São Luís de Montes Belos, Brazil

1. Sat4 PM83°8 mph
2. 5 PM82°7 mph
3. 6 PM79°3 mph
4. 7 PM77°3 mph
5. 8 PM75°5 mph
6. 9 PM74°7 mph
7. 10 PM73°7 mph
8. 11 PM72°6 mph
9. Sun12 AM71°7 mph
10. 1 AM71°6 mph
11. 2 AM70°5 mph
12. 3 AM69°5 mph
13. 4 AM69°6 mph
14. 5 AM69°7 mph
15. 6 AM69°7 mph
16. 7 AM72°8 mph
17. 8 AM77°7 mph
18. 9 AM81°9 mph
19. 10 AM85°11 mph
20. 11 AM86°11 mph
21. 12 PM87°10 mph
22. 1 PM88°13 mph
23. 2 PM76°14 mph
24. 3 PM77°4 mph
25. 4 PM80°5 mph
26. 5 PM75°11 mph
27. 6 PM73°5 mph
28. 7 PM73°6 mph
29. 8 PM72°7 mph
30. 9 PM71°7 mph
31. 10 PM72°6 mph
32. 11 PM71°3 mph
33. Mon12 AM71°4 mph
34. 1 AM71°5 mph
35. 2 AM71°5 mph
36. 3 AM71°6 mph
37. 4 AM70°6 mph
38. 5 AM70°6 mph
39. 6 AM70°6 mph
40. 7 AM71°6 mph
41. 8 AM73°4 mph
42. 9 AM75°6 mph
43. 10 AM79°9 mph
44. 11 AM82°12 mph
45. 12 PM82°12 mph
46. 1 PM82°10 mph
47. 2 PM83°10 mph
48. 3 PM82°10 mph

Scroll sideways for more hours. Pick an hour for every number.

1. TodayOct 383°69°Mostly clear—wind 8 mph
2. SunOct 488°70°Heavy rain showers—0.33 inwind 14 mph
3. MonOct 583°72°Cloudy—0.09 inwind 12 mph
4. TueOct 684°70°Rain—0.34 inwind 4 mph
5. WedOct 790°72°Light rain showers—0.07 inwind 3 mph
6. ThuOct 893°74°Mostly clear—wind 7 mph
7. FriOct 992°73°Partly cloudy—0.02 inwind 7 mph
8. SatOct 1096°73°Mostly clear—wind 9 mph
9. SunOct 1196°72°Partly cloudy—wind 9 mph
10. MonOct 1298°79°Clear—wind 7 mph
11. TueOct 13~95°74°Model mean0.03 in
12. WedOct 14~96°75°Model mean0.04 in
13. ThuOct 15~96°77°Model mean0.06 in
14. FriOct 16~94°77°Model mean
15. SatOct 17~81°73°Model mean0.21 in
16. SunOct 18~80°68°Model mean0.07 in

• Feels like85°
• WindNNW 8 mph
• Humidity56%
• Dew point66°
• Pressure29.82 inHg
• UV index2 · Lowclear-sky peak 2 today
• Sunrise and sunsetSunrise · Sunset
• Moonrise12:30 AMMoonset 11:47 AM
• Moon phaseLast quarter54% lit

Each line is one model’s own forecast at its own grid cell: three kilometers for HRRR, a quarter of a degree for the global models, which can sit a few hundred meters above or below the town. Where they agree the forecast is settled; where they part is where it is not.

NWS gridGFSGEFS ± spreadECMWFECMWF AI

A ~ marks a high or low read from six-hourly steps, which miss the true extreme by a degree or two.

ECMWF ensemble meteogram

10 daysTemperature plume

None of these is a measurement. Each is a rating of the forecast ahead, and of what is happening at the point right now, against what the activity or the ailment is known to mind, and each names the figure that decided it. An ailment or a pest is rated as a risk, low to extreme; an activity, a chore or a journey as a condition, poor to ideal.

Each rating says which span it is for: the rest of today’s daylight, tonight, or the next 24 hours.

Tonight: 5 dark, clear hours without a bright moon, from 8:00 PM. Rated good.

The last night runs past the end of the forecast and is rated on the hours it covers.

Dark is the sun 18 degrees below the horizon; where it never gets that low, 12 degrees, marked nautical. Clear is sky cover of 20% or less. A bright moon is one above the horizon with a quarter or more of its disc lit. Transparency in the table is estimated from surface humidity (70% and 85% mark fair and poor) and visibility, since the forecast carries no haze or high cloud moisture. Seeing and transparency by hour, where shown, are Environment and Climate Change Canada’s astronomy forecast (regional model; seeing from cloud, wind shear, turbulence near the ground and the surface temperature trend; transparency from the moisture through the whole air column), under the Open Government Licence - Canada. Dew is the air within 2 °C of its dew point. Excellent is four or more clear moonless hours with good transparency; good is three; fair is one, or two clear hours.

Golden hour is the sun between 6 degrees above the horizon and 4 degrees below it; blue hour is the sun between 4 and 6 degrees below. These are the definitions timeanddate.com and PhotoPills use. Directions are degrees clockwise from true north, where the sun’s upper edge and the moon’s center cross a flat horizon; hills and buildings change both. None means the sun does not reach that height on the day; all day means it stays inside the band.

Hours fit for spraying, and the days dry enough for fieldwork and hay, read from this forecast’s wind, gusts, humidity, temperature and rain.

Spraying windows

• Sat 4 PM to 7 PM 3 hours, every hour within the rules
• Sat 8 PM to Sun 1 AM 5 hours, every hour within the rules
• Sun 7 AM to 9 AM 2 hours, every hour within the rules
• Mon 9 AM to 11 AM 2 hours, every hour within the rules
• Mon 3 PM to 7 PM 4 hours, every hour within the rules
• Wed 3 PM to 9 PM 6 hours, some with delta T between 8 and 10 °C
• Thu 9 AM to 3 PM 6 hours, every hour within the rules
• Fri 3 AM to 3 PM 12 hours, every hour within the rules

Good Marginal No

Field days

Spraying: sustained wind 3 to 10 mph, the range US extension services and most labels give; gusts no more than 15 mph (this page’s limit); delta T (air minus wet-bulb temperature) 2 to 8 °C preferred and 8 to 10 °C marginal, from GRDC guidance, with the wet bulb by Stull’s formula; no hour at a 30% chance of rain or 0.25 mm forecast during the rain-free time. Follow the product label, which overrides all of this. Field days: dry is no daytime hour at a 30% chance and under 1 mm all day, wet is 6 mm (0.25 in) or more; soil moisture is not in the forecast, so ground still wet from earlier rain is not accounted for. Hay drying marks a dry day with humidity down to 50% and a breeze of 5 mph or more.

The best-rated day this week is Friday, rated best.

Periods in bold fall within an hour of sunrise or sunset. The weather’s side is the fishing index · Solunar tables for São Luís de Montes Belos, by month

Major periods are two hours centered on the moon’s passage overhead and underfoot; minor periods are one hour centered on moonrise and moonset: the conventional durations of John Alden Knight’s solunar tables (1936). The rating is this site’s: one point to start, two more within a day and a half of a new or full moon (one more within three and a half days), and one more when a period falls within an hour of sunrise or sunset. The theory has mixed support in fisheries research; the times are exact astronomy.

1. This Afternoon83° · NNW 7 mph

   Mostly clear. High near 28°C. Northnorthwest wind around 12 km/h.

2. Tonight69° · NE 3–7 mph

   Mostly clear. Low near 21°C. Northeast wind 5 to 12 km/h.

3. Sunday88° · NNW 4–14 mph

   Heavy rain showers. High near 31°C. Northnorthwest wind 6 to 23 km/h. Precipitation around 8 mm.

4. Sunday Night70° · NE 2–7 mph

   Heavy rain. Low near 21°C. Northeast wind 4 to 12 km/h. Precipitation around 3 mm.

5. Monday83° · NNW 4–12 mph

   Cloudy. High near 29°C. Northnorthwest wind 6 to 19 km/h.

6. Monday Night72° · ESE 1–3 mph

   Rain. Low near 22°C. Eastsoutheast wind 2 to 5 km/h. Precipitation around 1.2 mm.

7. Tuesday84° · NNE 3–4 mph

   Rain. High near 29°C. Northnortheast wind 5 to 6 km/h. Precipitation around 6 mm.

8. Tuesday Night70° · E 2–3 mph

   Rain. Low near 21°C. East wind 4 to 5 km/h. Precipitation around 2 mm.

9. Wednesday90° · SW 2–3 mph

   Light rain showers. High near 32°C. Southwest wind 4 to 5 km/h. Precipitation around 0.8 mm.

10. Wednesday Night72° · ESE 3 mph

    Mostly clear. Low near 22°C. Eastsoutheast wind around 5 km/h.

11. Thursday93° · NE 3–7 mph

    Mostly clear. High near 34°C. Northeast wind 5 to 12 km/h.

12. Thursday Night74° · ESE 2–5 mph

    Mostly clear. Low near 23°C. Eastsoutheast wind 4 to 8 km/h.

13. Friday92° · ENE 5–7 mph

    Partly cloudy. High near 33°C. Eastnortheast wind 8 to 11 km/h.

14. Friday Night73° · SE 3–4 mph

    Clear. Low near 23°C. Southeast wind 5 to 6 km/h.

15. Saturday96° · SSW 2–5 mph

    Mostly clear. High near 36°C. Southsouthwest wind 4 to 8 km/h.

16. Saturday Night73° · SSE 8–9 mph

    Partly cloudy. Low near 23°C. Southsoutheast wind 13 to 15 km/h.

17. Sunday96° · SSE 5 mph

    Partly cloudy. High near 36°C. Southsoutheast wind around 8 km/h.

18. Sunday Night72° · ESE 2–6 mph

    Clear. Low near 22°C. Eastsoutheast wind 4 to 9 km/h.

19. Monday98° · SW 1–7 mph

    Clear. High near 37°C. Southwest wind 2 to 11 km/h.

20. Monday Night79° · ESE 3 mph

    No forecast. Low near 26°C. Eastsoutheast wind around 5 km/h.

Climate of São Luís de Montes Belos: normals, records and every month

The forecast office edits about sixty fields for every cell of its grid. The common ones are above; these are the rest, as the daily extreme, for anyone who needs the mixing height, the fire danger or the swell.