Buffalo Camp
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Buffalo Camp clear sky chart from 2005-11-06 to 2026-01-02.

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 Type	Minimum conditions for hour to be usable				Out of hours
	Clear of Clouds	Transparency	Seeing	Sky Brightness
Planetary:	50%	(no limit)	Average	(no limit)	Nighttime Hours
Deep Sky:	70%	Average	(no limit)	5.9	Nighttime Hours
CCD Imaging:	70%	Below Average	Poor	(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

By Month

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 Forecast	Data Points
Cloud Cover	Day	7% 7% 3 7% 5% 4 5% 4 6% 8% 45%	136659
	Night	7% 8% 3 7% 5% 4 5% 4 6% 8% 43%	132059
Transparency	Day	36% 6% 13% 26% 15% 4	131329
	Night	38% 6% 14% 25% 14% 3	128395
Seeing	Day	11% 9% 27% 31% 17% 4	17362
	Night	11% 8% 27% 39% 15% 1	26919

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
Month	Days in Month		Occurrence of each Forecast	Data Points
January	1st to 10th	Day	7% 16% 5% 10% 6% 5% 6% 5% 7% 7% 25%	3186
	11th to 20th	Day	3 11% 5% 9% 7% 6% 6% 5% 6% 9% 32%	3482
	21st to end	Day	3 9% 4 7% 4 4 4 3 6% 7% 49%	4211
February	1st to 10th	Day	8% 13% 5% 11% 7% 6% 6% 4 6% 9% 27%	1800
	11th to 20th	Day	7% 12% 6% 9% 8% 5% 5% 5% 6% 8% 30%	1755
	21st to end	Day	5% 11% 5% 11% 6% 7% 5% 4 6% 7% 34%	1530
March	1st to 10th	Day	4 7% 4 10% 7% 7% 6% 5% 6% 7% 37%	4674
	11th to 20th	Day	4 7% 3 7% 5% 5% 6% 5% 7% 11% 40%	5000
	21st to end	Day	13% 15% 5% 12% 5% 5% 5% 4 6% 8% 23%	5630
April	1st to 10th	Day	9% 9% 2 8% 6% 5% 6% 4 6% 9% 37%	2400
	11th to 20th	Day	11% 12% 4 9% 5% 5% 4 4 6% 7% 32%	2423
	21st to end	Day	12% 11% 3 7% 5% 4 5% 5% 6% 8% 36%	2625
May	1st to 10th	Day	14% 7% 2 6% 5% 4 4 4 6% 7% 41%	6340
	11th to 20th	Day	13% 6% 3 8% 5% 5% 5% 5% 7% 8% 34%	6298
	21st to end	Day	11% 4 2 6% 4 5% 5% 4 7% 8% 43%	6925
June	1st to 10th	Day	12% 5% 2 5% 5% 4 5% 4 6% 9% 43%	2910
	11th to 20th	Day	11% 5% 3 6% 5% 4 5% 4 6% 8% 43%	3000
	21st to end	Day	5% 3 1 4 4 4 5% 4 7% 9% 54%	3000
July	1st to 10th	Day	3 2 1 5% 4 5% 5% 5% 7% 10% 53%	6779
	11th to 20th	Day	6% 2 1 3 2 3 3 3 5% 9% 62%	6615
	21st to end	Day	4 3 1 4 3 3 4 4 6% 9% 57%	6903
August	1st to 10th	Day	5% 4 2 6% 4 5% 5% 4 7% 10% 50%	6063
	11th to 20th	Day	4 3 1 4 3 3 4 3 6% 9% 62%	5798
	21st to end	Day	8% 4 1 4 3 3 3 3 4 6% 60%	6253
September	1st to 10th	Day	8% 4 2 4 3 3 3 3 5% 8% 58%	2400
	11th to 20th	Day	10% 4 2 5% 5% 4 4 3 7% 8% 49%	2400
	21st to end	Day	11% 5% 2 4 3 3 2 3 5% 7% 56%	2108
October	1st to 10th	Day	8% 5% 2 5% 3 3 3 2 4 7% 57%	3270
	11th to 20th	Day	8% 5% 2 5% 3 3 4 3 4 8% 55%	3250
	21st to end	Day	5% 5% 1 6% 4 4 5% 4 6% 9% 52%	3339
November	1st to 10th	Day	10% 9% 3 7% 6% 4 4 4 4 7% 42%	1663
	11th to 20th	Day	6% 7% 3 6% 5% 5% 5% 5% 7% 9% 42%	1680
	21st to end	Day	7% 10% 3 9% 6% 5% 6% 4 6% 7% 37%	1680
December	1st to 10th	Day	6% 12% 4 10% 5% 5% 4 4 7% 7% 36%	2700
	11th to 20th	Day	6% 13% 4 11% 5% 5% 5% 4 5% 7% 34%	2994
	21st to end	Day	6% 8% 4 10% 6% 6% 5% 5% 6% 6% 38%	3575
January	1st to 10th	Night	5% 13% 4 10% 6% 6% 5% 5% 6% 8% 30%	6782
	11th to 20th	Night	4 11% 6% 12% 6% 5% 5% 4 5% 7% 36%	6475
	21st to end	Night	3 8% 4 10% 5% 5% 5% 4 6% 9% 42%	6812
February	1st to 10th	Night	7% 13% 5% 11% 6% 6% 6% 4 7% 7% 29%	2600
	11th to 20th	Night	5% 11% 5% 13% 7% 6% 5% 4 6% 7% 31%	2532
	21st to end	Night	6% 10% 4 8% 6% 6% 5% 5% 6% 7% 37%	2100
March	1st to 10th	Night	6% 8% 3 7% 4 4 5% 5% 8% 10% 39%	5207
	11th to 20th	Night	7% 7% 2 6% 5% 4 5% 4 7% 9% 43%	5000
	21st to end	Night	14% 15% 5% 13% 6% 6% 5% 4 6% 7% 18%	5337
April	1st to 10th	Night	9% 10% 3 7% 6% 5% 4 5% 5% 7% 40%	2000
	11th to 20th	Night	11% 10% 3 8% 5% 6% 5% 5% 6% 7% 34%	1923
	21st to end	Night	12% 7% 3 8% 4 4 5% 5% 7% 8% 37%	1774
May	1st to 10th	Night	11% 6% 2 5% 3 4 4 3 6% 8% 49%	3640
	11th to 20th	Night	15% 8% 3 8% 5% 5% 5% 5% 7% 9% 31%	3617
	21st to end	Night	10% 5% 2 5% 3 3 3 3 6% 8% 52%	3972
June	1st to 10th	Night	10% 6% 2 5% 5% 5% 6% 4 6% 8% 42%	1487
	11th to 20th	Night	12% 5% 2 6% 5% 5% 5% 4 6% 8% 42%	1400
	21st to end	Night	6% 3 1 4 4 4 5% 4 6% 7% 57%	1400
July	1st to 10th	Night	5% 4 1 5% 3 4 4 4 6% 9% 56%	3180
	11th to 20th	Night	7% 3 1 4 3 3 4 4 5% 8% 60%	3336
	21st to end	Night	6% 4 1 5% 4 4 5% 5% 7% 9% 49%	3970
August	1st to 10th	Night	8% 5% 2 7% 5% 4 4 4 6% 8% 48%	3746
	11th to 20th	Night	5% 3 2 4 4 4 4 5% 7% 9% 53%	4051
	21st to end	Night	9% 4 2 5% 3 3 4 3 4 7% 55%	4724
September	1st to 10th	Night	8% 3 1 4 3 3 4 4 5% 8% 58%	2000
	11th to 20th	Night	10% 5% 2 5% 4 4 4 3 5% 8% 51%	2000
	21st to end	Night	10% 5% 2 4 2 3 3 3 5% 7% 57%	2290
October	1st to 10th	Night	9% 6% 2 5% 3 3 3 3 5% 6% 55%	3920
	11th to 20th	Night	6% 5% 2 5% 4 4 4 3 5% 8% 54%	3898
	21st to end	Night	6% 6% 3 6% 5% 4 5% 4 6% 8% 48%	4414
November	1st to 10th	Night	10% 10% 2 6% 4 4 5% 4 6% 7% 40%	2850
	11th to 20th	Night	6% 9% 3 8% 5% 5% 5% 5% 7% 8% 40%	2940
	21st to end	Night	6% 9% 3 8% 5% 5% 5% 4 7% 8% 41%	2940
December	1st to 10th	Night	6% 12% 4 9% 6% 5% 6% 5% 7% 9% 31%	4710
	11th to 20th	Night	6% 14% 5% 10% 5% 5% 5% 3 6% 6% 34%	5409
	21st to end	Night	6% 8% 3 7% 4 4 5% 4 6% 7% 46%	7623

Transparency (when cloud cover <= 30%)
Color Meanings: Too cloudy to forecast Poor Below Average Average Above average Transparent
Month	Days in Month		Occurrence of each Forecast	Data Points
January	1st to 10th	Day	54% 8% 15% 20% 3	3186
	11th to 20th	Day	47% 7% 14% 18% 13% 1	3482
	21st to end	Day	34% 6% 21% 33% 7%	4211
February	1st to 10th	Day	53% 6% 15% 18% 8%	1800
	11th to 20th	Day	51% 7% 15% 19% 7% 1	1764
	21st to end	Day	47% 6% 17% 20% 8% 1	1530
March	1st to 10th	Day	43% 7% 12% 28% 10%	4674
	11th to 20th	Day	35% 8% 21% 27% 10%	5000
	21st to end	Day	57% 7% 15% 17% 3	5630
April	1st to 10th	Day	42% 8% 15% 24% 9% 1	2400
	11th to 20th	Day	48% 7% 13% 23% 8% 1	2426
	21st to end	Day	44% 7% 13% 24% 11% 1	2625
May	1st to 10th	Day	40% 6% 10% 24% 16% 3	6340
	11th to 20th	Day	44% 8% 12% 26% 9% 2	6302
	21st to end	Day	34% 8% 12% 28% 16% 2	6926
June	1st to 10th	Day	36% 8% 14% 28% 13% 2	2910
	11th to 20th	Day	36% 7% 15% 24% 15% 3	3000
	21st to end	Day	24% 6% 14% 34% 18% 4	3000
July	1st to 10th	Day	25% 5% 13% 29% 20% 9%	6706
	11th to 20th	Day	21% 4 10% 27% 24% 13%	6534
	21st to end	Day	23% 4 10% 24% 23% 15%	6705
August	1st to 10th	Day	25% 5% 8% 27% 23% 11%	4416
	11th to 20th	Day	24% 4 11% 32% 23% 5%	4197
	21st to end	Day	24% 3 8% 31% 28% 5%	4508
September	1st to 10th	Day	26% 4 9% 30% 23% 8%	2400
	11th to 20th	Day	30% 6% 15% 28% 16% 5%	2400
	21st to end	Day	28% 4 10% 31% 23% 5%	2108
October	1st to 10th	Day	29% 3 8% 33% 21% 6%	3270
	11th to 20th	Day	29% 3 13% 32% 20% 2	3250
	21st to end	Day	29% 5% 12% 33% 19% 2	3339
November	1st to 10th	Day	42% 6% 14% 24% 12% 2	1663
	11th to 20th	Day	36% 8% 21% 24% 10% 1	1680
	21st to end	Day	44% 8% 18% 20% 9% 1	1680
December	1st to 10th	Day	46% 5% 21% 20% 7%	2700
	11th to 20th	Day	49% 6% 19% 23% 3 1	2992
	21st to end	Day	43% 6% 10% 24% 13% 4	3575
January	1st to 10th	Night	48% 7% 20% 19% 6%	6782
	11th to 20th	Night	48% 5% 15% 15% 16% 1	6475
	21st to end	Night	37% 8% 20% 27% 7% 1	6812
February	1st to 10th	Night	52% 8% 14% 17% 8% 1	2600
	11th to 20th	Night	49% 8% 15% 19% 8% 1	2533
	21st to end	Night	44% 6% 15% 22% 11% 1	2100
March	1st to 10th	Night	36% 6% 14% 29% 14%	5207
	11th to 20th	Night	34% 8% 16% 33% 9%	5000
	21st to end	Night	62% 8% 14% 11% 5%	5337
April	1st to 10th	Night	43% 6% 15% 22% 13% 2	2000
	11th to 20th	Night	46% 8% 12% 21% 10% 2	1923
	21st to end	Night	41% 7% 14% 22% 14% 1	1774
May	1st to 10th	Night	33% 6% 10% 28% 21% 4	3640
	11th to 20th	Night	45% 8% 13% 25% 8% 1	3618
	21st to end	Night	28% 7% 12% 30% 20% 2	3972
June	1st to 10th	Night	38% 7% 14% 25% 14% 2	1487
	11th to 20th	Night	38% 7% 13% 24% 16% 2	1400
	21st to end	Night	25% 6% 15% 31% 21% 3	1400
July	1st to 10th	Night	25% 5% 17% 27% 19% 8%	3145
	11th to 20th	Night	23% 4 13% 26% 24% 10%	3294
	21st to end	Night	29% 5% 10% 22% 25% 8%	3856
August	1st to 10th	Night	30% 4 9% 22% 24% 10%	2717
	11th to 20th	Night	26% 5% 17% 29% 19% 4	2928
	21st to end	Night	28% 4 9% 29% 24% 5%	3400
September	1st to 10th	Night	25% 5% 8% 28% 23% 10%	2000
	11th to 20th	Night	32% 6% 12% 27% 18% 6%	2000
	21st to end	Night	28% 4 10% 28% 25% 5%	2290
October	1st to 10th	Night	30% 5% 8% 28% 25% 4	3920
	11th to 20th	Night	29% 4 10% 31% 24% 2	3898
	21st to end	Night	33% 6% 12% 29% 17% 3	4414
November	1st to 10th	Night	41% 7% 15% 23% 11% 3	2850
	11th to 20th	Night	39% 8% 17% 25% 10% 1	2940
	21st to end	Night	39% 7% 20% 24% 10% 1	2940
December	1st to 10th	Night	49% 7% 18% 19% 7% 1	4710
	11th to 20th	Night	49% 5% 20% 20% 5%	5410
	21st to end	Night	36% 5% 11% 30% 14% 4	7623

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
Month	Days in Month		Occurrence of each Forecast	Data Points
January	1st to 10th	Day	10% 11% 25% 28% 18% 7%	202
	11th to 20th	Day	13% 6% 24% 35% 15% 6%	267
	21st to end	Day	8% 11% 30% 34% 15% 2	330
February	1st to 10th	Day	19% 7% 32% 33% 9% 1	300
	11th to 20th	Day	10% 9% 34% 32% 14% 2	300
	21st to end	Day	10% 7% 37% 31% 12% 3	249
March	1st to 10th	Day	10% 12% 32% 32% 11% 4	370
	11th to 20th	Day	11% 10% 32% 32% 11% 4	500
	21st to end	Day	14% 9% 30% 27% 16% 4	550
April	1st to 10th	Day	17% 12% 31% 29% 10%	500
	11th to 20th	Day	16% 15% 36% 24% 8% 1	492
	21st to end	Day	18% 11% 22% 33% 15% 1	525
May	1st to 10th	Day	14% 11% 22% 28% 21% 4	703
	11th to 20th	Day	14% 8% 25% 28% 20% 5%	725
	21st to end	Day	16% 9% 21% 28% 21% 5%	789
June	1st to 10th	Day	12% 10% 26% 27% 20% 5%	730
	11th to 20th	Day	14% 14% 33% 25% 11% 3	730
	21st to end	Day	8% 8% 25% 33% 21% 4	730
July	1st to 10th	Day	6% 5% 22% 39% 24% 4	721
	11th to 20th	Day	5% 5% 27% 40% 19% 4	718
	21st to end	Day	4 4 23% 37% 24% 7%	794
August	1st to 10th	Day	5% 6% 22% 40% 21% 6%	658
	11th to 20th	Day	8% 5% 19% 35% 23% 10%	517
	21st to end	Day	8% 7% 22% 32% 25% 7%	583
September	1st to 10th	Day	8% 7% 26% 33% 20% 7%	530
	11th to 20th	Day	10% 7% 26% 29% 22% 7%	530
	21st to end	Day	13% 8% 26% 26% 19% 7%	429
October	1st to 10th	Day	17% 6% 23% 29% 19% 6%	330
	11th to 20th	Day	17% 9% 26% 30% 14% 4	330
	21st to end	Day	12% 15% 39% 21% 11% 2	363
November	1st to 10th	Day	18% 14% 30% 22% 13% 2	330
	11th to 20th	Day	11% 12% 38% 27% 11% 2	330
	21st to end	Day	12% 9% 34% 29% 15% 2	330
December	1st to 10th	Day	13% 11% 35% 25% 14% 3	330
	11th to 20th	Day	14% 9% 36% 27% 13% 2	305
	21st to end	Day	11% 7% 30% 32% 17% 4	242
January	1st to 10th	Night	10% 7% 30% 38% 14% 1	1006
	11th to 20th	Night	11% 10% 29% 36% 13% 1	1000
	21st to end	Night	11% 10% 32% 37% 10% 1	1029
February	1st to 10th	Night	11% 10% 24% 38% 16% 1	800
	11th to 20th	Night	9% 8% 30% 42% 10% 1	784
	21st to end	Night	8% 8% 26% 37% 17% 3	660
March	1st to 10th	Night	8% 8% 31% 37% 16% 1	800
	11th to 20th	Night	12% 6% 28% 40% 13% 1	800
	21st to end	Night	13% 9% 24% 38% 15% 1	818
April	1st to 10th	Night	14% 9% 26% 38% 13%	600
	11th to 20th	Night	16% 10% 31% 33% 10% 1	593
	21st to end	Night	15% 8% 25% 40% 12%	600
May	1st to 10th	Night	14% 5% 24% 41% 15% 1	600
	11th to 20th	Night	13% 7% 19% 39% 21% 1	591
	21st to end	Night	15% 7% 25% 34% 18% 2	650
June	1st to 10th	Night	11% 7% 26% 34% 20% 2	487
	11th to 20th	Night	14% 9% 28% 39% 10%	400
	21st to end	Night	6% 6% 24% 45% 18% 1	400
July	1st to 10th	Night	9% 4 21% 49% 17% 1	390
	11th to 20th	Night	7% 5% 24% 49% 14% 1	453
	21st to end	Night	5% 2 24% 48% 21%	657
August	1st to 10th	Night	5% 4 25% 47% 18% 1	597
	11th to 20th	Night	6% 4 21% 47% 21% 1	594
	21st to end	Night	9% 5% 19% 43% 23%	660
September	1st to 10th	Night	8% 4 18% 45% 24% 1	600
	11th to 20th	Night	12% 5% 23% 39% 20% 1	600
	21st to end	Night	13% 6% 19% 39% 21% 2	790
October	1st to 10th	Night	14% 7% 22% 37% 19% 2	800
	11th to 20th	Night	14% 11% 24% 37% 14% 1	800
	21st to end	Night	12% 10% 33% 33% 10% 1	980
November	1st to 10th	Night	15% 8% 31% 36% 9%	1025
	11th to 20th	Night	11% 12% 33% 31% 12% 1	1050
	21st to end	Night	10% 9% 32% 41% 8%	1050
December	1st to 10th	Night	12% 9% 30% 34% 15% 1	1050
	11th to 20th	Night	10% 9% 31% 38% 10% 1	1050
	21st to end	Night	12% 8% 30% 36% 13% 1	1155

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