Phoenix is 15.7°C (28.3°F) warmer by day, Phoenix has 10.3°C (18.5°F) warmer nights, Boston gets 919 mm (36.2 in) more rain a year.
Boston is at its warmest in July and coolest in January, while Phoenix peaks in July and bottoms out in January. Month for month, Phoenix is the warmer of the two in 12 of 12 months.
Boston is the wetter of the two, collecting 1,213 mm (47.8 in) of rain a year against 294 mm (11.6 in) in Phoenix. The most comfortable time to visit is June, July and August in Boston and April, October and November in Phoenix.
| Boston | Metric | Phoenix |
|---|---|---|
| 🌡️ Temperature | ||
| 57.4°F | 🌡️Average daytime high | 85.6°F |
| 40.1°F | 🌙Average nighttime low | 58.6°F |
| July | 🔥Hottest month | July |
| January | ❄️Coldest month | January |
| 🌧️ Rain | ||
| 47.8 in | 🌧️Annual rainfall | 11.6 in |
| October | ☔Wettest month | August |
| February | 🏜️Driest month | June |
| 💨 Climate | ||
| 80% | 💧Average humidity | 35% |
| 0.7 m/s | 💨Average wind speed | 2 m/s |
Overnight, Boston typically falls to around 4.5°C (40.1°F) while Phoenix settles near 14.8°C (58.6°F).
Boston is hottest in July and coldest in January, whereas Phoenix peaks in July and is coolest in January.
Boston sees the most rain in October and the least in February; Phoenix is wettest in August and driest in June.
Boston feels the more humid of the two, averaging 80% relative humidity against 35%.
For Phoenix, the pick of the year is April, October and November.
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 | Boston | Phoenix | ||||
|---|---|---|---|---|---|---|
| Min | Avg | Max | Min | Avg | Max | |
| January | 17.8 | 25❄️ | 32.4 | 41 | 53.6❄️ | 66.2 |
| February | 19.4 | 27.1 | 34.9 | 43.2 | 56.1 | 69.3 |
| March | 26.4 | 34.7 | 43 | 47.3 | 61.5 | 75.6 |
| April | 35.8 | 45.1 | 54.5 | 53.4 | 68.7 | 84 |
| May | 46.4 | 55.9 | 65.5 | 62.4 | 77.9 | 93.4 |
| June | 55.9 | 65.1 | 74.3 | 72.7 | 88.3 | 104.2 |
| July | 62.4 | 71.8🔥 | 81.1 | 79.7 | 92.3🔥 | 105.1 |
| August | 61.3 | 71.1 | 80.8 | 79 | 91 | 103.1 |
| September | 54.1 | 64 | 73.8 | 72.7 | 85.8 | 98.8 |
| October | 43.7 | 52.5 | 61.5 | 60.8 | 74.3 | 87.8 |
| November | 33.8 | 41.5 | 49.3 | 49.5 | 62.4 | 75.4 |
| December | 24.8 | 31.5 | 38.1 | 41.5 | 53.8 | 65.8 |
| Annual Avg | 40.1 | 48.7 | 57.4 | 58.6 | 72.1 | 85.6 |
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 Boston and Phoenix feel alike; where they separate, they are genuinely different places to be.
Hover or tap any point to read the exact figures. Boston Phoenix
See how Boston and Phoenix 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 Boston and Phoenix — 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 14.1°C (57.4°F) in Boston — roughly 15.7°C (28.3°F) warmer by day. Nights are milder in Phoenix, with average lows of 14.8°C (58.6°F) versus 4.5°C (40.1°F).
Boston is hottest in July, averaging highs of about 27.3°C (81.1°F), while Phoenix peaks in July at around 40.6°C (105.1°F). That makes Phoenix the hotter of the two at the height of summer.
Boston gets colder. In its coldest month (January) overnight lows average about -7.9°C (17.7°F), compared with 5°C (41.1°F) at the low point of the year in Phoenix.
Boston is the wetter city, collecting about 1,213 mm (47.8 in) of rain a year versus 294 mm (11.6 in) in Phoenix. Boston is wettest in October and driest in February; Phoenix is wettest in August and driest in June.
Boston is the more humid of the two, averaging 80% relative humidity over the year against 35% in Phoenix.
The most comfortable months in Boston are June, July and August, when average temperatures are at their mildest.
Phoenix is at its most pleasant around April, October and November, 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 February, about 16.1°C (29°F), and narrowest in August, about 11.1°C (20°F).
Boston has the bigger seasonal swing, about 26°C (46.8°F) between its coldest and hottest months versus 21.5°C (38.7°F) in Phoenix — so Phoenix has the steadier, more even climate.
On climate alone, Phoenix comes out ahead — it offers warmer days, less rain and lower humidity than Boston. Boston 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 Boston and Phoenix, not a single year's weather or a short-range forecast.
