St. Johns weather in September
In September, St. Johns sees average daytime highs of 84°F and overnight lows near 74°F, with 5.5 in of rain across 17.2 wet days and about 12.2 hours of daylight. It is the 4th-warmest and 2nd-wettest month of the year here.
Highs ease over the month, from about 86°F in the first days to 83°F by the end. The sky is clear or mostly clear about 27% of the time in September, and the air most often feels oppressive.
Daylight stretches from about 12 h 36 min at the start of September to 11 h 42 min by month's end. Set against the rest of the year, September is St. Johns's 10th-clearest and 9th-windiest month. For the whole year in context, see St. Johns's year-round climate.
- Daytime high
- 84°
- 4th warmest
- Overnight low
- 74°
- 10th coldest
- Rainfall
- 5.5 in
- 17.2 wet days
- Daylight
- 12 h 12 min
- 6:15 AM – 6:26 PM
- Cloud cover
- 63%
- 10th clearest
- Wind
- 7 mph
- 9th windiest
- Solar energy
- 4.69 kWh/m²
- Travel score
- 4.5
- out of 10
St. Johns is unincorporated community in St. Johns County, Florida, United States.
- Founded
- 2005
Air quality: WHO Ambient Air Quality Database. Density & description: Wikidata (CC0), GeoNames.
Temperature in September
Highs ease over the month, from about 86°F in the first days to 83°F by the end.
A typical September day in St. Johns reaches about 84°F in the afternoon and slips back to 74°F overnight — a 10°F spread between the day's warmth and the night's chill. On most days the high lands between 80°F and 89°F. Set against its neighbours, September runs about 3°F cooler than August and about 5°F warmer than October.
| 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 | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg high (°F) | 86 | 86 | 86 | 86 | 86 | 85 | 85 | 85 | 85 | 85 | 85 | 85 | 85 | 85 | 85 | 85 | 84 | 84 | 84 | 84 | 84 | 84 | 83 | 83 | 83 | 83 | 83 | 83 | 82 | 82 |
| Avg low (°F) | 76 | 76 | 75 | 75 | 75 | 75 | 75 | 75 | 75 | 75 | 75 | 75 | 74 | 74 | 74 | 74 | 74 | 74 | 74 | 74 | 74 | 73 | 73 | 73 | 73 | 73 | 73 | 72 | 72 | 72 |
| Avg high (°F) | Avg low (°F) | |
|---|---|---|
| 1 | 86 | 76 |
| 2 | 86 | 76 |
| 3 | 86 | 75 |
| 4 | 86 | 75 |
| 5 | 86 | 75 |
| 6 | 85 | 75 |
| 7 | 85 | 75 |
| 8 | 85 | 75 |
| 9 | 85 | 75 |
| 10 | 85 | 75 |
| 11 | 85 | 75 |
| 12 | 85 | 75 |
| 13 | 85 | 74 |
| 14 | 85 | 74 |
| 15 | 85 | 74 |
| 16 | 85 | 74 |
| 17 | 84 | 74 |
| 18 | 84 | 74 |
| 19 | 84 | 74 |
| 20 | 84 | 74 |
| 21 | 84 | 74 |
| 22 | 84 | 73 |
| 23 | 83 | 73 |
| 24 | 83 | 73 |
| 25 | 83 | 73 |
| 26 | 83 | 73 |
| 27 | 83 | 73 |
| 28 | 83 | 72 |
| 29 | 82 | 72 |
| 30 | 82 | 72 |
How September really feels in St. Johns
Once humidity and wind are folded in, September averages 19 days that feel above 90°F and 0 that feel at or below 32°F — the comfort signal a plain temperature reading hides.
The story in September is heat — humidity pushes the afternoon "feels like" well above the raw temperature.
St. Johns weather by month
How September compares with the rest of the year at a glance. September is the 4th-warmest and 2nd-wettest month here — the current month is highlighted below.
| Month | High / Low (°F) | Rainfall (inches) | Wet days | Daylight (hours) | Travel score |
|---|---|---|---|---|---|
| Jan | 65° / 49° | 2.5 | 7.7 | 10.3 | 6.4 |
| Feb | 67° / 52° | 2.5 | 6.9 | 10.9 | 6.6 |
| Mar | 72° / 56° | 2.8 | 7.3 | 11.8 | 7.2 |
| Apr | 77° / 62° | 2.1 | 6.7 | 12.7 | 7.5 |
| May | 83° / 69° | 2.5 | 8.7 | 13.5 | 6.3 |
| Jun | 86° / 74° | 5.0 | 17.6 | 13.9 | 4.0 |
| Jul | 88° / 76° | 4.8 | 20.1 | 13.7 | 3.4 |
| Aug | 87° / 76° | 5.7 | 21.2 | 13.1 | 3.4 |
| Sep | 84° / 74° | 5.5 | 17.2 | 12.2 | 4.5 |
| Oct | 79° / 67° | 3.2 | 9.8 | 11.3 | 6.8 |
| Nov | 72° / 58° | 1.7 | 6.2 | 10.5 | 7.4 |
| Dec | 67° / 53° | 2.2 | 6.7 | 10.1 | 6.7 |
Cloud cover in September
The sky is clear or mostly clear about 27% of the time in September.
Beyond those clear spells, partly cloudy skies cover about 19% of September, with mostly cloudy or overcast conditions the remaining 54%. Skies tend to open up as the month goes on.
| 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 | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Clearer (%) | 40 | 40 | 41 | 40 | 40 | 41 | 41 | 43 | 44 | 45 | 46 | 47 | 47 | 48 | 48 | 48 | 49 | 49 | 50 | 49 | 49 | 49 | 49 | 50 | 49 | 48 | 49 | 48 | 47 | 46 |
| Cloudier (%) | 60 | 60 | 59 | 60 | 60 | 59 | 59 | 57 | 56 | 55 | 54 | 53 | 53 | 52 | 52 | 52 | 51 | 51 | 50 | 51 | 51 | 51 | 51 | 50 | 51 | 52 | 51 | 52 | 53 | 54 |
| Clearer (%) | Cloudier (%) | |
|---|---|---|
| 1 | 40 | 60 |
| 2 | 40 | 60 |
| 3 | 41 | 59 |
| 4 | 40 | 60 |
| 5 | 40 | 60 |
| 6 | 41 | 59 |
| 7 | 41 | 59 |
| 8 | 43 | 57 |
| 9 | 44 | 56 |
| 10 | 45 | 55 |
| 11 | 46 | 54 |
| 12 | 47 | 53 |
| 13 | 47 | 53 |
| 14 | 48 | 52 |
| 15 | 48 | 52 |
| 16 | 48 | 52 |
| 17 | 49 | 51 |
| 18 | 49 | 51 |
| 19 | 50 | 50 |
| 20 | 49 | 51 |
| 21 | 49 | 51 |
| 22 | 49 | 51 |
| 23 | 49 | 51 |
| 24 | 50 | 50 |
| 25 | 49 | 51 |
| 26 | 48 | 52 |
| 27 | 49 | 51 |
| 28 | 48 | 52 |
| 29 | 47 | 53 |
| 30 | 46 | 54 |
Chance of precipitation in September
St. Johns gets around 5.5 in of rain over 17.2 wet days in September. The line is the day-by-day chance of measurable precipitation.
Day to day, the chance of measurable rain averages around 57% and peaks near 65% on the wettest days. The odds ease toward the end of the month.
| 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 | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Rain chance (%) | 65 | 64 | 64 | 63 | 63 | 62 | 61 | 60 | 59 | 59 | 58 | 57 | 57 | 57 | 56 | 56 | 56 | 55 | 55 | 55 | 55 | 54 | 54 | 54 | 53 | 53 | 52 | 51 | 51 | 50 |
| Rain chance (%) | |
|---|---|
| 1 | 65 |
| 2 | 64 |
| 3 | 64 |
| 4 | 63 |
| 5 | 63 |
| 6 | 62 |
| 7 | 61 |
| 8 | 60 |
| 9 | 59 |
| 10 | 59 |
| 11 | 58 |
| 12 | 57 |
| 13 | 57 |
| 14 | 57 |
| 15 | 56 |
| 16 | 56 |
| 17 | 56 |
| 18 | 55 |
| 19 | 55 |
| 20 | 55 |
| 21 | 55 |
| 22 | 54 |
| 23 | 54 |
| 24 | 54 |
| 25 | 53 |
| 26 | 53 |
| 27 | 52 |
| 28 | 51 |
| 29 | 51 |
| 30 | 50 |
Humidity in September
Most of September feels oppressive — the stacked bands show each day's mix of comfort levels, read off the dew point.
By dew point, September lands in the oppressive band about 65% of days. Sticky, muggy-or-worse air turns up on roughly 94% of them.
| 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 | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Dry (%) | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 1 | 1 | 1 | 2 | 2 | 2 | 2 |
| Comfortable (%) | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 1 | 1 | 1 | 1 | 2 | 2 | 3 | 3 | 3 | 4 | 4 |
| Humid (%) | 1 | 2 | 2 | 2 | 2 | 3 | 3 | 3 | 3 | 3 | 4 | 4 | 4 | 4 | 4 | 5 | 5 | 5 | 5 | 6 | 6 | 6 | 7 | 7 | 7 | 8 | 8 | 9 | 9 | 10 |
| Muggy (%) | 6 | 7 | 8 | 8 | 9 | 9 | 10 | 11 | 11 | 12 | 12 | 13 | 13 | 14 | 14 | 15 | 15 | 15 | 16 | 16 | 17 | 17 | 18 | 19 | 19 | 20 | 21 | 22 | 23 | 24 |
| Oppressive (%) | 66 | 65 | 66 | 67 | 67 | 68 | 68 | 68 | 69 | 69 | 68 | 68 | 69 | 68 | 68 | 67 | 67 | 68 | 66 | 66 | 65 | 66 | 64 | 63 | 63 | 61 | 59 | 58 | 56 | 54 |
| Miserable (%) | 27 | 26 | 24 | 23 | 22 | 20 | 19 | 18 | 17 | 16 | 16 | 15 | 14 | 14 | 14 | 13 | 13 | 12 | 12 | 11 | 11 | 10 | 9 | 8 | 8 | 7 | 7 | 6 | 6 | 6 |
| Dry (%) | Comfortable (%) | Humid (%) | Muggy (%) | Oppressive (%) | Miserable (%) | |
|---|---|---|---|---|---|---|
| 1 | 0 | 0 | 1 | 6 | 66 | 27 |
| 2 | 0 | 0 | 2 | 7 | 65 | 26 |
| 3 | 0 | 0 | 2 | 8 | 66 | 24 |
| 4 | 0 | 0 | 2 | 8 | 67 | 23 |
| 5 | 0 | 0 | 2 | 9 | 67 | 22 |
| 6 | 0 | 0 | 3 | 9 | 68 | 20 |
| 7 | 0 | 0 | 3 | 10 | 68 | 19 |
| 8 | 0 | 0 | 3 | 11 | 68 | 18 |
| 9 | 0 | 0 | 3 | 11 | 69 | 17 |
| 10 | 0 | 0 | 3 | 12 | 69 | 16 |
| 11 | 0 | 0 | 4 | 12 | 68 | 16 |
| 12 | 0 | 0 | 4 | 13 | 68 | 15 |
| 13 | 0 | 0 | 4 | 13 | 69 | 14 |
| 14 | 0 | 0 | 4 | 14 | 68 | 14 |
| 15 | 0 | 0 | 4 | 14 | 68 | 14 |
| 16 | 0 | 0 | 5 | 15 | 67 | 13 |
| 17 | 0 | 0 | 5 | 15 | 67 | 13 |
| 18 | 0 | 0 | 5 | 15 | 68 | 12 |
| 19 | 0 | 1 | 5 | 16 | 66 | 12 |
| 20 | 0 | 1 | 6 | 16 | 66 | 11 |
| 21 | 0 | 1 | 6 | 17 | 65 | 11 |
| 22 | 0 | 1 | 6 | 17 | 66 | 10 |
| 23 | 1 | 1 | 7 | 18 | 64 | 9 |
| 24 | 1 | 2 | 7 | 19 | 63 | 8 |
| 25 | 1 | 2 | 7 | 19 | 63 | 8 |
| 26 | 1 | 3 | 8 | 20 | 61 | 7 |
| 27 | 2 | 3 | 8 | 21 | 59 | 7 |
| 28 | 2 | 3 | 9 | 22 | 58 | 6 |
| 29 | 2 | 4 | 9 | 23 | 56 | 6 |
| 30 | 2 | 4 | 10 | 24 | 54 | 6 |
Wind in September
Winds average 7 mph in September.
Across September, daily wind ranges from about 7 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 | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Wind speed (mph) | 7 | 7 | 7 | 7 | 7 | 7 | 7 | 7 | 7 | 7 | 7 | 7 | 7 | 7 | 7 | 7 | 7 | 7 | 7 | 7 | 7 | 7 | 7 | 7 | 8 | 8 | 8 | 8 | 8 | 8 |
| Feels | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | light breeze | light breeze | light breeze | light breeze | light breeze | light breeze | light breeze |
| Wind speed (mph) | Feels | |
|---|---|---|
| 1 | 7 | calm |
| 2 | 7 | calm |
| 3 | 7 | calm |
| 4 | 7 | calm |
| 5 | 7 | calm |
| 6 | 7 | calm |
| 7 | 7 | calm |
| 8 | 7 | calm |
| 9 | 7 | calm |
| 10 | 7 | calm |
| 11 | 7 | calm |
| 12 | 7 | calm |
| 13 | 7 | calm |
| 14 | 7 | calm |
| 15 | 7 | calm |
| 16 | 7 | calm |
| 17 | 7 | calm |
| 18 | 7 | calm |
| 19 | 7 | calm |
| 20 | 7 | calm |
| 21 | 7 | calm |
| 22 | 7 | calm |
| 23 | 7 | calm |
| 24 | 7 | 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 |
Sunrise & sunset in September
Daylight runs from about 12 h 36 min at the start of September to 11 h 42 min by month's end. The lit band spans sunrise to sunset each day.
Days shrink by about 54 minutes over September. Sunrise moves from 6:07 AM to 6:23 AM, and sunset from 6:45 PM to 6:08 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 | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Daylight (h) | 12.6 | 12.6 | 12.6 | 12.5 | 12.5 | 12.5 | 12.5 | 12.4 | 12.4 | 12.4 | 12.3 | 12.3 | 12.3 | 12.2 | 12.2 | 12.2 | 12.1 | 12.1 | 12.1 | 12.1 | 12.0 | 12.0 | 12.0 | 11.9 | 11.9 | 11.9 | 11.8 | 11.8 | 11.8 | 11.7 |
| Sunrise (AM) | 6:07 | 6:07 | 6:08 | 6:08 | 6:09 | 6:10 | 6:10 | 6:11 | 6:11 | 6:12 | 6:12 | 6:13 | 6:13 | 6:14 | 6:15 | 6:15 | 6:16 | 6:16 | 6:17 | 6:17 | 6:18 | 6:19 | 6:19 | 6:20 | 6:20 | 6:21 | 6:21 | 6:22 | 6:23 | 6:23 |
| Sunset (PM) | 6:45 | 6:44 | 6:43 | 6:41 | 6:40 | 6:39 | 6:38 | 6:36 | 6:35 | 6:34 | 6:32 | 6:31 | 6:30 | 6:28 | 6:27 | 6:26 | 6:25 | 6:23 | 6:22 | 6:21 | 6:19 | 6:18 | 6:17 | 6:15 | 6:14 | 6:13 | 6:12 | 6:10 | 6:09 | 6:08 |
| Daylight (h) | Sunrise (AM) | Sunset (PM) | |
|---|---|---|---|
| 1 | 12.6 | 6:07 | 6:45 |
| 2 | 12.6 | 6:07 | 6:44 |
| 3 | 12.6 | 6:08 | 6:43 |
| 4 | 12.5 | 6:08 | 6:41 |
| 5 | 12.5 | 6:09 | 6:40 |
| 6 | 12.5 | 6:10 | 6:39 |
| 7 | 12.5 | 6:10 | 6:38 |
| 8 | 12.4 | 6:11 | 6:36 |
| 9 | 12.4 | 6:11 | 6:35 |
| 10 | 12.4 | 6:12 | 6:34 |
| 11 | 12.3 | 6:12 | 6:32 |
| 12 | 12.3 | 6:13 | 6:31 |
| 13 | 12.3 | 6:13 | 6:30 |
| 14 | 12.2 | 6:14 | 6:28 |
| 15 | 12.2 | 6:15 | 6:27 |
| 16 | 12.2 | 6:15 | 6:26 |
| 17 | 12.1 | 6:16 | 6:25 |
| 18 | 12.1 | 6:16 | 6:23 |
| 19 | 12.1 | 6:17 | 6:22 |
| 20 | 12.1 | 6:17 | 6:21 |
| 21 | 12.0 | 6:18 | 6:19 |
| 22 | 12.0 | 6:19 | 6:18 |
| 23 | 12.0 | 6:19 | 6:17 |
| 24 | 11.9 | 6:20 | 6:15 |
| 25 | 11.9 | 6:20 | 6:14 |
| 26 | 11.9 | 6:21 | 6:13 |
| 27 | 11.8 | 6:21 | 6:12 |
| 28 | 11.8 | 6:22 | 6:10 |
| 29 | 11.8 | 6:23 | 6:09 |
| 30 | 11.7 | 6:23 | 6:08 |
Solar energy in September
Average shortwave solar energy reaching the ground each day in September, about 4.69 kWh/m².
For context, solar energy here swings from a low near 2.83 kWh/m² to a high of 6.44 kWh/m² in May across the year — September's 4.69 kWh/m² falls in the middle.
| 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 | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Solar energy (kWh/m²) | 5.1 | 5.0 | 5.0 | 5.0 | 5.0 | 4.9 | 4.9 | 4.9 | 4.8 | 4.8 | 4.8 | 4.8 | 4.8 | 4.7 | 4.7 | 4.7 | 4.7 | 4.6 | 4.6 | 4.6 | 4.5 | 4.5 | 4.5 | 4.5 | 4.4 | 4.4 | 4.4 | 4.3 | 4.3 | 4.3 |
| Level | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright |
| Solar energy (kWh/m²) | Level | |
|---|---|---|
| 1 | 5.1 | Bright |
| 2 | 5.0 | Bright |
| 3 | 5.0 | Bright |
| 4 | 5.0 | Bright |
| 5 | 5.0 | Bright |
| 6 | 4.9 | Bright |
| 7 | 4.9 | Bright |
| 8 | 4.9 | Bright |
| 9 | 4.8 | Bright |
| 10 | 4.8 | Bright |
| 11 | 4.8 | Bright |
| 12 | 4.8 | Bright |
| 13 | 4.8 | Bright |
| 14 | 4.7 | Bright |
| 15 | 4.7 | Bright |
| 16 | 4.7 | Bright |
| 17 | 4.7 | Bright |
| 18 | 4.6 | Bright |
| 19 | 4.6 | Bright |
| 20 | 4.6 | Bright |
| 21 | 4.5 | Bright |
| 22 | 4.5 | Bright |
| 23 | 4.5 | Bright |
| 24 | 4.5 | Bright |
| 25 | 4.4 | Bright |
| 26 | 4.4 | Bright |
| 27 | 4.4 | Bright |
| 28 | 4.3 | Bright |
| 29 | 4.3 | Bright |
| 30 | 4.3 | Bright |
Hazard calendar for St. Johns
In September, St. Johns sits inside its atlantic hurricane and rainy season season. The full year is below, with each hazard's peak months called out.
St. Johns sits in the Atlantic hurricane belt; the season peaks August–October.
St. Johns's rainy season runs June–October, when most of the year's rain falls.
Is September a good time to visit St. Johns?
Our two travel scores rate September for general sightseeing and for beach or pool weather — 0 (poor) to 10 (ideal).
September is a reasonable time to visit St. Johns for sightseeing.
What to pack for St. Johns in September
From September's temperature range, rain chance, sun and wind — what's worth putting in the bag.
In September, St. Johns sees daytime highs around 84°F and nights near 74°F. Pack light clothes and rain gear. Worth having: sun protection. About 17 days see rain.
Sea temperature near St. Johns in September
The nearest coast averages about 82°F in September — the other half of the beach question. The full-year curve and swim-comfort zones are below.
The sea at the nearest coast (about 23 mi away) is warmest in August at about 82°F and coldest in February near 61°F.
It's comfortable for a long swim from Apr 13 to Nov 28 — about 7.6 months when the water holds above 68°F.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Sea temperature (°F) | 62 | 61 | 63 | 69 | 75 | 80 | 82 | 82 | 82 | 78 | 70 | 65 |
| Comfort | Cool | Cool | Cool | Refreshing | Refreshing | Warm | Warm | Tropical | Warm | Warm | Refreshing | Cool |
| Sea temperature (°F) | Comfort | |
|---|---|---|
| Jan | 62 | Cool |
| Feb | 61 | Cool |
| Mar | 63 | Cool |
| Apr | 69 | Refreshing |
| May | 75 | Refreshing |
| Jun | 80 | Warm |
| Jul | 82 | Warm |
| Aug | 82 | Tropical |
| Sep | 82 | Warm |
| Oct | 78 | Warm |
| Nov | 70 | Refreshing |
| Dec | 65 | Cool |
UV index in St. Johns in September
Clear-sky midday UV in September peaks around 8 (very high — sun protection essential). The full-year curve, shaded by WHO exposure level, is below.
Under clear skies, the midday UV index in St. Johns peaks around June 21 at about 11 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near December 19 at about 4 (moderate).
The index reaches 3 or more — the level where the WHO recommends sun protection — every month of the year.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| UV index (midday) | 4 | 6 | 7 | 7 | 9 | 11 | 10 | 10 | 8 | 6 | 5 | 4 |
| Level | Moderate | High | Very high | High | Very high | Extreme | Extreme | Very high | Very high | High | Moderate | Moderate |
| UV index (midday) | Level | |
|---|---|---|
| Jan | 4 | Moderate |
| Feb | 6 | High |
| Mar | 7 | Very high |
| Apr | 7 | High |
| May | 9 | Very high |
| Jun | 11 | Extreme |
| Jul | 10 | Extreme |
| Aug | 10 | Very high |
| Sep | 8 | Very high |
| Oct | 6 | High |
| Nov | 5 | Moderate |
| Dec | 4 | Moderate |
Air quality in St. Johns in September
Average fine-particle pollution (PM2.5) through the year — so you can see where September falls, not just the annual average.
Air quality in St. Johns is worst in July — around 18 µg/m³ PM2.5 (moderate), about 2.4× the cleanest month (December, 7 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) | 9 | 13 | 12 | 13 | 14 | 16 | 18 | 16 | 12 | 8 | 8 | 7 |
| Level | Good | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate | Good | Good | Good | Good |
| PM2.5 (µg/m³) | Level | |
|---|---|---|
| Jan | 9 | Good |
| Feb | 13 | Moderate |
| Mar | 12 | Moderate |
| Apr | 13 | Moderate |
| May | 14 | Moderate |
| Jun | 16 | Moderate |
| Jul | 18 | Moderate |
| Aug | 16 | Moderate |
| Sep | 12 | Good |
| Oct | 8 | Good |
| Nov | 8 | Good |
| Dec | 7 | Good |
Where is St. Johns?
St. Johns sits at 30.1°N, 81.5°W, 33 ft above sea level, in United States. The nearest listed city is Fruit Cove, 6.2 mi away.
Topography around St. Johns
How much the land rises and falls, and what covers it, within 2, 10 and 50 miles of St. Johns.
Within 2 miles, the terrain around St. Johns has only modest variations in elevation — a maximum elevation change of 118 ft around an average of 39 ft above sea level; within 10 miles, only modest variations in elevation — a maximum elevation change of 144 ft; within 50 miles, only modest variations in elevation — a maximum elevation change of 308 ft.
The land around St. Johns is covered by trees (65%) within 2 miles, trees (62%) within 10 miles, and trees (59%) and water (28%) 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 St. Johns (30.0815°, -81.5477°, elevation 33 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).