Dien Bien Phu, Vietnam

1. Fri3 PM91°6 mph
2. 4 PM89°8 mph
3. 5 PM85°6 mph
4. 6 PM82°5 mph
5. 7 PM80°2 mph
6. 8 PM79°2 mph
7. 9 PM78°2 mph
8. 10 PM77°3 mph
9. 11 PM76°3 mph
10. Sat12 AM76°3 mph
11. 1 AM76°3 mph
12. 2 AM75°2 mph
13. 3 AM75°2 mph
14. 4 AM75°2 mph
15. 5 AM74°2 mph
16. 6 AM74°2 mph
17. 7 AM76°3 mph
18. 8 AM80°4 mph
19. 9 AM83°6 mph
20. 10 AM85°7 mph
21. 11 AM87°6 mph
22. 12 PM89°6 mph
23. 1 PM90°6 mph
24. 2 PM91°6 mph
25. 3 PM90°7 mph
26. 4 PM86°9 mph
27. 5 PM84°7 mph
28. 6 PM82°4 mph
29. 7 PM80°4 mph
30. 8 PM78°5 mph
31. 9 PM78°3 mph
32. 10 PM77°3 mph
33. 11 PM76°2 mph
34. Sun12 AM76°2 mph
35. 1 AM75°2 mph
36. 2 AM72°3 mph
37. 3 AM72°4 mph
38. 4 AM72°2 mph
39. 5 AM73°3 mph
40. 6 AM73°2 mph
41. 7 AM74°2 mph
42. 8 AM74°2 mph
43. 9 AM76°2 mph
44. 10 AM79°2 mph
45. 11 AM83°3 mph
46. 12 PM85°3 mph
47. 1 PM86°4 mph
48. 2 PM86°4 mph

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

1. TodayOct 291°74°Light rain showers—0.02 inwind 8 mph
2. SatOct 391°72°Light rain—0.07 inwind 9 mph
3. SunOct 486°70°Heavy rain showers—0.53 inwind 5 mph
4. MonOct 584°69°Heavy rain—0.85 inwind 5 mph
5. TueOct 683°67°Cloudy—wind 4 mph
6. WedOct 783°67°Clear—wind 2 mph
7. ThuOct 884°66°Clear—wind 3 mph
8. FriOct 985°66°Clear—wind 3 mph
9. SatOct 1085°65°Mostly clear—wind 4 mph
10. SunOct 1183°73°Mostly clear—wind 4 mph
11. MonOct 12~77°62°Model mean
12. TueOct 13~87°66°Model mean
13. WedOct 14~85°65°Model mean
14. ThuOct 15~80°67°Model mean0.08 in
15. FriOct 16~80°67°Model mean0.20 in
16. SatOct 17~74°65°Model mean0.65 in

• Feels like93°
• WindSSW 6 mph
• Humidity52%
• Dew point71°
• Pressure29.83 inHg
• UV index4 · Moderateclear-sky peak 4 today
• Sunrise and sunsetSunrise · Sunset
• Moonrise10:22 PMMoonset 11:30 AM
• Moon phaseWaning gibbous69% 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 has no dark, clear hour without a bright moon in this forecast. Rated poor.

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

• Fri 3 PM to 7 PM 4 hours, every hour within the rules
• Sat 4 PM to 8 PM 4 hours, every hour within the rules
• Tue 1 PM to 7 PM 6 hours, every hour within the rules
• Fri 1 PM to 7 PM 6 hours, some with delta T between 8 and 10 °C
• Sat 1 PM to 7 PM 6 hours, every hour within the rules
• Sun 1 PM to 7 PM 6 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 fair.

Periods in bold fall within an hour of sunrise or sunset. The weather’s side is the fishing index · Solunar tables for Dien Bien Phu, 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 Afternoon91° · S 6–8 mph

   Light rain showers. High near 33°C. South wind 9 to 13 km/h.

2. Tonight74° · ESE 2–5 mph

   Partly cloudy. Low near 24°C. Eastsoutheast wind 3 to 8 km/h.

3. Saturday91° · SSW 2–9 mph

   Light rain. High near 33°C. Southsouthwest wind 4 to 14 km/h. Precipitation around 1.7 mm.

4. Saturday Night72° · SE 2–5 mph

   Heavy rain. Low near 22°C. Southeast wind 3 to 8 km/h. Precipitation around 4 mm.

5. Sunday86° · WSW 2–5 mph

   Heavy rain showers. High near 30°C. Westsouthwest wind 3 to 8 km/h. Precipitation around 7 mm.

6. Sunday Night70° · ENE 1–4 mph

   Heavy rain. Low near 21°C. Eastnortheast wind 2 to 7 km/h. Precipitation around 15 mm.

7. Monday84° · NE 4–5 mph

   Heavy rain. High near 29°C. Northeast wind 6 to 8 km/h. Precipitation around 9 mm.

8. Monday Night69° · E 1–2 mph

   Partly cloudy. Low near 21°C. East wind 2 to 3 km/h.

9. Tuesday83° · E 2–4 mph

   Cloudy. High near 29°C. East wind 3 to 6 km/h.

10. Tuesday Night67° · E 2 mph

    Clear. Low near 20°C. East wind around 3 km/h.

11. Wednesday83° · E 2 mph

    Clear. High near 29°C. East wind around 3 km/h.

12. Wednesday Night67° · E 1–2 mph

    Clear. Low near 19°C. East wind 2 to 3 km/h.

13. Thursday84° · E 2–3 mph

    Clear. High near 29°C. East wind 3 to 5 km/h.

14. Thursday Night66° · ENE 1–2 mph

    Clear. Low near 19°C. Eastnortheast wind 2 to 4 km/h.

15. Friday85° · E 2–3 mph

    Clear. High near 29°C. East wind 3 to 5 km/h.

16. Friday Night66° · ENE 2 mph

    Clear. Low near 19°C. Eastnortheast wind around 3 km/h.

17. Saturday85° · ENE 2–4 mph

    Mostly clear. High near 30°C. Eastnortheast wind 4 to 6 km/h.

18. Saturday Night65° · ENE 2–2 mph

    Clear. Low near 18°C. Eastnortheast wind 3 to 4 km/h.

19. Sunday83° · ENE 2–4 mph

    Mostly clear. High near 29°C. Eastnortheast wind 4 to 6 km/h.

20. Sunday Night73° · E 2 mph

    No forecast. Low near 23°C. East wind around 3 km/h.

Climate of Dien Bien Phu: 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.