Johnston weather in December
In December, Johnston sees average daytime highs of 42°F and overnight lows near 29°F, with 4.3 in of precipitation across 10.4 wet days and about 9 hours of daylight. It is the 10th-warmest and 2nd-wettest month of the year here.
Highs ease over the month, from about 45°F in the first days to 39°F by the end. The sky is clear or mostly clear about 32% of the time in December, and the air most often feels dry.
Daylight stretches from about 9 h 12 min at the start of December to 9 hours by month's end. Set against the rest of the year, December is Johnston's 7th-clearest and 4th-windiest month. For the whole year in context, see Johnston's year-round climate.
- Daytime high
- 42°
- 10th warmest
- Overnight low
- 29°
- 3rd coldest
- Precipitation
- 4.3 in
- 10.4 wet days
- Daylight
- 9 hours
- 7:13 AM – 4:11 PM
- Cloud cover
- 59%
- 7th clearest
- Wind
- 8 mph
- 4th windiest
- Solar energy
- 1.66 kWh/m²
- Travel score
- 0.3
- out of 10
Temperature in December
Highs ease over the month, from about 45°F in the first days to 39°F by the end.
A typical December day in Johnston reaches about 42°F in the afternoon and slips back to 29°F overnight — a 13°F spread between the day's warmth and the night's chill. On most days the high lands between 30°F and 55°F. Set against its neighbours, December runs about 9°F cooler than November and about 5°F warmer than January.
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg high (°F) | 46 | 46 | 45 | 45 | 45 | 44 | 44 | 44 | 43 | 43 | 42 | 42 | 42 | 42 | 42 | 41 | 41 | 41 | 41 | 41 | 41 | 40 | 40 | 40 | 40 | 40 | 40 | 40 | 39 | 39 | 39 |
| Avg low (°F) | 33 | 32 | 32 | 32 | 31 | 31 | 31 | 30 | 30 | 30 | 29 | 29 | 29 | 29 | 29 | 28 | 28 | 28 | 28 | 28 | 28 | 28 | 27 | 27 | 27 | 27 | 27 | 26 | 26 | 26 | 26 |
| Avg high (°F) | Avg low (°F) | |
|---|---|---|
| 1 | 46 | 33 |
| 2 | 46 | 32 |
| 3 | 45 | 32 |
| 4 | 45 | 32 |
| 5 | 45 | 31 |
| 6 | 44 | 31 |
| 7 | 44 | 31 |
| 8 | 44 | 30 |
| 9 | 43 | 30 |
| 10 | 43 | 30 |
| 11 | 42 | 29 |
| 12 | 42 | 29 |
| 13 | 42 | 29 |
| 14 | 42 | 29 |
| 15 | 42 | 29 |
| 16 | 41 | 28 |
| 17 | 41 | 28 |
| 18 | 41 | 28 |
| 19 | 41 | 28 |
| 20 | 41 | 28 |
| 21 | 41 | 28 |
| 22 | 40 | 28 |
| 23 | 40 | 27 |
| 24 | 40 | 27 |
| 25 | 40 | 27 |
| 26 | 40 | 27 |
| 27 | 40 | 27 |
| 28 | 40 | 26 |
| 29 | 39 | 26 |
| 30 | 39 | 26 |
| 31 | 39 | 26 |
How December really feels in Johnston
Once humidity and wind are folded in, December averages 0 days that feel above 90°F and 31 that feel at or below 32°F — the comfort signal a plain temperature reading hides.
The story in December is cold — wind chill drags the overnight "feels like" below the raw low.
Johnston weather by month
How December compares with the rest of the year at a glance. December is the 10th-warmest and 2nd-wettest month here — the current month is highlighted below.
| Month | High / Low (°F) | Rainfall (inches) | Wet days | Snow days | Daylight (hours) | Travel score |
|---|---|---|---|---|---|---|
| Jan | 37° / 23° | 3.6 | 10 | 5.2 | 9.3 | 0.0 |
| Feb | 39° / 24° | 3.1 | 8.6 | 4.8 | 10.3 | 0.0 |
| Mar | 46° / 31° | 4.4 | 10.7 | 4.3 | 11.7 | 1.2 |
| Apr | 57° / 41° | 3.8 | 10.8 | 0.7 | 13.1 | 3.9 |
| May | 67° / 50° | 3.1 | 10.8 | 0 | 14.3 | 5.9 |
| Jun | 76° / 60° | 3.5 | 10.1 | 0 | 15 | 6.7 |
| Jul | 82° / 66° | 3.2 | 10.6 | 0 | 14.7 | 6.3 |
| Aug | 80° / 64° | 3.8 | 10.3 | 0 | 13.7 | 6.5 |
| Sep | 73° / 57° | 3.6 | 8.3 | 0 | 12.3 | 7.0 |
| Oct | 62° / 47° | 4.1 | 9.3 | 0.2 | 10.9 | 5.4 |
| Nov | 51° / 37° | 3.5 | 8.8 | 0.8 | 9.6 | 2.7 |
| Dec | 42° / 29° | 4.3 | 10.4 | 4 | 9 | 0.3 |
Cloud cover in December
The sky is clear or mostly clear about 32% of the time in December.
Beyond those clear spells, partly cloudy skies cover about 15% of December, with mostly cloudy or overcast conditions the remaining 53%.
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Clearer (%) | 49 | 49 | 49 | 48 | 48 | 47 | 47 | 47 | 47 | 46 | 45 | 45 | 45 | 44 | 44 | 45 | 45 | 45 | 45 | 45 | 45 | 46 | 48 | 48 | 47 | 47 | 49 | 49 | 48 | 48 | 49 |
| Cloudier (%) | 51 | 51 | 51 | 52 | 52 | 53 | 53 | 53 | 53 | 54 | 55 | 55 | 55 | 56 | 56 | 55 | 55 | 55 | 55 | 55 | 55 | 54 | 52 | 52 | 53 | 53 | 51 | 51 | 52 | 52 | 51 |
| Clearer (%) | Cloudier (%) | |
|---|---|---|
| 1 | 49 | 51 |
| 2 | 49 | 51 |
| 3 | 49 | 51 |
| 4 | 48 | 52 |
| 5 | 48 | 52 |
| 6 | 47 | 53 |
| 7 | 47 | 53 |
| 8 | 47 | 53 |
| 9 | 47 | 53 |
| 10 | 46 | 54 |
| 11 | 45 | 55 |
| 12 | 45 | 55 |
| 13 | 45 | 55 |
| 14 | 44 | 56 |
| 15 | 44 | 56 |
| 16 | 45 | 55 |
| 17 | 45 | 55 |
| 18 | 45 | 55 |
| 19 | 45 | 55 |
| 20 | 45 | 55 |
| 21 | 45 | 55 |
| 22 | 46 | 54 |
| 23 | 48 | 52 |
| 24 | 48 | 52 |
| 25 | 47 | 53 |
| 26 | 47 | 53 |
| 27 | 49 | 51 |
| 28 | 49 | 51 |
| 29 | 48 | 52 |
| 30 | 48 | 52 |
| 31 | 49 | 51 |
Chance of precipitation in December
Johnston gets around 4.3 in of rain and snow over 10.4 wet days in December. The line is the day-by-day chance of measurable precipitation.
Day to day, the chance of measurable precipitation averages around 33% and peaks near 34% on the wettest days, and about 4 days bring snow.
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Rain chance (%) | 31 | 32 | 32 | 32 | 33 | 33 | 33 | 33 | 34 | 34 | 34 | 34 | 34 | 34 | 34 | 33 | 33 | 33 | 33 | 33 | 33 | 33 | 33 | 33 | 33 | 33 | 33 | 34 | 34 | 34 | 34 |
| Snow chance (%) | 9 | 10 | 11 | 11 | 12 | 13 | 13 | 13 | 14 | 14 | 14 | 14 | 14 | 14 | 13 | 13 | 13 | 12 | 12 | 12 | 12 | 12 | 12 | 12 | 12 | 12 | 13 | 13 | 13 | 14 | 15 |
| Rain chance (%) | Snow chance (%) | |
|---|---|---|
| 1 | 31 | 9 |
| 2 | 32 | 10 |
| 3 | 32 | 11 |
| 4 | 32 | 11 |
| 5 | 33 | 12 |
| 6 | 33 | 13 |
| 7 | 33 | 13 |
| 8 | 33 | 13 |
| 9 | 34 | 14 |
| 10 | 34 | 14 |
| 11 | 34 | 14 |
| 12 | 34 | 14 |
| 13 | 34 | 14 |
| 14 | 34 | 14 |
| 15 | 34 | 13 |
| 16 | 33 | 13 |
| 17 | 33 | 13 |
| 18 | 33 | 12 |
| 19 | 33 | 12 |
| 20 | 33 | 12 |
| 21 | 33 | 12 |
| 22 | 33 | 12 |
| 23 | 33 | 12 |
| 24 | 33 | 12 |
| 25 | 33 | 12 |
| 26 | 33 | 12 |
| 27 | 33 | 13 |
| 28 | 34 | 13 |
| 29 | 34 | 13 |
| 30 | 34 | 14 |
| 31 | 34 | 15 |
Humidity in December
Most of December feels dry — the stacked bands show each day's mix of comfort levels, read off the dew point.
By dew point, December lands in the dry band about 100% of days. It rarely turns muggy — the humid and sticky bands barely register.
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Dry (%) | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 |
| Dry (%) | |
|---|---|
| 1 | 100 |
| 2 | 100 |
| 3 | 100 |
| 4 | 100 |
| 5 | 100 |
| 6 | 100 |
| 7 | 100 |
| 8 | 100 |
| 9 | 100 |
| 10 | 100 |
| 11 | 100 |
| 12 | 100 |
| 13 | 100 |
| 14 | 100 |
| 15 | 100 |
| 16 | 100 |
| 17 | 100 |
| 18 | 100 |
| 19 | 100 |
| 20 | 100 |
| 21 | 100 |
| 22 | 100 |
| 23 | 100 |
| 24 | 100 |
| 25 | 100 |
| 26 | 100 |
| 27 | 100 |
| 28 | 100 |
| 29 | 100 |
| 30 | 100 |
| 31 | 100 |
Wind in December
Winds average 8 mph in December.
Across December, daily wind ranges from about 8 mph on the calmest days to 8 mph at its breeziest. It stays fairly steady from day to day.
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Wind speed (mph) | 8 | 8 | 8 | 8 | 8 | 8 | 8 | 8 | 8 | 8 | 8 | 8 | 8 | 8 | 8 | 8 | 8 | 8 | 8 | 8 | 8 | 8 | 8 | 8 | 8 | 8 | 8 | 8 | 8 | 8 | 8 |
| Feels | light breeze | light breeze | light breeze | light breeze | light breeze | light breeze | light breeze | light breeze | light breeze | light breeze | light breeze | light breeze | light breeze | light breeze | light breeze | light breeze | light breeze | light breeze | light breeze | light breeze | light breeze | light breeze | light breeze | light breeze | light breeze | light breeze | light breeze | light breeze | light breeze | light breeze | light breeze |
| Wind speed (mph) | Feels | |
|---|---|---|
| 1 | 8 | light breeze |
| 2 | 8 | light breeze |
| 3 | 8 | light breeze |
| 4 | 8 | light breeze |
| 5 | 8 | light breeze |
| 6 | 8 | light breeze |
| 7 | 8 | light breeze |
| 8 | 8 | light breeze |
| 9 | 8 | light breeze |
| 10 | 8 | light breeze |
| 11 | 8 | light breeze |
| 12 | 8 | light breeze |
| 13 | 8 | light breeze |
| 14 | 8 | light breeze |
| 15 | 8 | light breeze |
| 16 | 8 | light breeze |
| 17 | 8 | light breeze |
| 18 | 8 | light breeze |
| 19 | 8 | light breeze |
| 20 | 8 | light breeze |
| 21 | 8 | light breeze |
| 22 | 8 | light breeze |
| 23 | 8 | light breeze |
| 24 | 8 | light breeze |
| 25 | 8 | light breeze |
| 26 | 8 | light breeze |
| 27 | 8 | light breeze |
| 28 | 8 | light breeze |
| 29 | 8 | light breeze |
| 30 | 8 | light breeze |
| 31 | 8 | light breeze |
Sunrise & sunset in December
Daylight runs from about 9 h 12 min at the start of December to 9 hours by month's end. The lit band spans sunrise to sunset each day.
Days shrink by about 12 minutes over December. Sunrise moves from 7:00 AM to 7:19 AM, and sunset from 4:11 PM to 4:19 PM.
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Daylight (h) | 9.2 | 9.2 | 9.1 | 9.1 | 9.1 | 9.1 | 9.1 | 9.1 | 9.0 | 9.0 | 9.0 | 9.0 | 9.0 | 9.0 | 9.0 | 9.0 | 9.0 | 9.0 | 9.0 | 9.0 | 9.0 | 9.0 | 9.0 | 9.0 | 9.0 | 9.0 | 9.0 | 9.0 | 9.0 | 9.0 | 9.0 |
| Sunrise (AM) | 7:00 | 7:01 | 7:02 | 7:03 | 7:04 | 7:05 | 7:06 | 7:07 | 7:08 | 7:08 | 7:09 | 7:10 | 7:11 | 7:12 | 7:12 | 7:13 | 7:14 | 7:14 | 7:15 | 7:15 | 7:16 | 7:16 | 7:17 | 7:17 | 7:18 | 7:18 | 7:18 | 7:19 | 7:19 | 7:19 | 7:19 |
| Sunset (PM) | 4:11 | 4:11 | 4:11 | 4:11 | 4:11 | 4:10 | 4:10 | 4:10 | 4:10 | 4:10 | 4:11 | 4:11 | 4:11 | 4:11 | 4:11 | 4:11 | 4:12 | 4:12 | 4:12 | 4:13 | 4:13 | 4:14 | 4:14 | 4:15 | 4:15 | 4:16 | 4:16 | 4:17 | 4:18 | 4:18 | 4:19 |
| Daylight (h) | Sunrise (AM) | Sunset (PM) | |
|---|---|---|---|
| 1 | 9.2 | 7:00 | 4:11 |
| 2 | 9.2 | 7:01 | 4:11 |
| 3 | 9.1 | 7:02 | 4:11 |
| 4 | 9.1 | 7:03 | 4:11 |
| 5 | 9.1 | 7:04 | 4:11 |
| 6 | 9.1 | 7:05 | 4:10 |
| 7 | 9.1 | 7:06 | 4:10 |
| 8 | 9.1 | 7:07 | 4:10 |
| 9 | 9.0 | 7:08 | 4:10 |
| 10 | 9.0 | 7:08 | 4:10 |
| 11 | 9.0 | 7:09 | 4:11 |
| 12 | 9.0 | 7:10 | 4:11 |
| 13 | 9.0 | 7:11 | 4:11 |
| 14 | 9.0 | 7:12 | 4:11 |
| 15 | 9.0 | 7:12 | 4:11 |
| 16 | 9.0 | 7:13 | 4:11 |
| 17 | 9.0 | 7:14 | 4:12 |
| 18 | 9.0 | 7:14 | 4:12 |
| 19 | 9.0 | 7:15 | 4:12 |
| 20 | 9.0 | 7:15 | 4:13 |
| 21 | 9.0 | 7:16 | 4:13 |
| 22 | 9.0 | 7:16 | 4:14 |
| 23 | 9.0 | 7:17 | 4:14 |
| 24 | 9.0 | 7:17 | 4:15 |
| 25 | 9.0 | 7:18 | 4:15 |
| 26 | 9.0 | 7:18 | 4:16 |
| 27 | 9.0 | 7:18 | 4:16 |
| 28 | 9.0 | 7:19 | 4:17 |
| 29 | 9.0 | 7:19 | 4:18 |
| 30 | 9.0 | 7:19 | 4:18 |
| 31 | 9.0 | 7:19 | 4:19 |
Solar energy in December
Average shortwave solar energy reaching the ground each day in December, about 1.66 kWh/m² — the year's lowest.
For context, solar energy here swings from a low near 1.66 kWh/m² to a high of 5.93 kWh/m² in June across the year — December's 1.66 kWh/m² sits near the bottom.
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Solar energy (kWh/m²) | 1.8 | 1.8 | 1.8 | 1.7 | 1.7 | 1.7 | 1.7 | 1.7 | 1.7 | 1.7 | 1.7 | 1.6 | 1.6 | 1.6 | 1.6 | 1.6 | 1.6 | 1.6 | 1.6 | 1.6 | 1.6 | 1.6 | 1.6 | 1.7 | 1.7 | 1.7 | 1.7 | 1.7 | 1.7 | 1.7 | 1.7 |
| Level | Dim | Dim | Dim | Dim | Dim | Dim | Dim | Dim | Dim | Dim | Dim | Dim | Dim | Dim | Dim | Dim | Dim | Dim | Dim | Dim | Dim | Dim | Dim | Dim | Dim | Dim | Dim | Dim | Dim | Dim | Dim |
| Solar energy (kWh/m²) | Level | |
|---|---|---|
| 1 | 1.8 | Dim |
| 2 | 1.8 | Dim |
| 3 | 1.8 | Dim |
| 4 | 1.7 | Dim |
| 5 | 1.7 | Dim |
| 6 | 1.7 | Dim |
| 7 | 1.7 | Dim |
| 8 | 1.7 | Dim |
| 9 | 1.7 | Dim |
| 10 | 1.7 | Dim |
| 11 | 1.7 | Dim |
| 12 | 1.6 | Dim |
| 13 | 1.6 | Dim |
| 14 | 1.6 | Dim |
| 15 | 1.6 | Dim |
| 16 | 1.6 | Dim |
| 17 | 1.6 | Dim |
| 18 | 1.6 | Dim |
| 19 | 1.6 | Dim |
| 20 | 1.6 | Dim |
| 21 | 1.6 | Dim |
| 22 | 1.6 | Dim |
| 23 | 1.6 | Dim |
| 24 | 1.7 | Dim |
| 25 | 1.7 | Dim |
| 26 | 1.7 | Dim |
| 27 | 1.7 | Dim |
| 28 | 1.7 | Dim |
| 29 | 1.7 | Dim |
| 30 | 1.7 | Dim |
| 31 | 1.7 | Dim |
Hazard calendar for Johnston
None of Johnston's seasonal hazards are active in December. The full-year calendar below shows when the rainy season, cyclone risk and dust haze do peak.
Johnston sits in the Atlantic hurricane belt; the season peaks August–October.
Is December a good time to visit Johnston?
Our two travel scores rate December for general sightseeing and for beach or pool weather — 0 (poor) to 10 (ideal).
December is a weaker month for outdoor sightseeing in Johnston.
What to pack for Johnston in December
From December's temperature range, rain chance, sun and wind — what's worth putting in the bag.
In December, Johnston sees daytime highs around 42°F and nights near 29°F. Pack a warm layer and a heavy coat. Worth having: rain gear. About 10 days see rain.
Sea temperature near Johnston in December
The nearest coast averages about 48°F in December — the other half of the beach question. The full-year curve and swim-comfort zones are below.
The sea at the nearest coast (about 32 mi away) is warmest in August at about 69°F and coldest in February near 39°F.
It's comfortable for a long swim from Jul 29 to Aug 30 — about 1.1 months when the water holds above 68°F.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Sea temperature (°F) | 43 | 39 | 40 | 44 | 51 | 60 | 67 | 69 | 67 | 62 | 55 | 48 |
| Comfort | Bracing | Bracing | Bracing | Bracing | Bracing | Cool | Cool | Refreshing | Cool | Cool | Bracing | Bracing |
| Sea temperature (°F) | Comfort | |
|---|---|---|
| Jan | 43 | Bracing |
| Feb | 39 | Bracing |
| Mar | 40 | Bracing |
| Apr | 44 | Bracing |
| May | 51 | Bracing |
| Jun | 60 | Cool |
| Jul | 67 | Cool |
| Aug | 69 | Refreshing |
| Sep | 67 | Cool |
| Oct | 62 | Cool |
| Nov | 55 | Bracing |
| Dec | 48 | Bracing |
UV index in Johnston in December
Clear-sky midday UV in December peaks around 1. The full-year curve, shaded by WHO exposure level, is below.
Under clear skies, the midday UV index in Johnston peaks around July 10 at about 8 (very high) — sunscreen and a hat are worth it in the middle of the day. It bottoms out near January 1 at about 1 (low).
The index reaches 3 or more — the level where the WHO recommends sun protection — in 8 months of the year.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| UV index (midday) | 1 | 3 | 4 | 5 | 8 | 7 | 8 | 5 | 6 | 3 | 2 | 1 |
| Level | Low | Moderate | Moderate | High | Very high | Very high | Very high | Moderate | High | Moderate | Moderate | Low |
| UV index (midday) | Level | |
|---|---|---|
| Jan | 1 | Low |
| Feb | 3 | Moderate |
| Mar | 4 | Moderate |
| Apr | 5 | High |
| May | 8 | Very high |
| Jun | 7 | Very high |
| Jul | 8 | Very high |
| Aug | 5 | Moderate |
| Sep | 6 | High |
| Oct | 3 | Moderate |
| Nov | 2 | Moderate |
| Dec | 1 | Low |
Air quality in Johnston in December
Average fine-particle pollution (PM2.5) through the year — so you can see where December falls, not just the annual average.
Air quality in Johnston is worst in July — around 16 µg/m³ PM2.5 (moderate), about 1.9× the cleanest month (November, 8 µg/m³).
Modeled monthly averages (CAMS reanalysis, 2015–2024).
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| PM2.5 (µg/m³) | 10 | 13 | 14 | 14 | 15 | 15 | 16 | 14 | 12 | 10 | 8 | 10 |
| Level | Good | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate | Good | Good | Good | Good |
| PM2.5 (µg/m³) | Level | |
|---|---|---|
| Jan | 10 | Good |
| Feb | 13 | Moderate |
| Mar | 14 | Moderate |
| Apr | 14 | Moderate |
| May | 15 | Moderate |
| Jun | 15 | Moderate |
| Jul | 16 | Moderate |
| Aug | 14 | Moderate |
| Sep | 12 | Good |
| Oct | 10 | Good |
| Nov | 8 | Good |
| Dec | 10 | Good |
Where is Johnston?
Johnston sits at 41.8°N, 71.5°W, 82 ft above sea level, in United States. The nearest listed city is North Providence, 3.1 mi away.
Topography around Johnston
How much the land rises and falls, and what covers it, within 2, 10 and 50 miles of Johnston.
Within 2 miles, the terrain around Johnston has only modest variations in elevation — a maximum elevation change of 492 ft around an average of 266 ft above sea level; within 10 miles, only modest variations in elevation — a maximum elevation change of 797 ft; within 50 miles, large variations in elevation — a maximum elevation change of 2,198 ft.
The land around Johnston is covered by trees (68%) within 2 miles, trees (67%) within 10 miles, and trees (67%) and water (24%) within 50 miles.
United States travel facts
- Power plugs
- Type A / B
- 120 V · 60 Hz
- Prices
- ≈ 100% of US
- price level, 2025
- GDP per capita
- $90,027
- 2025
- Happiness
- 6.8 / 10
- World Happiness, 2025
- Safe drinking water
- 98%
- of population, 2024
- Homicide rate
- 5.8
- per 100k, 2023
- Road deaths
- 12.7
- per 100k/yr, 2019
- Income group
- High
- World Bank
- Religion
Sources: World Bank, US State Department, World Happiness Report, WHO/UNICEF, EF EPI, CIA World Factbook.
Data sources
Temperature, precipitation, cloud, humidity, wind and solar figures are a 1991–2020 climatology for Johnston (41.8219°, -71.5067°, elevation 82 ft), computed from hourly ERA5 reanalysis — contains modified Copernicus Climate Change Service information. Sun figures are astronomical calculations, not observations. City data © GeoNames, CC BY 4.0. Map outlines from Natural Earth (public domain); interactive map © Google. Tropical-cyclone seasons are the published climatological basin seasons (NOAA National Hurricane Center / regional warning centres). Sea temperatures are the NOAA OISST v2.1 1991–2020 monthly climatology (public domain), sampled at the nearest ocean point. UV index is derived from CAMS (Copernicus Atmosphere Monitoring Service) clear-sky UV data — contains modified Copernicus Atmosphere Monitoring Service information. Monthly air-quality (PM2.5) seasonality is from the CAMS EAC4 reanalysis (Copernicus Atmosphere Monitoring Service), scaled to the WHO annual mean where available. Topography is sampled from the Copernicus DEM GLO-90 elevation model (© ESA/Airbus) and ESA WorldCover 2021 land cover (CC BY 4.0).