Teterville
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Teterville clear sky chart from 2005-11-05 to 2017-12-02.

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
42%
16171
25%
47831
14%
16124
52%
16124
34%
27348

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 15thNight
32%
900
28%
2327
10%
895
44%
895
36%
1390
January16th to endNight
30%
960
31%
2496
10%
960
44%
960
38%
1448
February1st to 15thNight
26%
875
20%
2283
6%
871
35%
871
29%
1475
February16th to endNight
30%
632
28%
1894
9%
632
44%
632
33%
1066
March1st to 15thNight
34%
546
23%
1986
14%
546
46%
546
27%
1103
March16th to endNight
27%
576
18%
2112
11%
576
38%
576
21%
1295
April1st to 15thNight
28%
539
22%
1911
11%
539
44%
539
28%
1028
April16th to endNight
30%
540
21%
1641
13%
540
42%
540
28%
1001
May1st to 15thNight
37%
540
20%
1620
14%
540
47%
540
28%
1005
May16th to endNight
47%
563
19%
1684
15%
561
53%
561
31%
1010
June1st to 15thNight
52%
540
17%
1620
10%
540
59%
540
40%
901
June16th to endNight
58%
540
22%
1620
14%
540
65%
540
48%
822
July1st to 15thNight
69%
510
20%
1530
16%
510
72%
510
43%
817
July16th to endNight
75%
564
24%
1594
25%
531
77%
531
41%
867
August1st to 15thNight
74%
539
23%
1610
27%
536
77%
536
42%
868
August16th to endNight
70%
573
27%
1767
29%
573
74%
573
41%
951
September1st to 15thNight
59%
540
23%
1951
23%
540
65%
540
32%
1054
September16th to endNight
57%
537
32%
1980
28%
537
66%
537
35%
988
October1st to 15thNight
45%
660
28%
2100
20%
660
52%
660
31%
1203
October16th to endNight
40%
768
33%
2304
15%
768
54%
768
42%
1168
November1st to 15thNight
39%
884
30%
2404
12%
884
51%
884
41%
1338
November16th to endNight
35%
975
31%
2535
11%
975
48%
975
39%
1474
December1st to 15thNight
31%
910
25%
2366
9%
910
43%
910
33%
1483
December16th to endNight
34%
960
27%
2496
11%
960
45%
960
31%
1593

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
9%5%14323346%56%
48620
Night
8%413323345%60%
48027
Cloud CoverDay
11%5%24424447%47%
48618
Night
9%424323347%52%
48027
TransparencyDay
35%312%27%16%3
48318
Night
31%312%27%19%4
47832
SeeingDay
12%7%26%30%18%3
6092
Night
12%9%31%32%12%1
16171

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 15thDay
6%6%1432333460%
1611
16th to endDay
7%5%15%422236%59%
1728
February1st to 15thDay
7%6%25%5%23246%53%
1591
16th to endDay
8%6%24423236%55%
1580
March1st to 15thDay
10%5%26%322445%52%
1972
16th to endDay
14%7%24313245%51%
2112
April1st to 15thDay
12%5%24323335%53%
2035
16th to endDay
14%7%35%33233448%
2316
May1st to 15thDay
11%5%14323345%53%
2331
16th to endDay
11%6%15%434436%47%
2430
June1st to 15thDay
6%31432335%5%58%
2340
16th to endDay
2112322448%64%
2340
July1st to 15thDay
7%41332446%7%55%
2340
16th to endDay
5%313434447%57%
2466
August1st to 15thDay
7%31342346%9%52%
2340
16th to endDay
6%31342345%8%57%
2435
September1st to 15thDay
11%414323445%52%
2007
16th to endDay
8%413423336%59%
1980
October1st to 15thDay
11%5%1331223457%
1848
16th to endDay
7%43323235%63%
1920
November1st to 15thDay
7%314322235%64%
1784
16th to endDay
8%41321122467%
1755
December1st to 15thDay
12%5%24323345%52%
1631
16th to endDay
10%6%25%32233454%
1728
January1st to 15thNight
6%413323245%62%
2327
16th to endNight
6%41331224464%
2496
February1st to 15thNight
8%7%25%31233457%
2273
16th to endNight
7%42332234460%
1894
March1st to 15thNight
9%5%23313345%57%
1986
16th to endNight
12%5%25%32223455%
2112
April1st to 15thNight
9%314312235%60%
1911
16th to endNight
12%5%13423336%53%
1641
May1st to 15thNight
11%313322335%57%
1619
16th to endNight
7%413423448%55%
1683
June1st to 15thNight
5%312323347%62%
1620
16th to endNight
1112224346%68%
1620
July1st to 15thNight
4213313348%62%
1620
16th to endNight
321333445%7%59%
1702
August1st to 15thNight
431242347%8%58%
1620
16th to endNight
5%314313245%62%
1767
September1st to 15thNight
8%314422435%58%
1951
16th to endNight
6%313313346%60%
1980
October1st to 15thNight
13%41332323457%
2100
16th to endNight
6%32212335%67%
2304
November1st to 15thNight
6%312213336%64%
2404
16th to endNight
10%31211224464%
2535
December1st to 15thNight
11%5%13322345%55%
2366
16th to endNight
9%5%1342333457%
2496

Percentage Cloud Cover SE (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 15thDay
8%7%25%334335%52%
1611
16th to endDay
9%5%26%5%23337%49%
1728
February1st to 15thDay
8%7%46%5%24347%45%
1591
16th to endDay
9%6%25%42335%6%48%
1580
March1st to 15thDay
11%6%35%4345%46%42%
1972
16th to endDay
20%9%24413345%40%
2110
April1st to 15thDay
14%6%24425%346%43%
2035
16th to endDay
17%7%35%423345%40%
2316
May1st to 15thDay
15%7%345%24447%39%
2331
16th to endDay
15%6%26%5%35%45%7%37%
2430
June1st to 15thDay
8%4145%25%46%8%48%
2340
16th to endDay
5%113325%45%11%54%
2340
July1st to 15thDay
9%414435%5%7%9%44%
2340
16th to endDay
6%3136%25%6%5%9%48%
2466
August1st to 15thDay
8%314425%5%6%10%46%
2340
16th to endDay
7%3244245%5%9%51%
2435
September1st to 15thDay
12%5%2432445%6%48%
2007
16th to endDay
9%41342335%7%54%
1980
October1st to 15thDay
12%6%13322446%52%
1848
16th to endDay
9%413323335%59%
1920
November1st to 15thDay
8%314423346%56%
1784
16th to endDay
10%423412236%59%
1755
December1st to 15thDay
14%6%3432345%6%45%
1631
16th to endDay
13%7%25%434446%42%
1728
January1st to 15thNight
8%5%2432425%5%55%
2327
16th to endNight
7%5%24324345%56%
2496
February1st to 15thNight
10%7%35%324446%46%
2273
16th to endNight
8%5%2342445%5%53%
1894
March1st to 15thNight
10%6%2442335%7%48%
1986
16th to endNight
17%6%25%323345%44%
2112
April1st to 15thNight
12%415%423347%52%
1911
16th to endNight
14%6%24423346%46%
1641
May1st to 15thNight
15%5%25%323447%46%
1619
16th to endNight
8%5%2442446%9%46%
1683
June1st to 15thNight
6%313335%46%8%53%
1620
16th to endNight
412325%5%5%8%60%
1620
July1st to 15thNight
6%22332445%10%52%
1620
16th to endNight
5%335%345%5%9%52%
1702
August1st to 15thNight
5%2144345%8%9%51%
1620
16th to endNight
5%424424347%55%
1767
September1st to 15thNight
9%425%423446%52%
1951
16th to endNight
7%413323347%56%
1980
October1st to 15thNight
14%5%23323245%52%
2100
16th to endNight
7%313223335%63%
2304
November1st to 15thNight
8%413323346%58%
2404
16th to endNight
11%413212345%57%
2535
December1st to 15thNight
12%6%2442345%6%48%
2366
16th to endNight
12%6%34424346%46%
2496

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 15thDay
35%212%28%19%2
1612
16th to endDay
36%114%27%17%2
1728
February1st to 15thDay
39%313%28%10%3
1592
16th to endDay
35%212%28%17%3
1580
March1st to 15thDay
41%310%24%16%3
1972
16th to endDay
46%410%24%11%2
2112
April1st to 15thDay
41%311%24%16%1
2035
16th to endDay
46%210%27%11%1
2316
May1st to 15thDay
44%312%22%15%1
2331
16th to endDay
45%5%12%22%12%1
2434
June1st to 15thDay
32%414%27%17%2
2340
16th to endDay
24%415%29%23%2
2340
July1st to 15thDay
32%5%15%29%14%2
2201
16th to endDay
28%5%15%31%15%2
2311
August1st to 15thDay
30%5%17%27%15%3
2326
16th to endDay
30%5%13%28%16%6%
2435
September1st to 15thDay
36%312%24%15%6%
2007
16th to endDay
29%211%31%21%3
1980
October1st to 15thDay
33%211%23%23%5%
1848
16th to endDay
28%210%29%22%6%
1920
November1st to 15thDay
29%211%27%21%7%
1784
16th to endDay
28%28%32%24%3
1755
December1st to 15thDay
38%313%29%14%
1631
16th to endDay
42%310%25%13%3
1728
January1st to 15thNight
31%211%29%22%3
2327
16th to endNight
29%213%30%20%4
2496
February1st to 15thNight
39%313%26%14%3
2283
16th to endNight
31%313%28%19%4
1894
March1st to 15thNight
34%311%23%19%6%
1986
16th to endNight
43%311%23%15%2
2112
April1st to 15thNight
33%211%25%22%3
1911
16th to endNight
38%312%22%18%3
1641
May1st to 15thNight
39%314%23%17%2
1620
16th to endNight
33%6%20%24%13%1
1685
June1st to 15thNight
27%418%29%16%2
1620
16th to endNight
21%414%34%20%4
1620
July1st to 15thNight
26%313%32%19%4
1530
16th to endNight
27%413%31%21%1
1594
August1st to 15thNight
25%5%16%31%15%4
1610
16th to endNight
28%311%26%23%6%
1767
September1st to 15thNight
32%313%23%17%8%
1951
16th to endNight
27%310%28%26%4
1980
October1st to 15thNight
35%38%21%23%8%
2100
16th to endNight
23%38%28%28%6%
2304
November1st to 15thNight
27%210%27%22%9%
2404
16th to endNight
29%19%30%23%5%
2535
December1st to 15thNight
36%212%30%17%1
2366
16th to endNight
38%213%24%14%5%
2496

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 15thDay
25%12%32%23%6%
90
16th to endDay
12%17%44%20%31
96
February1st to 15thDay
5%24%44%23%2
90
16th to endDay
9%24%38%24%11
81
March1st to 15thDay
18%21%45%11%3
90
16th to endDay
23%15%38%17%4
96
April1st to 15thDay
19%17%30%24%8%
154
16th to endDay
23%11%38%18%6%2
426
May1st to 15thDay
17%11%35%21%11%1
468
16th to endDay
17%8%32%27%10%3
517
June1st to 15thDay
8%428%35%19%2
495
16th to endDay
6%428%39%17%3
495
July1st to 15thDay
11%416%37%23%6%
475
16th to endDay
6%9%38%38%6%
515
August1st to 15thDay
9%12%37%35%5%
493
16th to endDay
8%213%37%32%6%
475
September1st to 15thDay
5%115%41%29%6%
162
16th to endDay
10%224%42%13%5%
135
October1st to 15thDay
12%6%38%25%8%8%
135
16th to endDay
11%9%41%28%7%2
144
November1st to 15thDay
16%8%32%25%14%2
135
16th to endDay
24%17%33%17%6%
135
December1st to 15thDay
15%15%39%20%5%3
94
16th to endDay
19%18%33%23%4
96
January1st to 15thNight
12%15%36%28%7%
900
16th to endNight
10%13%40%29%5%
960
February1st to 15thNight
14%13%40%27%3
875
16th to endNight
12%12%40%30%4
632
March1st to 15thNight
13%12%36%29%8%
546
16th to endNight
21%12%34%25%5%
576
April1st to 15thNight
14%15%38%24%6%
539
16th to endNight
17%10%37%26%6%
540
May1st to 15thNight
17%9%33%29%9%1
540
16th to endNight
11%6%31%34%13%2
563
June1st to 15thNight
7%5%30%38%17%
540
16th to endNight
4131%45%16%
540
July1st to 15thNight
7%117%48%23%1
510
16th to endNight
418%45%36%2
564
August1st to 15thNight
8%7%44%35%2
539
16th to endNight
6%13%39%35%3
573
September1st to 15thNight
11%318%40%22%4
540
16th to endNight
9%422%38%21%3
537
October1st to 15thNight
17%428%27%19%2
660
16th to endNight
8%11%36%30%11%
768
November1st to 15thNight
10%11%35%30%11%
884
16th to endNight
15%12%34%29%7%
975
December1st to 15thNight
16%11%35%29%5%
910
16th to endNight
15%11%33%33%5%
960
Page generated at 2017-12-03 10:16:40. Version ac04

Copyright 2017 A. Danko


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