Mid-May through late June, or September through mid-October. Late spring and early fall offer comfortable temperatures (spring highs ~60°F; fall highs ~66°F), smaller crowds than summer peak, lower hotel rates, and vibrant seasonal scenery — cherry blossoms in spring, foliage in fall. The Boston Marathon (April) and Head of the Charles Regatta (October) are signature events in the shoulder seasons. Summer (July–August) is warmest but most crowded and expensive
| Month | High (°F) | Low (°F) | Notes |
|---|---|---|---|
| Jan | 36 | 21 | crisp & changeable |
| Feb | 39 | 22 | crisp & changeable |
| Mar | 46 | 29 | cool & changeable |
| Apr | 57 | 40 | cool & changeable |
| May | 67 | 50 | mild & changeable |
| Jun | 76 | 59 | warm & changeable |
| Jul | 83 | 66 | warm & changeable |
| Aug | 81 | 65 | warm & changeable |
| Sep | 74 | 59 | warm & changeable |
| Oct | 62 | 49 | mild & changeable |
| Nov | 51 | 37 | cool & changeable |
| Dec | 42 | 28 | crisp & changeable |