Buffalo Point
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Buffalo Point clear sky chart from 2005-11-05 to 2017-10-31.

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
33%
16435
12%
47280
7%
16390
38%
16390
18%
33811

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
30%
900
8%
2685
5%
895
33%
895
12%
2065
January16th to endNight
22%
960
9%
2749
3%
960
28%
960
13%
2143
February1st to 15thNight
31%
878
14%
2288
6%
876
36%
876
19%
1633
February16th to endNight
33%
789
13%
2051
6%
789
37%
789
17%
1545
March1st to 15thNight
29%
594
14%
2034
9%
594
35%
594
15%
1425
March16th to endNight
32%
576
14%
2112
11%
576
40%
576
14%
1438
April1st to 15thNight
32%
539
16%
1741
11%
539
41%
539
20%
1106
April16th to endNight
31%
540
16%
1620
7%
540
40%
540
17%
1129
May1st to 15thNight
32%
540
13%
1470
5%
540
36%
540
21%
1030
May16th to endNight
39%
563
12%
1378
4%
561
42%
561
26%
943
June1st to 15thNight
37%
540
6%
1260
3%
540
40%
540
27%
876
June16th to endNight
44%
540
5%
1260
2%
540
47%
540
26%
892
July1st to 15thNight
56%
510
9%
1190
6%
510
59%
510
41%
729
July16th to endNight
51%
564
16%
1256
6%
531
57%
531
39%
787
August1st to 15thNight
59%
539
19%
1584
12%
536
63%
536
36%
895
August16th to endNight
53%
573
23%
1719
18%
573
61%
573
36%
961
September1st to 15thNight
49%
540
16%
1799
16%
540
53%
540
28%
1051
September16th to endNight
41%
543
17%
1986
17%
543
47%
543
23%
1228
October1st to 15thNight
31%
720
14%
2160
9%
720
35%
720
19%
1499
October16th to endNight
26%
852
12%
2411
5%
852
31%
852
15%
1843
November1st to 15thNight
22%
875
11%
2451
5%
875
27%
875
15%
1863
November16th to endNight
19%
900
9%
2520
5%
900
23%
900
10%
2059
December1st to 15thNight
21%
900
5%
2676
3%
900
23%
900
9%
2231
December16th to endNight
17%
960
7%
2880
2%
960
22%
960
7%
2440

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
13%8%36%6%35%5%5%7%34%
48498
Night
13%9%47%6%35%45%7%33%
47428
Cloud CoverDay
10%7%25%5%34446%44%
48508
Night
10%8%36%5%34446%43%
47431
Cloud CoverDay
12%8%36%6%35%5%5%7%34%
48509
Night
13%9%47%6%35%45%7%33%
47432
Cloud CoverDay
13%8%36%5%35%5%5%7%34%
48507
Night
13%9%47%6%35%45%7%32%
47432
TransparencyDay
48%7%15%20%7%
48163
Night
49%6%14%20%8%
47280
SeeingDay
15%13%25%26%14%3
6392
Night
14%18%25%27%12%1
16437

By Month

Percentage Cloud Cover NE (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
10%10%5%9%7%46%47%10%23%
1253
16th to endDay
11%12%5%11%8%5%7%5%6%8%15%
1473
February1st to 15thDay
7%8%46%7%5%7%6%6%8%30%
1575
16th to endDay
8%12%5%8%6%36%6%6%7%27%
1422
March1st to 15thDay
13%11%46%5%35%45%7%32%
1925
16th to endDay
13%10%47%5%345%6%6%33%
2112
April1st to 15thDay
11%8%25%5%35%6%5%8%38%
2204
16th to endDay
16%8%36%5%245%47%34%
2340
May1st to 15thDay
17%7%45%6%35%45%7%32%
2479
16th to endDay
16%6%25%5%35%45%7%37%
2734
June1st to 15thDay
16%6%25%5%35%5%6%7%35%
2700
16th to endDay
12%5%25%5%36%6%6%9%37%
2700
July1st to 15thDay
9%324435%5%6%10%45%
2700
16th to endDay
6%314435%5%5%9%48%
2827
August1st to 15thDay
10%4245%346%6%8%43%
2365
16th to endDay
10%5%2442445%8%47%
2483
September1st to 15thDay
11%6%25%5%25%447%44%
2160
16th to endDay
16%7%25%5%2446%6%37%
1962
October1st to 15thDay
17%11%37%5%34436%30%
1800
16th to endDay
19%10%48%6%35%45%6%24%
1809
November1st to 15thDay
14%12%6%8%6%35%445%28%
1407
16th to endDay
14%14%6%13%9%5%5%435%15%
1440
December1st to 15thDay
11%14%9%10%10%37%6%5%5%14%
1284
16th to endDay
14%14%7%12%8%4436%5%16%
1344
January1st to 15thNight
9%11%6%9%7%47%6%7%8%21%
2685
16th to endNight
11%11%6%9%7%37%5%7%9%19%
2749
February1st to 15thNight
8%8%47%7%36%5%6%9%32%
2285
16th to endNight
9%10%48%8%36%5%5%7%29%
2051
March1st to 15thNight
9%11%6%8%6%25%45%6%32%
2022
16th to endNight
16%9%36%425%5%46%34%
2112
April1st to 15thNight
13%8%35%42446%6%40%
1741
16th to endNight
16%9%35%5%35%245%37%
1620
May1st to 15thNight
18%7%26%433447%37%
1470
16th to endNight
16%5%243235%47%42%
1377
June1st to 15thNight
17%5%2432445%6%43%
1260
16th to endNight
10%4345%45%5%5%9%40%
1260
July1st to 15thNight
6%212415%46%7%56%
1260
16th to endNight
8%31322346%10%53%
1341
August1st to 15thNight
9%31332345%7%55%
1593
16th to endNight
9%31322335%8%55%
1719
September1st to 15thNight
11%41442425%6%52%
1799
16th to endNight
17%6%2442345%7%41%
1986
October1st to 15thNight
16%8%35%5%24447%36%
2160
16th to endNight
18%11%37%5%35%45%6%27%
2411
November1st to 15thNight
16%11%6%9%5%35%445%27%
2451
16th to endNight
16%12%6%11%9%45%445%19%
2520
December1st to 15thNight
9%15%6%12%11%5%7%6%5%5%14%
2676
16th to endNight
15%16%6%11%9%35%446%14%
2880

Percentage Cloud Cover NW (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
5%9%38%6%25%46%9%36%
1254
16th to endDay
8%11%39%7%46%5%5%7%30%
1473
February1st to 15thDay
7%7%36%5%46%5%5%7%40%
1575
16th to endDay
5%10%36%5%345%6%6%41%
1422
March1st to 15thDay
9%8%36%5%3335%5%45%
1936
16th to endDay
8%8%36%5%33445%46%
2110
April1st to 15thDay
9%7%14432447%49%
2204
16th to endDay
13%8%26%5%23245%44%
2340
May1st to 15thDay
13%7%25%424445%45%
2479
16th to endDay
13%5%145%24335%48%
2734
June1st to 15thDay
13%5%25%424446%46%
2700
16th to endDay
11%415%4235%6%7%48%
2700
July1st to 15thDay
8%31343345%7%55%
2700
16th to endDay
6%313434447%56%
2827
August1st to 15thDay
9%4134245%5%7%50%
2365
16th to endDay
9%414423446%52%
2483
September1st to 15thDay
11%5%24423347%47%
2160
16th to endDay
13%5%145%2445%6%45%
1962
October1st to 15thDay
16%11%36%5%33335%36%
1800
16th to endDay
16%10%46%5%25%5%45%33%
1809
November1st to 15thDay
11%11%46%6%2334441%
1407
16th to endDay
12%11%313%9%45%42329%
1440
December1st to 15thDay
7%12%411%9%36%5%5%5%28%
1284
16th to endDay
10%13%5%11%7%45%34429%
1344
January1st to 15thNight
6%9%38%7%446%5%6%35%
2685
16th to endNight
8%11%47%6%345%6%8%32%
2749
February1st to 15thNight
6%8%37%6%3445%6%42%
2278
16th to endNight
6%8%37%7%35%446%41%
2051
March1st to 15thNight
7%9%36%5%23445%45%
2034
16th to endNight
11%9%26%423445%45%
2110
April1st to 15thNight
11%6%24423345%50%
1741
16th to endNight
14%8%35%5%3333445%
1620
May1st to 15thNight
15%5%14323246%49%
1469
16th to endNight
12%414323446%51%
1378
June1st to 15thNight
14%414323345%52%
1260
16th to endNight
8%42433335%7%52%
1260
July1st to 15thNight
432313348%64%
1260
16th to endNight
7%313213347%60%
1341
August1st to 15thNight
7%31232235%7%59%
1593
16th to endNight
8%413313346%60%
1719
September1st to 15thNight
11%413323345%55%
1799
16th to endNight
14%5%24322346%49%
1986
October1st to 15thNight
14%9%25%423446%41%
2160
16th to endNight
15%10%36%6%34445%33%
2411
November1st to 15thNight
12%11%37%5%23345%40%
2451
16th to endNight
11%12%49%8%3443432%
2520
December1st to 15thNight
6%12%5%9%10%46%445%29%
2676
16th to endNight
12%14%411%8%4444427%
2880

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
9%10%6%8%7%46%46%10%23%
1253
16th to endDay
11%12%6%11%9%5%7%5%7%7%15%
1473
February1st to 15thDay
7%8%46%7%47%6%6%8%29%
1575
16th to endDay
8%12%5%8%6%36%6%6%8%27%
1422
March1st to 15thDay
12%11%46%5%45%45%7%31%
1936
16th to endDay
13%10%36%5%3446%7%33%
2112
April1st to 15thDay
11%7%35%5%35%6%5%8%38%
2204
16th to endDay
16%8%36%6%245%47%34%
2340
May1st to 15thDay
17%7%45%6%35%45%7%32%
2479
16th to endDay
16%6%245%35%45%7%37%
2734
June1st to 15thDay
15%6%35%6%36%46%7%34%
2700
16th to endDay
12%5%25%5%36%6%6%9%36%
2700
July1st to 15thDay
9%3145%35%5%6%10%45%
2700
16th to endDay
6%324435%5%6%9%47%
2827
August1st to 15thDay
10%4145%346%6%8%43%
2365
16th to endDay
10%5%2442445%8%47%
2483
September1st to 15thDay
11%6%25%5%24448%44%
2160
16th to endDay
15%7%25%42446%7%37%
1962
October1st to 15thDay
17%11%47%5%34436%30%
1800
16th to endDay
19%10%48%6%35%5%5%6%24%
1809
November1st to 15thDay
14%12%6%8%6%35%445%27%
1407
16th to endDay
14%13%6%13%10%5%5%446%15%
1440
December1st to 15thDay
11%14%8%10%10%37%5%5%6%13%
1284
16th to endDay
14%14%7%13%8%4436%5%16%
1344
January1st to 15thNight
9%11%6%9%7%5%6%7%7%8%20%
2685
16th to endNight
11%11%6%9%7%36%5%7%9%19%
2749
February1st to 15thNight
8%8%48%7%36%5%5%9%32%
2278
16th to endNight
9%10%48%7%37%5%5%7%28%
2051
March1st to 15thNight
9%11%5%8%6%35%5%5%6%31%
2034
16th to endNight
16%9%36%425%45%6%33%
2112
April1st to 15thNight
13%8%35%42446%6%40%
1741
16th to endNight
16%9%35%6%35%345%36%
1620
May1st to 15thNight
19%7%35%333447%37%
1469
16th to endNight
15%6%25%3235%48%42%
1377
June1st to 15thNight
17%5%2433445%6%43%
1260
16th to endNight
10%4345%36%5%6%8%40%
1260
July1st to 15thNight
6%212415%46%8%56%
1260
16th to endNight
7%31322346%9%53%
1341
August1st to 15thNight
9%41331345%7%55%
1593
16th to endNight
8%41322345%8%55%
1719
September1st to 15thNight
11%5%1442435%6%52%
1799
16th to endNight
17%6%2432345%7%41%
1986
October1st to 15thNight
15%8%36%5%245%47%36%
2160
16th to endNight
18%12%47%5%35%45%5%27%
2411
November1st to 15thNight
16%11%6%9%6%34445%27%
2451
16th to endNight
16%12%5%11%9%45%5%45%18%
2520
December1st to 15thNight
9%15%7%12%11%5%7%6%5%5%14%
2676
16th to endNight
15%16%6%12%9%35%446%14%
2880

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
9%11%5%9%7%45%47%10%23%
1253
16th to endDay
11%12%5%12%8%5%7%6%6%7%15%
1473
February1st to 15thDay
7%8%47%7%48%5%7%8%29%
1575
16th to endDay
8%12%5%7%6%45%5%7%8%27%
1422
March1st to 15thDay
13%10%46%5%35%45%7%32%
1936
16th to endDay
13%10%37%5%3446%6%34%
2110
April1st to 15thDay
10%8%345%35%6%5%8%38%
2204
16th to endDay
16%8%46%5%34447%34%
2340
May1st to 15thDay
17%7%45%5%3445%7%32%
2479
16th to endDay
16%6%25%5%3445%7%37%
2734
June1st to 15thDay
15%6%35%5%35%5%5%7%35%
2700
16th to endDay
12%5%25%436%6%6%9%37%
2700
July1st to 15thDay
9%3144345%6%10%45%
2700
16th to endDay
7%314435%5%5%10%48%
2827
August1st to 15thDay
10%425%5%345%6%8%44%
2365
16th to endDay
10%5%2432445%7%48%
2483
September1st to 15thDay
11%6%25%424448%44%
2160
16th to endDay
16%7%35%5%1446%7%37%
1962
October1st to 15thDay
17%13%37%5%34446%30%
1800
16th to endDay
19%11%5%8%6%3445%5%24%
1809
November1st to 15thDay
14%13%6%9%6%3444427%
1407
16th to endDay
14%13%6%14%10%5%5%435%15%
1440
December1st to 15thDay
11%15%8%11%10%38%6%46%13%
1284
16th to endDay
13%15%7%13%8%4445%5%16%
1344
January1st to 15thNight
9%11%6%9%8%47%7%6%8%21%
2685
16th to endNight
11%12%6%9%7%36%5%7%9%19%
2749
February1st to 15thNight
8%8%47%7%36%5%6%8%32%
2278
16th to endNight
9%10%5%7%8%37%5%5%7%29%
2051
March1st to 15thNight
9%10%5%8%7%245%5%6%32%
2034
16th to endNight
16%9%36%425%447%34%
2112
April1st to 15thNight
12%8%45%42445%6%40%
1741
16th to endNight
16%9%35%6%35%345%37%
1620
May1st to 15thNight
19%7%25%433447%37%
1469
16th to endNight
16%5%25%3235%5%8%41%
1377
June1st to 15thNight
17%5%2422346%6%43%
1260
16th to endNight
10%5%345%45%5%5%9%40%
1260
July1st to 15thNight
6%212325%46%8%55%
1260
16th to endNight
8%31422246%9%53%
1341
August1st to 15thNight
9%31331346%7%55%
1593
16th to endNight
9%41332336%7%55%
1719
September1st to 15thNight
12%41342435%6%51%
1799
16th to endNight
18%5%25%31345%8%40%
1986
October1st to 15thNight
16%9%37%43345%7%34%
2160
16th to endNight
18%12%47%5%35%446%26%
2411
November1st to 15thNight
16%12%7%8%5%35%345%27%
2451
16th to endNight
16%12%6%12%10%45%445%18%
2520
December1st to 15thNight
9%15%7%12%11%5%7%6%45%14%
2676
16th to endNight
16%16%6%11%9%35%446%14%
2880

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
55%6%15%18%4
1254
16th to endDay
65%6%9%14%3
1473
February1st to 15thDay
49%9%15%17%8%
1576
16th to endDay
54%7%13%16%7%
1422
March1st to 15thDay
52%6%15%17%7%
1936
16th to endDay
51%6%15%19%6%1
2112
April1st to 15thDay
43%6%12%22%12%1
2204
16th to endDay
50%6%12%19%10%1
2340
May1st to 15thDay
52%6%12%21%6%
2479
16th to endDay
47%7%12%18%13%
2738
June1st to 15thDay
48%8%15%19%8%
2700
16th to endDay
43%9%20%21%4
2700
July1st to 15thDay
34%8%17%30%7%
2541
16th to endDay
34%9%18%26%10%
2649
August1st to 15thDay
37%9%21%25%5%1
2350
16th to endDay
34%7%18%29%9%
2483
September1st to 15thDay
39%6%17%28%7%
2160
16th to endDay
44%8%15%26%4
1962
October1st to 15thDay
54%6%13%20%5%
1800
16th to endDay
57%9%14%15%2
1809
November1st to 15thDay
57%6%15%14%41
1407
16th to endDay
67%7%12%8%3
1440
December1st to 15thDay
66%9%12%9%2
1284
16th to endDay
69%6%8%10%4
1344
January1st to 15thNight
57%8%13%17%4
2685
16th to endNight
58%7%12%16%4
2749
February1st to 15thNight
47%5%18%18%9%
2288
16th to endNight
52%7%13%20%5%
2051
March1st to 15thNight
50%7%13%18%10%
2034
16th to endNight
50%6%14%19%8%1
2112
April1st to 15thNight
41%5%12%22%15%2
1741
16th to endNight
49%48%21%14%2
1620
May1st to 15thNight
47%5%11%24%10%
1470
16th to endNight
40%6%13%22%15%2
1378
June1st to 15thNight
40%5%16%23%12%
1260
16th to endNight
40%8%20%23%6%1
1260
July1st to 15thNight
24%7%19%35%10%1
1190
16th to endNight
27%7%15%30%18%1
1256
August1st to 15thNight
27%6%18%36%10%1
1584
16th to endNight
26%6%16%36%12%
1719
September1st to 15thNight
32%7%18%30%10%
1799
16th to endNight
40%6%18%26%8%
1986
October1st to 15thNight
46%8%15%20%9%
2160
16th to endNight
56%7%13%19%3
2411
November1st to 15thNight
57%5%13%16%5%1
2451
16th to endNight
62%8%12%11%4
2520
December1st to 15thNight
66%8%12%11%1
2676
16th to endNight
69%7%10%9%2
2880

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
14%8%28%31%16%
90
16th to endDay
21%30%36%10%1
96
February1st to 15thDay
12%8%48%23%6%
90
16th to endDay
22%440%23%6%2
81
March1st to 15thDay
16%7%30%30%14%1
90
16th to endDay
13%5%30%33%14%3
96
April1st to 15thDay
13%19%27%27%9%1
323
16th to endDay
20%18%22%26%10%1
450
May1st to 15thDay
19%20%26%21%8%2
468
16th to endDay
19%16%21%25%13%3
517
June1st to 15thDay
16%17%27%22%12%2
495
16th to endDay
15%17%20%27%15%3
495
July1st to 15thDay
12%12%19%29%20%6%
475
16th to endDay
8%16%20%29%19%5%
515
August1st to 15thDay
9%9%22%27%21%8%
493
16th to endDay
12%10%22%28%22%4
523
September1st to 15thDay
13%9%27%31%15%2
315
16th to endDay
17%14%36%22%6%2
135
October1st to 15thDay
15%15%31%28%8%
135
16th to endDay
24%11%31%27%41
144
November1st to 15thDay
17%7%26%31%16%
90
16th to endDay
41%7%31%13%42
90
December1st to 15thDay
14%6%32%34%11%1
90
16th to endDay
14%447%21%7%4
96
January1st to 15thNight
12%21%24%29%10%2
900
16th to endNight
14%21%30%25%7%
960
February1st to 15thNight
12%20%25%28%11%2
880
16th to endNight
11%19%24%27%12%3
789
March1st to 15thNight
12%21%27%25%12%
594
16th to endNight
16%20%23%23%12%3
576
April1st to 15thNight
14%21%26%26%10%
539
16th to endNight
19%20%20%27%10%
540
May1st to 15thNight
19%19%22%28%9%1
540
16th to endNight
16%18%21%29%13%
563
June1st to 15thNight
18%19%21%27%13%
540
16th to endNight
9%21%18%30%18%1
540
July1st to 15thNight
6%15%18%37%20%2
510
16th to endNight
7%19%16%34%20%1
564
August1st to 15thNight
10%10%15%35%25%2
539
16th to endNight
9%12%21%32%22%1
573
September1st to 15thNight
10%11%24%33%17%2
540
16th to endNight
15%12%26%29%14%1
543
October1st to 15thNight
17%15%29%29%7%
720
16th to endNight
20%15%29%25%6%1
852
November1st to 15thNight
17%19%33%19%9%1
875
16th to endNight
17%23%28%22%7%
900
December1st to 15thNight
13%20%27%27%9%
900
16th to endNight
19%21%25%22%9%1
960
Page generated at 2017-11-01 16:23:34. Version ac04

Copyright 2017 A. Danko


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