40.0240, -75.8130

1. Sun4 AM56°1%6 mph
2. 5 AM56°2%6 mph
3. 6 AM55°3%6 mph
4. 7 AM56°4%7 mph
5. 8 AM58°17%7 mph
6. 9 AM58°30%7 mph
7. 10 AM59°43%8 mph
8. 11 AM59°42%8 mph
9. 12 PM60°40%8 mph
10. 1 PM61°39%8 mph
11. 2 PM61°35%8 mph
12. 3 PM61°31%7 mph
13. 4 PM61°27%7 mph
14. 5 PM61°22%6 mph
15. 6 PM60°18%6 mph
16. 7 PM59°14%5 mph
17. 8 PM59°8%5 mph
18. 9 PM59°8%2 mph
19. 10 PM59°8%2 mph
20. 11 PM59°8%1 mph
21. Mon12 AM59°8%1 mph
22. 1 AM58°8%0 mph
23. 2 AM58°0 mph
24. 3 AM58°1 mph
25. 4 AM58°2 mph
26. 5 AM57°3 mph
27. 6 AM57°5 mph
28. 7 AM57°5 mph
29. 8 AM56°6 mph
30. 9 AM58°8 mph
31. 10 AM60°9 mph
32. 11 AM62°10 mph
33. 12 PM64°12 mph
34. 1 PM65°12 mph
35. 2 PM66°12 mph
36. 3 PM67°12 mph
37. 4 PM65°12 mph
38. 5 PM65°9 mph
39. 6 PM63°7 mph
40. 7 PM59°6 mph
41. 8 PM56°5 mph
42. 9 PM54°5 mph
43. 10 PM53°5 mph
44. 11 PM52°5 mph
45. Tue12 AM51°5 mph
46. 1 AM49°5 mph
47. 2 AM48°5 mph
48. 3 AM47°5 mph

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

1. TodayOct 463°55°Chance Rain Showers43%0.08 inwind 8 mph · gusts 16 mph
2. MonOct 567°43°Mostly Sunny8%wind 12 mph · gusts 23 mph
3. TueOct 662°43°Sunny0%wind 5 mph · gusts 10 mph
4. WedOct 767°50°Sunny1%wind 9 mph · gusts 18 mph
5. ThuOct 871°50°Sunny1%wind 7 mph · gusts 15 mph
6. FriOct 969°51°Sunny0%wind 7 mph · gusts 15 mph
7. SatOct 1067°49°Mostly Sunny4%wind 6 mph · gusts 12 mph
8. SunOct 1166°52°35%wind 6 mph · gusts 13 mph

• Feels like56°
• WindENE 6 mphgusts 12 mph
• Radar over this pointno reading
• Humidity90%
• Dew point53°
• Pressure—
• UV index—
• Air quality—
• Visibility10 mi
• Sunrise and sunsetSunrise · Sunset · not yet up
• Moonrise12:02 AMMoonset 3:35 PM
• Moon phaseLast quarter43% lit

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.

This hour: fly with caution (gusts near or over your limit, night: lighting and night training required (107.29)). Next good stretch: Mon 8 AM to 10 AM, 2 hours.

Today: civil twilight for Part 107 6:33 AM to sunrise 7:03 AM, and sunset 6:41 PM to 7:11 PM. Anti-collision lighting is required in those minutes and at night.

Good Caution No-fly

Flight restrictions nearby

Reading the FAA’s temporary flight restrictions.

Flight restrictions on the map. TFRs are not the whole picture: controlled airspace around airports needs LAANC authorization. Check the FAA’s B4UFLY.

Wind at 400 ft is estimated from the 10 m forecast by the power law, with exponents for each Pasquill stability class (Irwin 1979, rural, as in EPA dispersion models; the class from wind, sun height and cloud, after Turner 1970); gusts keep the ground gust’s margin. Caution from three quarters of your limit; the default 24 mph is the wind resistance printed for common sub-250 g drones. 14 CFR 107.51: “The minimum flight visibility, as observed from the location of the control station must be no less than 3 statute miles” and at least “500 feet below the cloud”. 14 CFR 107.29: “No person may operate a small unmanned aircraft system during periods of civil twilight unless the small unmanned aircraft has lighted anti-collision lighting visible for at least 3 statute miles”; civil twilight is the 30 minutes before sunrise and after sunset, in Alaska the Air Almanac’s. Kp: SWPC’s scales say satellite navigation problems may occur at G3 (Kp 7) and navigation is “degraded for hours” at G4 (Kp 8); Kp 5 is the typical app warning. Typical limits, not rules: rain chance 30% caution and 60% no-fly, thunder 10% and 20%, below 0 °C caution and −10 °C no-fly, over 40 °C caution. Your drone’s manual and the airspace come first.

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

• Mon 6 PM to Tue 7 AM 13 hours, every hour within the rules
• Tue 8 AM to 7 PM 11 hours, every hour within the rules
• Wed 6 PM to 9 PM 3 hours, every hour within the rules
• Thu 10 AM to 10 PM 12 hours, every hour within the rules
• Fri 9 AM to Sat 8 AM 23 hours, every hour within the rules
• Sat 9 AM to 7 PM 10 hours, every hour within the rules
• Sun 10 AM to 4 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 best.

Periods in bold fall within an hour of sunrise or sunset. The weather’s side is the fishing index

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. Overnight54° · 2% · NE 5 mph

   Mostly cloudy, with a low around 54. Northeast wind around 5 mph. New rainfall amounts less than a tenth of an inch possible.

2. Sunday63° · 43% · E 5–10 mph

   A chance of rain showers after 8am. Cloudy, with a high near 63. East wind 5 to 10 mph. Chance of precipitation is 40%. New rainfall amounts less than a tenth of an inch possible.

3. Sunday Night55° · 18% · N 0–5 mph

   A slight chance of rain showers before 7pm, then patchy fog between 11pm and 5am. Cloudy, with a low around 55. North wind 0 to 5 mph. Chance of precipitation is 20%.

4. Monday67° · NW 5–10 mph

   Mostly sunny, with a high near 67. Northwest wind 5 to 10 mph, with gusts as high as 25 mph.

5. Monday Night43° · NW 5 mph

   Clear, with a low around 43. Northwest wind around 5 mph.

6. Tuesday62° · NW 5 mph

   Sunny, with a high near 62.

7. Tuesday Night43° · SW 0–5 mph

   Clear, with a low around 43.

8. Wednesday67° · 1% · S 0–10 mph

   Sunny, with a high near 67.

9. Wednesday Night50° · 1% · SW 5 mph

   Mostly clear, with a low around 50.

10. Thursday71° · 1% · W 5 mph

    Sunny, with a high near 71.

11. Thursday Night50° · 1% · W 0–5 mph

    Mostly clear, with a low around 50.

12. Friday69° · W 0–5 mph

    Sunny, with a high near 69.

13. Friday Night51° · W 5 mph

    Partly cloudy, with a low around 51.

14. Saturday67° · 2% · NW 5 mph

    Mostly sunny, with a high near 67.

Written by the forecaster on duty for their own colleagues and for anyone who wants to know why the forecast says what it says. It is not edited for the public, so it uses the office’s shorthand; it is also the most honest thing any weather service publishes.

Fetching the discussion…

The national centers each publish a judgment the local grid does not carry. Read here at this exact coordinate.

Reading the outlooks…

The last spring freeze (32°F) usually comes around April 19 and the first fall freeze around October 25: a growing season of about 190 days.

One fall in ten brings a freeze by October 11; one spring in ten still has one after May 4.

Climate of 40.02, -75.81: 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.

Each forecast day against the same calendar date at the nearest long-record station: the 1991 to 2020 normal, and the record high and low with the year they were set.

Reading the station’s record…