Bath, Maine climate: Normal weather by month, frost dates and records
Bath's normal year runs from 10°F January nights to 79°F July afternoons, with 48.5 inches of precipitation and 72 inches of snow a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 7.0°C, January lows of −12°C, July highs of 26°C, 1,231 mm of precipitation a year.
- NOAA stationBath
- Station IDUSC00170409
- Location43.93°N 69.86°W
- Elevation25 ft (8 m)
- Population8,817
On October 9, the normal high in Bath is 61°F and the normal low 40°F, and the chance of measurable rain or snow is 35%.
Normals describe a typical year at the station, not a forecast. The National Weather Service forecast for Bath.
- Jan 31° 10°
- Feb 34° 10°
- Mar 41° 20°
- Apr 53° 31°
- May 63° 41°
- Jun 72° 51°
- Jul 79° 57°
- Aug 78° 56°
- Sep 71° 48°
- Oct 59° 38°
- Nov 47° 28°
- Dec 37° 18°
Each month: normal high (large) and low, °F. Fill: the month's normal mean, colder blue to hotter red.
What is the weather like in Bath each month?
July is the warmest month, with normal highs of 79°F; January the coldest, with normal lows of 10°F. The most precipitation falls in October (5.25 in), the least in July (3.14 in).
| Month | High | Low | Mean | Precip. | Snow | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|---|
| January | 31°F | 10°F | 20.7°F | 3.74 | 20.0 | 12 | <1 | 30 | 9 h 10 min |
| February | 34°F | 10°F | 21.5°F | 3.58 | 18.8 | 10 | <1 | 27 | 10 h 30 min |
| March | 41°F | 20°F | 30.6°F | 4.16 | 13.4 | 11 | <1 | 27 | 11 h 50 min |
| April | 53°F | 31°F | 41.8°F | 4.31 | 3.0 | 12 | <1 | 18 | 13 h 20 min |
| May | 63°F | 41°F | 52.0°F | 3.56 | 0.0 | 13 | <1 | 2 | 14 h 40 min |
| June | 72°F | 51°F | 61.7°F | 4.42 | 0.0 | 12 | <1 | <1 | 15 h 30 min |
| July | 79°F | 57°F | 68.0°F | 3.14 | 0.0 | 11 | 1 | <1 | 15 h 10 min |
| August | 78°F | 56°F | 66.9°F | 3.26 | 0.0 | 10 | 1 | <1 | 14 h |
| September | 71°F | 48°F | 59.3°F | 3.92 | 0.0 | 10 | <1 | 1 | 12 h 40 min |
| October | 59°F | 38°F | 48.0°F | 5.25 | 0.1 | 11 | <1 | 7 | 11 h 10 min |
| November | 47°F | 28°F | 37.2°F | 4.52 | 2.5 | 11 | <1 | 22 | 9 h 40 min |
| December | 37°F | 18°F | 27.1°F | 4.59 | 14.0 | 13 | <1 | 28 | 9 h |
| Year (annual) | 55°F | 34°F | 44.6°F | 48.45 | 71.8 | 135 | 2 | 162 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. | Snow |
|---|---|---|---|---|---|
| January | 0°C | −12°C | −6.3°C | 95 mm | 51 cm |
| February | 1°C | −12°C | −5.8°C | 91 mm | 48 cm |
| March | 5°C | −6°C | −0.8°C | 106 mm | 34 cm |
| April | 11°C | −1°C | 5.4°C | 109 mm | 8 cm |
| May | 17°C | 5°C | 11.1°C | 90 mm | 0 cm |
| June | 22°C | 11°C | 16.5°C | 112 mm | 0 cm |
| July | 26°C | 14°C | 20.0°C | 80 mm | 0 cm |
| August | 26°C | 13°C | 19.4°C | 83 mm | 0 cm |
| September | 21°C | 9°C | 15.2°C | 100 mm | 0 cm |
| October | 15°C | 3°C | 8.9°C | 133 mm | 0 cm |
| November | 8°C | −2°C | 2.9°C | 115 mm | 6 cm |
| December | 3°C | −8°C | −2.7°C | 117 mm | 36 cm |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00170409; annual normals. Wet days: 0.01 inch or more; 90°F days and freezing nights: NOAA's day counts. Daylight: sunrise to sunset on the 15th, computed from the latitude.
When is the best weather to visit Bath?
Normal highs sit between 65°F and 85°F in June, July, August and September. Of those, August has the fewest days with rain (10).
That is a measurement, not a recommendation: it counts the months whose normal afternoon high sits between 65°F and 85°F, where a light layer is enough by day.
Source: NOAA NCEI 1991-2020 monthly normals, station USC00170409.
When is the last frost in Bath?
In Bath, the last spring frost (32°F) comes after May 10 in half of years and after May 23 in one year in ten; the first autumn frost comes before October 6 in half of years and before September 25 in one year in ten.
Frost-free in half of yearsFrost in 1 to 9 years out of 10Frost most years
- Last spring frost, half of years after
- May 101 year in 10 after May 23; 9 in 10 after April 28
- First autumn frost, half of years before
- October 61 year in 10 before September 25; 9 in 10 before October 21
NOAA puts the median frost-free season at 149 days, and the season without a hard freeze (28°F) at 172 days.
A hard freeze (28°F) comes after April 29 in half of springs and before October 19 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts Bath in zone 6a in ZIP code 04530. By the map's own method, the average of each year's coldest night over 1991-2020, Bath's NOAA station is in zone 5b: the coldest night of a typical year reaches −13°F (20 complete years); the map interpolates between stations and terrain, so the station and the ZIP area can differ by half a zone.
Frost dates for every NOAA station in Maine · Frost dates by ZIP code
Source: NOAA NCEI 1991-2020 annual normals (frost probabilities), station USC00170409; USDA 2023 Plant Hardiness Zone Map, ZIP listings: PRISM Group, Oregon State University, https://prism.oregonstate.edu, accessed October 8, 2026; the station zone: ACIS daily lows, 1991-2020. A 10% date means one year in ten has a frost after it in spring or before it in autumn.
How hot and how cold does it get in Bath?
In a normal year in Bath, 2 days a year reach 90°F, 162 nights fall to 32°F or colder and 135 days bring measurable precipitation.
- Days at 90°F or more
- 2a normal year
- Days at 100°F or more
- fewer than 1a normal year
- Nights at 32°F or colder
- 162a normal year
- Days that stay below freezing
- 46high of 32°F or less
- Days with 0.01 inch of precipitation
- 135a normal year
- Days with 1 inch of snow or more
- 20a normal year
The highest temperature in this station's record (since 2000) is 97°F, on July 23, 2011; the lowest is −23°F, on January 4, 2014.
The wettest calendar year on that record is 2005, with 71.63 in; the snowiest season is 2014–15, with 114.0 inches.
Source: NOAA NCEI 1991-2020 annual normals, station USC00170409; records: ACIS (NOAA Regional Climate Centers), station USC00170409. Records use complete months only; a month missing more than three days is left out.
How sunny is Bath?
Over a year 73% of the sunlight that would reach the ground under clear skies gets through the clouds in the area around Bath, 3.8 kWh per square metre a day. August is the sunniest month (81%) and December the cloudiest (62%).
| Month | Share of clear-sky sunshine | Sunshine, kWh/m² a day |
|---|---|---|
| January | 64% | 1.6 |
| February | 69% | 2.5 |
| March | 70% | 3.7 |
| April | 70% | 4.8 |
| May | 70% | 5.5 |
| June | 72% | 5.8 |
| July | 79% | 6.0 |
| August | 81% | 5.5 |
| September | 80% | 4.4 |
| October | 71% | 2.8 |
| November | 67% | 1.8 |
| December | 62% | 1.3 |
Source: NASA POWER solar climatology, 2001-2020 (CERES SYN1deg). Satellite-based, for the 1-degree cell (about 100 km across) around the station, so it describes the area rather than the airport.
How much heating and cooling does Bath need?
A normal year in Bath brings 7,668 heating degree days, 43% more than the median U.S. place (5,373), and 259 cooling degree days, 71% fewer than the median (908). Eight months need 300 or more heating degree days, a monthly mean of about 55°F or colder. For gardens and crops, NOAA counts 1,918 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 1,373 | 0 |
| February | 1,216 | 0 |
| March | 1,066 | 0 |
| April | 698 | 0 |
| May | 405 | 2 |
| June | 129 | 29 |
| July | 20 | 113 |
| August | 29 | 88 |
| September | 197 | 27 |
| October | 526 | 0 |
| November | 834 | 0 |
| December | 1,175 | 0 |
| Year (annual) | 7,668 | 259 |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00170409. A degree day is one degree of a day's mean temperature below 65°F (heating) or above it (cooling); utilities use them to estimate energy use.
Has Bath been warmer than normal lately?
2025 averaged 45.3°F, 0.7°F above the 1991-2020 normal of 44.6°F. 4 of the 4 complete years since 2022 ran warmer than the normal.
| Year | Mean | Against normal | Precip. | Snow |
|---|---|---|---|---|
| 2022 | 46.4°F | +1.8°F | 50.29 | 48.1 |
| 2023 | 47.3°F | +2.7°F | 61.14 | 63.8 |
| 2024 | 47.5°F | +2.9°F | 48.09 | 53.0 |
| 2025 | 45.3°F | +0.7°F | 42.01 | 70.7 |
Source: observed years: ACIS, station USC00170409. A year counts only with all twelve months complete.
How does Bath's climate compare?
Bath is warmer than 23 of the other 41 places with their own NOAA record in Maine, and wetter than 28. Across the 7,247 U.S. stations with normals, its annual mean of 44.6°F is warmer than 18%.
In the Köppen classification computed from these normals, Bath is Dfb: continental, no dry season, warm summer. What the classes mean.
Places with the most similar year elsewhere
Measured month by month on the normal high, low and precipitation, among places of 20,000 or more people in other states:
Source: NOAA NCEI 1991-2020 normals for every station PlainClimate covers. Similarity: the root-mean-square difference of the 36 monthly figures, precipitation weighted so an inch counts like 6°F.
Which places near Bath share this climate record?
Bowdoinham has no NOAA station with 1991-2020 normals of its own, and this station is the nearest full record. A place's own climate can differ from these figures, by several degrees where it sits much higher or lower than the station, nearer the coast, or inside a large city's heat; for the larger places the next nearest records are named with their yearly mean, so the spread around them is visible, and places of 50,000 or more have their own page with NOAA's gridded normals.
- Bowdoinham, ME3,190 people · 7 mi N
Source: Census Bureau 2024 Gazetteer (place centers) and Vintage 2024 population estimates. Distance and direction from the station to each place's center.
Questions about Bath's climate
What is the coldest month in Bath?
January, with a normal high of 31°F and a normal low of 10°F. The warmest is July (79°F by day, 57°F at night).
Does it snow in Bath?
Yes: 72 inches in a normal year, falling on 28 days with 0.1 inch or more, the most in January (20.0 inches).
What is the rainiest month in Bath?
October, with 5.25 in of precipitation in a normal year; the driest is July with 3.14 in.
What plant hardiness zone is Bath in?
The USDA's 2023 map puts Bath in zone 6a in ZIP code 04530. By the same method at Bath's NOAA station, the coldest night of a typical year reaches −13°F (20 years, 1991-2020): zone 5b.
How late can frost come in Bath?
In half of years the last 32°F night comes after May 10; in one year in ten it comes after May 23. Waiting until May 23 leaves about a one-in-ten chance of a later frost.
Nearby and next
- Maine climateThe statewide normals and every place in the state
- Brunswick, ME4 miles from this station, 45.7°F a year
- Wiscasset, ME7 miles from this station, 45.9°F a year
- Westport Island, ME8 miles from this station, 46.0°F a year
- Durham, ME13 miles from this station, 43.9°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made