Hardly any U.S. towns see fresher July days than Siasconset
The depth of winter brings overnight lows near 26°. Seasons differ by 49°, from the coldest nights to the warmest afternoons. In January, nights here are milder than in 67% of U.S. towns. Tender plants can go out after about April 13; in half of years the first frost comes by November 8.
A year in Siasconset at a glance
Each month’s typical high and low, and what it brings.
What stands out about Siasconset’s climate
Compared with towns across the U.S., with Siasconset’s place in Massachusetts beside it.
What a year in Siasconset feels like
Typical highs and lows by season and by month, from NOAA’s 30-year normals.
About 208 frost-free days a year
In half of years the last 32° night comes by April 13 and the first by November 8. Frost and day counts come from NOAA’s station at Nantucket Mem Airport, 5 miles from the town’s center, at about the same height.
The 2023 USDA map puts Siasconset’s center in zone 7b: the coldest night of a typical winter, averaged over 1991–2020, reaches about 8°. Plant labels use the zone; frost dates tell you when to plant.
Freezing nights by month
Average nights at or below 32°
About 44 inches of rain a year
October is the wettest month and July the driest.
Rain + melted snow by month
Inches of water
Heating and cooling a home in Siasconset
94% of the work is heating, so the furnace matters far more than the air conditioner. Months averaging under 55° run from October through May.
Degree days add up how far each day’s average falls below (heating) or rises above (cooling) 65° over a year. NOAA normals at Nantucket Mem Airport.
Living with Siasconset’s climate
What the numbers mean for a garden, a free afternoon and a bad-weather day.
208 frost-free days in zone 7b. The last frost comes by Apr 13 in half of years, so many gardeners wait a week or two past that to set out tomatoes. The first fall frost comes by Nov 8.
Months with highs of 62–84° and lows of 40° or more: June, July, August and September. 9.1 miles of trails are waiting.
Parks & trails →Of the yearly building losses FEMA expects in Siasconset from natural hazards, hurricanes are the largest share (79%). Normals are averages; the hazards page covers the extremes.
Natural hazards →Siasconset and similar climates
TownRatings has no climate map of the towns around Siasconset yet.
Temperatures and precipitation come from NOAA’s 5 km grid; snow and day counts from the stations named on this page.
Warmer than it used to be
The last 30 years in Siasconset averaged 2.1° warmer than the 1900s. The biggest change is in December (+3.4°).
A bigger shift than in 93% of U.S. towns.
Change by month
The two periods overlap (1991–2000 is in both), which makes the gap a little smaller than it would be between separate periods.
How Siasconset compares
Against 12,954 U.S. towns of 2,500 or more (one per 5 km climate cell), with Siasconset’s place among Massachusetts’.
Siasconset weather by month
Highs, lows and precipitation from NOAA’s grid at Siasconset’s center. 1991–2020 normals.
| Month | High | Low | Rain + melt | 30-yr range |
|---|---|---|---|---|
| January | 39° | 26° | 3.7" | 24° – 39° |
| February | 40° | 27° | 3.2" | 25° – 39° |
| March | 44° | 32° | 4.1" | 33° – 44° |
| April | 52° | 39° | 4.0" | 41° – 49° |
| May | 60° | 47° | 3.2" | 49° – 57° |
| June | 69° | 56° | 3.2" | 59° – 66° |
| July | 76° | 63° | 2.4" | 65° – 72° |
| August | 76° | 63° | 3.3" | 66° – 73° |
| September | 70° | 57° | 3.8" | 61° – 68° |
| October | 62° | 48° | 4.4" | 52° – 60° |
| November | 53° | 40° | 4.0" | 42° – 51° |
| December | 45° | 32° | 4.4" | 32° – 48° |
| Year | 57° | 44° | 43.6" |
How much a month can swing
A normal is an average. December swings the most: from 1991 to 2020 its average ranged from 32° to 48°. September is the most reliable, staying within 6°.
Where Siasconset’s numbers come from
Normals are 30-year averages, not a forecast. How TownRatings reads climate data →
- Temperatures and precipitation: NOAA’s gridded 1991–2020 normals for the 5 km cell at Siasconset’s center.
- Frost, freezing nights, 90° and 100° days, heating and cooling: Nantucket Mem Airport, 5 miles from the town’s center, at about the same height; the nearest station that passes our checks for distance, height and agreement with the grid.
- Growing zone: USDA Plant Hardiness Zone Map, 2023. USDA Agricultural Research Service and PRISM Group, Oregon State University, prism.oregonstate.edu/phzm, accessed 8 Oct 2026.
- Then and now: NOAA’s gridded normals for 1901–2000 at the same cell.
- Storms and extremes: FEMA National Risk Index (expected annual losses to buildings).
Common questions about Siasconset’s climate
What is the weather like in Siasconset?
A typical July afternoon reaches 76°, a January night drops to 26°. Milder January nights than 67% of U.S. towns; cooler July afternoons than 98% of U.S. towns.
How cold does it get in Siasconset in winter?
January nights average 26°. About 86 nights a year reach 32° or below. In the coldest January of the last 30 years the month averaged 24°.
How hot does it get in Siasconset?
July, with a typical high of 76°. 90° days are rare: none in a normal year at Nantucket Mem Airport.
When is the first and last frost in Siasconset?
In half of years the last spring frost (32°) comes by April 13 and the first fall frost by November 8, about 208 frost-free days, at Nantucket Mem Airport.
What growing zone is Siasconset in?
Zone 7b on the 2023 USDA Plant Hardiness Zone Map: the coldest night of a typical winter reaches about 8°.
What is the best time of year to visit Siasconset?
By one simple rule (highs of 62–84° and lows of 40° or more), June, July, August and September. The rule is ours, not NOAA’s; the month table has the numbers to judge by.
Is Siasconset getting warmer?
Yes: 1991–2020 averaged 2.1° warmer than 1901–2000 on NOAA’s grid. A bigger shift than 93% of U.S. towns.
Neighbors talk weather
Gardens, snow, and the best days of the year in Siasconset.
Source: NOAA NCEI U.S. Climate Normals, 1991–2020 and 1901–2000; USDA/PRISM 2023 hardiness zones; FEMA National Risk Index. Today’s forecast: National Weather Service.