-term 45-year average and any single year — the shading is a quick warm-to-cool guide.
| Month | Phoenix | Seattle | ||||
|---|---|---|---|---|---|---|
| Min | Avg | Max | Min | Avg | Max | |
| January | 41 | 53.6❄️ | 66.2 | 35.1 | 40.1 | 45 |
| February | 43.2 | 56.1 | 69.3 | 34.9 | 41 | 47.1 |
| March | 47.3 | 61.5 | 75.6 | 37.8 | 44.8 | 51.6 |
| April | 53.4 | 68.7 | 84 | 40.8 | 48.6 | 56.5 |
| May | 62.4 | 77.9 | 93.4 | 46.2 | 54.7 | 63 |
| June | 72.7 | 88.3 | 104.2 | 50.7 | 59.2 | 67.6 |
| July | 79.7 | 92.3🔥 | 105.1 | 55 | 64.2 | 73.2 |
| August | 79 | 91 | 103.1 | 55.8 | 64.9🔥 | 74.3 |
| September | 72.7 | 85.8 | 98.8 | 51.4 | 60.4 | 69.4 |
| October | 60.8 | 74.3 | 87.8 | 45 | 52.2 | 59.5 |
| November | 49.5 | 62.4 | 75.4 | 38.8 | 44.2 | 49.6 |
| December | 41.5 | 53.8 | 65.8 | 34.3 | 39❄️ | 43.7 |
| Annual Avg | 58.6 | 72.1 | 85.6 | 43.9 | 51.1 | 58.5 |
Min / mean / max temperature (°F). 🔥 marks each city's hottest month, ❄️ its coldest; shading runs cool blue to warm red.
The same figures plotted out, so the shape of a typical year is easier to see than in a grid. Where the two lines run close together Phoenix and Seattle feel alike; where they separate, they are genuinely different places to be.
Hover or tap any point to read the exact figures. Phoenix Seattle
See how Phoenix and Seattle stack up against other cities. Swipe for more.
Choose which city to keep, then search for any other city in our database — we'll build the comparison for you.
Quick answers to the questions people ask most when comparing Phoenix and Seattle — each drawn straight from the climate figures above.
Phoenix is the warmer of the two. It averages daytime highs of 29.8°C (85.6°F) against 14.7°C (58.5°F) in Seattle — roughly 15.1°C (27.2°F) warmer by day. Nights are milder in Phoenix, with average lows of 14.8°C (58.6°F) versus 6.6°C (43.9°F).
Phoenix is hottest in July, averaging highs of about 40.6°C (105.1°F), while Seattle peaks in August at around 23.5°C (74.3°F). That makes Phoenix the hotter of the two at the height of summer.
Seattle gets colder. In its coldest month (December) overnight lows average about 1.3°C (34.4°F), compared with 5°C (41.1°F) at the low point of the year in Phoenix.
Seattle is the wetter city, collecting about 1,255 mm (49.4 in) of rain a year versus 294 mm (11.6 in) in Phoenix. Phoenix is wettest in August and driest in June; Seattle is wettest in November and driest in July.
Seattle is the more humid of the two, averaging 83% relative humidity over the year against 35% in Phoenix.
The most comfortable months in Phoenix are April, October and November, when average temperatures are at their mildest.
Seattle is at its most pleasant around July, August and September, based on the mildest average temperatures of the year.
Phoenix is the warmer city in all 12 months of the year. The gap is widest in June, about 16.2°C (29.2°F), and narrowest in January, about 7.5°C (13.5°F).
Phoenix has the bigger seasonal swing, about 21.5°C (38.7°F) between its coldest and hottest months versus 14.4°C (25.9°F) in Seattle — so Seattle has the steadier, more even climate.
On climate alone, Phoenix comes out ahead — it offers warmer days, less rain and lower humidity than Seattle. Seattle is the better fit only if you'd actually prefer cooler weather, more rainfall and a more humid climate.
Every figure on this page is calculated from NASA POWER satellite climate data spanning 1981–2025 (45 years). The averages describe the long-term climate of Phoenix and Seattle, not a single year's weather or a short-range forecast.
