Boston vs Portland: which is sunnier?
🇺🇸 United States vs 🇺🇸 United States · 154 km apart · long-term climate normals (NASA POWER, 2001–2020)
Boston and Portland are virtually tied for annual sunshine — about 2,157 vs 2,150 hours a year. Boston has the higher Sunshine Score in 6 of 12 months; the other 6 are within 2 points.
Scores are the 0–100 Sunshine Score — sunshine, daytime warmth and dryness in one number, per month.
At a glance
| Boston | Portland | |
|---|---|---|
| Sunshine hours / year | 2,157 | 2,150 |
| Sunniest month | July (74/100) | July (74/100) |
| Nov–Feb average score | 3/100 | 2/100 |
| Jun–Aug average score | 73/100 | 66/100 |
| Rain / year | 1,207 mm | 1,363 mm |
| Warmest sea | 20°C / 68°F | 20°C / 68°F |
| Peak midday UV | 7 (high) | 7 (high) |
Boston vs Portland month by month
| Month | Sunshine Score | Day high °C | Rain mm | Sea °C | ||||
|---|---|---|---|---|---|---|---|---|
| Boston | Portland | Boston | Portland | Boston | Portland | Boston | Portland | |
| January | 0 | 0 | 1° | 1° | 80 | 103 | 4° | 5° |
| February | 0 | 0 | 2° | 1° | 86 | 103 | 4° | 3° |
| March | 0 | 0 | 6° | 4° | 110 | 110 | 5° | 4° |
| April | 30 | 0 | 13° | 8° | 107 | 121 | 8° | 7° |
| May | 68 | 24 | 19° | 12° | 95 | 101 | 13° | 12° |
| June | 71 | 51 | 24° | 17° | 113 | 127 | 18° | 17° |
| July | 74 | 74 | 28° | 21° | 94 | 96 | 19° | 18° |
| August | 74 | 74 | 28° | 21° | 93 | 94 | 20° | 20° |
| September | 74 | 61 | 24° | 18° | 92 | 97 | 19° | 18° |
| October | 52 | 27 | 17° | 13° | 123 | 145 | 15° | 14° |
| November | 12 | 6 | 10° | 9° | 98 | 125 | 10° | 10° |
| December | 0 | 0 | 4° | 4° | 116 | 141 | 6° | 7° |
The sunnier month by month: Jan even · Feb even · Mar even · Apr Boston · May Boston · Jun Boston · Jul even · Aug even · Sep Boston · Oct Boston · Nov Boston · Dec even.
When to pick which
- November–February: too close to call — Boston averages 3/100, Portland 2/100. Daytime highs are similar (4°C vs 4°C). See the winter sun ranking.
- March–May: Boston (average score 33/100 vs 8). Boston is the warmer, around 13°C daytime highs vs 8°C.
- June–August: Boston (average score 73/100 vs 66). Boston is the warmer, around 27°C daytime highs vs 20°C.
- September–October: Boston (average score 63/100 vs 44). Boston is the warmer, around 21°C daytime highs vs 16°C.
Sea temperature
Both seas peak at 20°C / 68°F. Swimmable water (21°C+): Boston never, Portland never. Month-by-month sea temperatures are in the table above.
Full month-by-month guides: Boston weather by month · Portland weather by month · Best time to visit United States.
More comparisons: Boston vs Providence/Warwick · Boston vs Manchester · Boston vs Martha's Vineyard · Portland vs Manchester · Portland vs Bangor · all head-to-heads