Weis Farm observing site
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Weis Farm observing site clear sky chart from 2005-11-06 to 2024-01-14.

This page is a summary of past forecasts. Even though it's based only on forecasts, some people use these pages as clue to a site's climate. But climate data based on actual observation should be preferred (if you can find it!).

Cloud, Transparency and Seeing forecasts are summarized individually. But because good observing conditions require a combination of minimum cloud cover, transparency and seeing, the individual forecast summaries can be difficult to interpret. The observing conditions section counts the combinations of conditions needed for common types of astronomical observation.

Observing Conditions

The following tables count the occurrence of the combinations of forecast and darkness conditions needed for different observations. Conditions are rated by by what percentage of the hours the observation would likely be attempted are usable.
Observation TypeMinimum conditions for hour to be usableOut of hours
Clear of CloudsTransparencySeeingSky Brightness
Planetary:50%(no limit)Average(no limit)Nighttime Hours
Deep Sky:70%Average(no limit)5.9Nighttime Hours
CCD Imaging:70%Below AveragePoor(no limit)Nighttime Hours

Percentages are of nighttime hours per month, or per year, when a particular observing conditions was met. Deep Sky percentages never exceed 50% because the moon is up half the time. Deep sky percentages are much lower for charts at high latitudes because of fewer dark hours in the summer.

Overall

PlanetaryData
Pts
Deep Sky
Max 60%
Data
Pts
Both Planetary and Deep Sky
Max 60%
Data
Pts
Either Planetary or Deep SkyData
Pts
CCD ImagingData
Pts
Night
46%
24368
30%
74169
17%
24314
58%
24314
42%
38881

By Month

MonthDays of MonthPlanetaryData
Pts
Deep Sky
Max 60%
Data
Pts
Both Planetary and Deep Sky
Max 60%
Data
Pts
Either Planetary or Deep SkyData
Pts
CCD ImagingData
Pts
January1st to 10thNight
45%
950
30%
2647
14%
946
57%
946
45%
1418
January11th to 20thNight
46%
918
33%
2515
17%
918
57%
918
47%
1338
January21st to endNight
45%
895
36%
2479
18%
895
57%
895
46%
1324
February1st to 10thNight
41%
720
30%
2160
16%
720
53%
720
38%
1170
February11th to 20thNight
29%
703
26%
2098
11%
700
43%
700
33%
1202
February21st to endNight
30%
592
37%
1776
13%
592
50%
592
44%
900
March1st to 10thNight
36%
720
30%
2160
13%
720
51%
720
41%
1131
March11th to 20thNight
38%
611
28%
2051
16%
611
52%
611
39%
1037
March21st to endNight
24%
594
29%
2099
11%
594
47%
594
32%
1092
April1st to 10thNight
31%
540
30%
1800
13%
540
52%
540
40%
883
April11th to 20thNight
24%
533
27%
1777
9%
533
48%
533
33%
940
April21st to endNight
31%
540
24%
1719
12%
540
49%
540
34%
938
May1st to 10thNight
32%
540
26%
1620
15%
540
50%
540
36%
927
May11th to 20thNight
42%
531
22%
1593
14%
531
54%
531
38%
890
May21st to endNight
34%
582
20%
1745
8%
582
49%
582
34%
1021
June1st to 10thNight
46%
540
21%
1580
11%
540
57%
540
42%
859
June11th to 20thNight
39%
540
25%
1440
9%
540
53%
540
43%
813
June21st to endNight
50%
540
25%
1440
14%
540
59%
540
47%
799
July1st to 10thNight
65%
525
23%
1400
18%
525
69%
525
44%
814
July11th to 20thNight
72%
522
26%
1422
22%
522
75%
522
51%
748
July21st to endNight
66%
591
22%
1673
21%
558
69%
558
37%
973
August1st to 10thNight
69%
537
20%
1636
20%
534
72%
534
36%
947
August11th to 20thNight
62%
534
24%
1778
27%
534
67%
534
34%
992
August21st to endNight
65%
594
27%
1980
27%
594
72%
594
43%
999
September1st to 10thNight
60%
540
29%
1821
25%
540
70%
540
43%
899
September11th to 20thNight
48%
540
31%
1980
23%
540
64%
540
40%
961
September21st to endNight
54%
540
36%
1980
29%
540
67%
540
45%
896
October1st to 10thNight
49%
540
34%
1980
26%
540
62%
540
38%
982
October11th to 20thNight
48%
566
41%
2006
24%
566
66%
566
50%
846
October21st to endNight
49%
990
34%
2574
15%
990
58%
990
53%
1353
November1st to 10thNight
54%
925
35%
2405
14%
925
64%
925
61%
1198
November11th to 20thNight
48%
950
40%
2470
16%
950
61%
950
61%
1219
November21st to endNight
50%
950
35%
2470
17%
950
61%
950
48%
1334
December1st to 10thNight
47%
950
35%
2470
16%
950
59%
950
47%
1376
December11th to 20thNight
42%
948
36%
2869
16%
948
55%
948
43%
1481
December21st to endNight
39%
1037
23%
4556
15%
1026
52%
1026
29%
2181

Individual Forecasts

The length of each colored bar in the "occurrence of each Forecast" column is proportional to the number of times the chart forecast that color. The percentages are of the total number of hours per month, or per year, with a particular forecast. The colors as the same as those used in clear sky charts.

Note: Transparency probabilities are only counted for those hours that have 30% or less cloud cover. Seeing probabilities are only counted for those hours that have 80% or less cloud cover. If that's too tricky, try Observing Conditions instead.

Overall

Occurrence of each ForecastData
Points
Cloud CoverDay
6%42432345%7%60%
75048
Night
6%42442445%7%59%
74704
TransparencyDay
24%5%10%24%26%11%
74765
Night
24%5%10%24%25%12%
74510
SeeingDay
7%6%27%34%21%5%
14304
Night
7%7%36%38%11%
24381

By Month

Percentage Cloud Cover SW (2006-)
Color Meanings:
Overcast 90% covered 80% covered 70% covered 60% covered 50% covered 40% covered 30% covered 20% covered 10% covered Clear
MonthDays in MonthOccurrence of each ForecastData
Points
January1st to 10thDay
442432335%6%64%
1518
11th to 20thDay
5%5%24424245%62%
1512
21st to endDay
4424333347%62%
1894
February1st to 10thDay
6%7%26%324245%58%
1800
11th to 20thDay
47%36%5%23347%56%
1749
21st to endDay
5%5%24423446%63%
1480
March1st to 10thDay
5%6%24424447%59%
1800
11th to 20thDay
10%41332335%6%59%
1908
21st to endDay
8%5%1442335%7%57%
2254
April1st to 10thDay
7%31332335%6%65%
2160
11th to 20thDay
10%42332345%7%58%
2131
21st to endDay
9%5%2432345%8%55%
2240
May1st to 10thDay
9%41342445%7%57%
2340
11th to 20thDay
8%42332445%8%56%
2302
21st to endDay
6%3244245%6%9%55%
2531
June1st to 10thDay
43145%2446%9%58%
2374
11th to 20thDay
5%2133235%5%8%63%
2520
21st to endDay
33233345%6%9%60%
2520
July1st to 10thDay
5%2144246%6%10%54%
2520
11th to 20thDay
3212425%46%9%62%
2487
21st to endDay
5%2244345%7%10%55%
2546
August1st to 10thDay
4214425%6%6%11%55%
2289
11th to 20thDay
6%42343446%8%55%
2123
21st to endDay
431332446%9%60%
2376
September1st to 10thDay
8%424323346%59%
2138
11th to 20thDay
6%41442445%6%61%
1980
21st to endDay
4213322445%68%
1980
October1st to 10thDay
11%424423346%59%
1980
11th to 20thDay
6%312212335%72%
1932
21st to endDay
8%423222245%67%
1782
November1st to 10thDay
4412312335%70%
1673
11th to 20thDay
3413313336%70%
1710
21st to endDay
7%42332334464%
1710
December1st to 10thDay
36%34323447%61%
1710
11th to 20thDay
7%42322345%6%62%
2161
21st to endDay
5%7%37%6%3445%6%51%
2918
January1st to 10thNight
342442445%6%61%
2647
11th to 20thNight
5%5%24323346%63%
2515
21st to endNight
45%23433347%62%
2479
February1st to 10thNight
46%35%434345%60%
2160
11th to 20thNight
5%5%36%5%35%45%6%53%
2098
21st to endNight
6%5%24323446%62%
1776
March1st to 10thNight
5%5%243235%5%7%58%
2160
11th to 20thNight
8%5%24323447%60%
2051
21st to endNight
8%5%233245%5%8%55%
2099
April1st to 10thNight
6%32432445%7%61%
1800
11th to 20thNight
8%5%3432345%8%55%
1777
21st to endNight
11%42332445%8%53%
1719
May1st to 10thNight
9%5%244245%5%7%54%
1620
11th to 20thNight
9%4134235%7%8%54%
1593
21st to endNight
8%424435%5%5%9%52%
1745
June1st to 10thNight
4313335%5%7%11%55%
1580
11th to 20thNight
4313435%6%7%8%58%
1440
21st to endNight
431443448%10%55%
1440
July1st to 10thNight
6%323325%6%6%12%52%
1440
11th to 20thNight
22134345%6%11%59%
1470
21st to endNight
5%425%5%35%5%7%11%47%
1772
August1st to 10thNight
5%3135%47%7%8%11%46%
1646
11th to 20thNight
7%425%5%35%5%6%9%50%
1778
21st to endNight
5%2144335%5%10%58%
1980
September1st to 10thNight
7%314324347%62%
1821
11th to 20thNight
6%41342347%6%59%
1980
21st to endNight
5%213324346%66%
1980
October1st to 10thNight
10%423213346%62%
1980
11th to 20thNight
6%21221233473%
2006
21st to endNight
7%413222245%68%
2574
November1st to 10thNight
3212312347%70%
2405
11th to 20thNight
2212323336%72%
2470
21st to endNight
7%423313346%64%
2470
December1st to 10thNight
442442335%8%61%
2470
11th to 20thNight
6%414423347%62%
3036
21st to endNight
45%244345%5%8%55%
4727

Transparency (when cloud cover <= 30%)
Color Meanings:
Too cloudy to forecast Poor Below Average Average Above average Transparent
MonthDays in MonthOccurrence of each ForecastData
Points
January1st to 10thDay
22%49%29%29%7%
1519
11th to 20thDay
25%48%25%29%9%
1512
21st to endDay
23%39%29%28%8%
1894
February1st to 10thDay
30%311%24%24%9%
1800
11th to 20thDay
30%48%26%21%12%
1759
21st to endDay
24%26%22%30%16%
1480
March1st to 10thDay
26%38%21%25%16%
1800
11th to 20thDay
26%410%22%27%12%
1908
21st to endDay
27%5%12%26%22%8%
2254
April1st to 10thDay
22%39%24%27%16%
2160
11th to 20thDay
27%410%23%23%12%
2134
21st to endDay
28%411%23%26%9%
2240
May1st to 10thDay
28%410%25%22%12%
2340
11th to 20thDay
26%6%15%27%20%5%
2306
21st to endDay
25%8%16%22%20%10%
2531
June1st to 10thDay
22%7%15%26%21%9%
2374
11th to 20thDay
19%6%10%20%27%17%
2520
21st to endDay
18%6%12%27%26%12%
2520
July1st to 10thDay
25%8%12%25%24%7%
2451
11th to 20thDay
18%6%11%26%30%9%
2412
21st to endDay
24%7%15%30%21%2
2405
August1st to 10thDay
21%8%17%30%18%6%
2275
11th to 20thDay
26%7%11%26%21%9%
2123
21st to endDay
21%6%12%26%25%10%
2376
September1st to 10thDay
27%5%9%22%25%13%
2138
11th to 20thDay
24%5%8%21%28%14%
1980
21st to endDay
19%49%25%29%14%
1980
October1st to 10thDay
28%49%19%28%12%
1980
11th to 20thDay
17%27%20%33%21%
1932
21st to endDay
22%38%21%33%14%
1782
November1st to 10thDay
18%38%21%35%15%
1673
11th to 20thDay
18%35%28%34%12%
1710
21st to endDay
23%36%20%31%16%
1710
December1st to 10thDay
23%410%30%25%8%
1710
11th to 20thDay
23%48%26%30%10%
2159
21st to endDay
33%5%8%19%26%9%
2918
January1st to 10thNight
24%410%26%28%8%
2647
11th to 20thNight
24%38%25%30%12%
2515
21st to endNight
24%37%28%29%9%
2479
February1st to 10thNight
27%410%22%27%10%
2160
11th to 20thNight
32%49%21%23%10%
2098
21st to endNight
24%36%20%30%18%
1776
March1st to 10thNight
26%38%22%28%14%
2160
11th to 20thNight
25%49%24%22%16%
2051
21st to endNight
26%7%11%25%20%10%
2099
April1st to 10thNight
24%39%22%25%17%
1800
11th to 20thNight
27%6%11%23%23%11%
1777
21st to endNight
30%413%23%21%8%
1719
May1st to 10thNight
29%5%11%21%21%12%
1620
11th to 20thNight
26%7%17%21%22%7%
1594
21st to endNight
29%9%15%22%16%10%
1746
June1st to 10thNight
21%9%19%28%16%8%
1580
11th to 20thNight
21%9%12%21%24%12%
1440
21st to endNight
22%6%14%26%20%12%
1440
July1st to 10thNight
24%8%14%26%22%6%
1400
11th to 20thNight
18%7%14%25%25%10%
1422
21st to endNight
28%9%15%27%19%3
1673
August1st to 10thNight
27%10%19%24%16%6%
1636
11th to 20thNight
30%6%12%28%16%8%
1778
21st to endNight
23%6%13%25%25%9%
1980
September1st to 10thNight
23%5%13%22%24%14%
1821
11th to 20thNight
23%6%11%20%26%14%
1980
21st to endNight
19%5%7%24%29%16%
1980
October1st to 10thNight
25%5%9%19%27%15%
1980
11th to 20thNight
18%26%17%32%24%
2006
21st to endNight
20%36%24%29%18%
2574
November1st to 10thNight
15%39%22%29%21%
2405
11th to 20thNight
14%37%25%36%15%
2470
21st to endNight
22%36%21%29%18%
2470
December1st to 10thNight
23%49%28%26%10%
2470
11th to 20thNight
23%37%26%32%9%
3037
21st to endNight
26%5%10%25%25%8%
4727

Seeing (when cloud cover <= 80%)
Color Meanings:
Too cloudy to forecast Bad 1/5 Poor 2/5 Average 3/5 Good 4/5 Excellent 5/5
MonthDays in MonthOccurrence of each ForecastData
Points
January1st to 10thDay
7%6%35%39%11%2
270
11th to 20thDay
10%11%30%32%14%2
249
21st to endDay
39%39%34%13%1
264
February1st to 10thDay
7%9%43%35%6%
240
11th to 20thDay
10%9%43%26%10%3
240
21st to endDay
5%7%55%30%3
198
March1st to 10thDay
7%9%43%29%13%
240
11th to 20thDay
14%10%35%26%14%2
240
21st to endDay
14%12%34%28%12%1
340
April1st to 10thDay
9%12%41%25%11%2
420
11th to 20thDay
12%14%38%29%6%1
412
21st to endDay
15%14%38%23%9%2
500
May1st to 10thDay
10%8%36%32%12%2
603
11th to 20thDay
12%8%28%32%16%4
625
21st to endDay
8%8%33%32%17%1
679
June1st to 10thDay
5%423%36%24%7%
630
11th to 20thDay
46%29%36%22%4
630
21st to endDay
3323%44%23%4
630
July1st to 10thDay
5%114%37%34%9%
621
11th to 20thDay
3111%39%37%9%
618
21st to endDay
5%19%38%37%9%
684
August1st to 10thDay
4111%39%37%8%
587
11th to 20thDay
3118%38%33%6%
437
21st to endDay
4113%41%31%9%
495
September1st to 10thDay
8%216%37%29%7%
428
11th to 20thDay
3215%39%30%11%
270
21st to endDay
7%323%36%24%7%
270
October1st to 10thDay
12%7%22%31%19%9%
270
11th to 20thDay
5%433%34%18%7%
270
21st to endDay
16%7%26%28%18%5%
297
November1st to 10thDay
6%6%32%32%19%4
270
11th to 20thDay
6%9%33%33%18%1
270
21st to endDay
14%10%26%30%16%6%
270
December1st to 10thDay
4436%38%15%3
270
11th to 20thDay
10%7%34%32%17%1
270
21st to endDay
11%15%35%30%8%
297
January1st to 10thNight
6%9%35%41%9%1
950
11th to 20thNight
9%8%33%38%12%1
918
21st to endNight
7%7%37%40%8%1
895
February1st to 10thNight
8%9%38%38%7%
720
11th to 20thNight
8%10%49%29%5%
704
21st to endNight
10%9%49%28%4
592
March1st to 10thNight
8%10%42%34%5%
720
11th to 20thNight
9%10%41%30%9%
611
21st to endNight
11%14%49%24%3
594
April1st to 10thNight
9%9%47%30%3
540
11th to 20thNight
11%13%50%22%3
533
21st to endNight
11%10%46%25%7%1
540
May1st to 10thNight
10%10%44%30%6%
540
11th to 20thNight
8%8%40%34%9%1
531
21st to endNight
8%9%45%30%7%
584
June1st to 10thNight
46%40%39%12%
540
11th to 20thNight
46%48%35%6%
540
21st to endNight
4436%46%9%
540
July1st to 10thNight
5%221%52%19%1
525
11th to 20thNight
3219%52%23%
522
21st to endNight
6%117%53%23%1
591
August1st to 10thNight
4218%50%25%
537
11th to 20thNight
10%121%50%18%
534
21st to endNight
5%122%49%22%1
594
September1st to 10thNight
8%126%50%15%
540
11th to 20thNight
7%238%41%10%2
540
21st to endNight
6%5%33%41%15%
540
October1st to 10thNight
12%6%31%40%11%
540
11th to 20thNight
7%7%36%38%11%1
566
21st to endNight
9%8%32%34%15%1
990
November1st to 10thNight
5%5%33%46%11%1
925
11th to 20thNight
48%39%39%10%1
950
21st to endNight
8%10%30%38%14%1
950
December1st to 10thNight
5%8%37%41%9%
950
11th to 20thNight
9%8%37%37%9%
950
21st to endNight
10%11%37%35%7%
1045
Page generated at 2024-01-11 03:22:38. Version ac07

Copyright 2024 Attilla Danko


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