Buffalo
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Buffalo clear sky chart from 2005-11-06 to 2024-11-05.

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	8% 6% 2 6% 4 4 4 4 6% 7% 49%	105313
	Night	7% 7% 3 6% 4 4 4 4 6% 7% 48%	102418
Transparency	Day	32% 6% 14% 28% 17% 3	105059
	Night	34% 6% 14% 27% 16% 3	102262
Seeing	Day	12% 8% 29% 30% 16% 4	16002
	Night	11% 8% 32% 37% 11% 1	25965

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	3 7% 3 8% 5% 5% 6% 5% 6% 7% 44%	2538
	11th to 20th	Day	1 8% 5% 9% 5% 5% 5% 4 5% 10% 41%	2540
	21st to end	Day	2 7% 4 9% 5% 4 4 3 4 7% 51%	2794
February	1st to 10th	Day	9% 10% 4 10% 6% 5% 5% 5% 5% 6% 34%	1657
	11th to 20th	Day	5% 9% 5% 9% 6% 6% 5% 4 5% 7% 39%	1771
	21st to end	Day	3 9% 4 9% 6% 5% 5% 5% 6% 7% 41%	1570
March	1st to 10th	Day	3 9% 3 7% 4 4 4 3 6% 8% 48%	3130
	11th to 20th	Day	5% 6% 3 7% 4 3 5% 5% 6% 10% 47%	3266
	21st to end	Day	14% 16% 6% 10% 4 4 4 3 5% 6% 29%	4165
April	1st to 10th	Day	14% 8% 3 8% 4 4 4 4 6% 8% 38%	2280
	11th to 20th	Day	13% 10% 4 9% 5% 4 4 4 6% 7% 33%	2251
	21st to end	Day	14% 9% 3 6% 4 4 5% 4 6% 6% 40%	2443
May	1st to 10th	Day	16% 8% 3 6% 5% 4 4 4 6% 7% 37%	4328
	11th to 20th	Day	10% 5% 2 6% 4 4 5% 4 7% 8% 46%	4388
	21st to end	Day	12% 6% 2 6% 4 4 5% 4 6% 8% 42%	4825
June	1st to 10th	Day	12% 5% 2 5% 4 3 5% 5% 6% 8% 45%	2660
	11th to 20th	Day	8% 5% 2 5% 4 5% 4 5% 8% 8% 46%	2660
	21st to end	Day	5% 3 1 4 3 4 4 4 6% 7% 58%	2660
July	1st to 10th	Day	5% 3 1 4 4 4 5% 5% 7% 9% 53%	4430
	11th to 20th	Day	2 2 1 3 2 2 3 3 5% 7% 69%	4430
	21st to end	Day	3 3 1 4 3 3 4 4 6% 9% 60%	4802
August	1st to 10th	Day	7% 4 1 5% 3 4 4 4 5% 7% 57%	4411
	11th to 20th	Day	8% 4 2 5% 4 4 4 4 6% 8% 51%	4018
	21st to end	Day	5% 3 1 3 2 3 3 3 5% 7% 65%	4180
September	1st to 10th	Day	6% 4 1 4 3 3 3 3 4 6% 63%	2280
	11th to 20th	Day	7% 4 1 4 3 3 4 3 6% 8% 58%	2210
	21st to end	Day	12% 4 1 4 3 2 2 3 4 6% 58%	2090
October	1st to 10th	Day	10% 4 1 3 2 2 2 2 4 6% 62%	3276
	11th to 20th	Day	9% 5% 2 4 2 3 3 2 5% 6% 59%	3061
	21st to end	Day	9% 6% 2 6% 4 3 4 4 5% 7% 48%	3091
November	1st to 10th	Day	7% 8% 3 5% 4 3 5% 4 6% 7% 49%	1709
	11th to 20th	Day	5% 8% 2 6% 4 4 5% 4 6% 8% 48%	1639
	21st to end	Day	5% 8% 4 6% 5% 4 5% 5% 6% 8% 45%	1520
December	1st to 10th	Day	5% 9% 4 10% 6% 5% 5% 3 6% 7% 40%	1520
	11th to 20th	Day	3 6% 3 8% 5% 4 4 4 7% 9% 47%	1926
	21st to end	Day	6% 9% 3 8% 5% 4 4 3 4 6% 47%	2794
January	1st to 10th	Night	3 9% 3 9% 7% 5% 5% 4 6% 6% 42%	4417
	11th to 20th	Night	3 9% 3 7% 5% 5% 8% 6% 7% 8% 39%	4430
	21st to end	Night	2 7% 4 9% 5% 5% 4 4 6% 8% 47%	4873
February	1st to 10th	Night	6% 11% 4 10% 5% 5% 5% 4 6% 7% 36%	2537
	11th to 20th	Night	4 11% 3 9% 6% 5% 4 4 6% 7% 41%	2296
	21st to end	Night	5% 9% 3 8% 5% 5% 5% 4 6% 6% 43%	1884
March	1st to 10th	Night	5% 9% 3 7% 5% 4 3 3 5% 8% 48%	3734
	11th to 20th	Night	5% 6% 2 6% 5% 4 4 4 7% 10% 48%	3702
	21st to end	Night	14% 14% 5% 9% 6% 4 5% 4 5% 6% 29%	3477
April	1st to 10th	Night	13% 10% 3 6% 4 3 4 5% 5% 6% 42%	1900
	11th to 20th	Night	11% 9% 4 7% 4 4 4 4 6% 7% 40%	1877
	21st to end	Night	13% 6% 2 6% 4 4 4 4 6% 8% 42%	1735
May	1st to 10th	Night	15% 8% 2 5% 4 4 4 3 5% 7% 44%	2638
	11th to 20th	Night	10% 6% 2 6% 5% 5% 5% 5% 8% 9% 40%	2517
	21st to end	Night	13% 6% 2 5% 5% 4 3 4 7% 9% 41%	2762
June	1st to 10th	Night	9% 4 2 5% 4 4 4 4 6% 9% 49%	1520
	11th to 20th	Night	11% 5% 1 6% 4 4 5% 5% 7% 7% 45%	1520
	21st to end	Night	6% 3 1 4 3 3 3 3 5% 9% 59%	1520
July	1st to 10th	Night	5% 3 1 4 3 4 4 4 6% 9% 56%	2540
	11th to 20th	Night	4 2 1 4 3 3 3 4 5% 9% 62%	2540
	21st to end	Night	3 3 2 4 4 3 4 3 6% 8% 60%	2761
August	1st to 10th	Night	5% 5% 2 5% 4 4 3 4 5% 6% 59%	2528
	11th to 20th	Night	6% 4 1 5% 3 4 5% 4 7% 9% 50%	2804
	21st to end	Night	5% 3 1 3 3 3 4 3 6% 8% 60%	3487
September	1st to 10th	Night	7% 4 1 3 2 3 3 2 4 7% 63%	1900
	11th to 20th	Night	8% 4 1 4 3 3 3 3 5% 7% 57%	1968
	21st to end	Night	10% 4 1 4 3 3 3 3 4 6% 58%	2090
October	1st to 10th	Night	8% 4 1 3 2 2 3 2 4 5% 65%	3689
	11th to 20th	Night	8% 5% 2 5% 3 3 3 3 5% 7% 55%	3835
	21st to end	Night	8% 8% 2 7% 4 4 3 3 4 7% 51%	4467
November	1st to 10th	Night	7% 7% 3 6% 4 4 4 4 5% 7% 47%	2470
	11th to 20th	Night	5% 9% 3 8% 4 5% 4 4 6% 6% 47%	2536
	21st to end	Night	5% 7% 3 5% 4 4 5% 5% 6% 9% 48%	2660
December	1st to 10th	Night	5% 9% 4 9% 7% 4 5% 4 5% 7% 42%	2660
	11th to 20th	Night	4 6% 3 8% 5% 5% 4 4 6% 7% 47%	3271
	21st to end	Night	8% 10% 3 8% 5% 4 4 4 5% 6% 44%	4873

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	36% 8% 19% 28% 8%	2539
	11th to 20th	Day	38% 9% 18% 21% 12% 2	2540
	21st to end	Day	34% 6% 19% 28% 12% 1	2794
February	1st to 10th	Day	48% 6% 12% 20% 12% 1	1657
	11th to 20th	Day	43% 6% 16% 22% 11% 2	1780
	21st to end	Day	40% 6% 16% 25% 11% 2	1570
March	1st to 10th	Day	33% 5% 13% 29% 18% 1	3130
	11th to 20th	Day	31% 7% 19% 32% 10% 1	3266
	21st to end	Day	55% 7% 15% 16% 7% 1	4165
April	1st to 10th	Day	43% 6% 15% 23% 11% 2	2280
	11th to 20th	Day	48% 6% 14% 23% 9% 1	2254
	21st to end	Day	44% 6% 14% 26% 10% 1	2443
May	1st to 10th	Day	43% 8% 12% 24% 12% 2	4328
	11th to 20th	Day	33% 8% 12% 33% 13% 1	4392
	21st to end	Day	37% 9% 16% 31% 7%	4825
June	1st to 10th	Day	34% 8% 19% 27% 10% 1	2660
	11th to 20th	Day	32% 8% 16% 29% 14% 2	2660
	21st to end	Day	23% 6% 15% 31% 20% 4	2660
July	1st to 10th	Day	24% 7% 16% 32% 19% 3	4361
	11th to 20th	Day	15% 4 10% 34% 28% 9%	4355
	21st to end	Day	20% 5% 11% 27% 31% 7%	4651
August	1st to 10th	Day	27% 5% 10% 29% 19% 11%	4396
	11th to 20th	Day	30% 6% 13% 30% 17% 3	4060
	21st to end	Day	20% 4 10% 28% 33% 6%	4179
September	1st to 10th	Day	23% 4 8% 31% 26% 8%	2280
	11th to 20th	Day	24% 5% 12% 31% 23% 5%	2210
	21st to end	Day	28% 4 9% 33% 23% 3	2090
October	1st to 10th	Day	25% 3 8% 25% 28% 11%	3276
	11th to 20th	Day	27% 3 11% 33% 23% 2	3061
	21st to end	Day	35% 4 12% 30% 16% 3	3091
November	1st to 10th	Day	34% 5% 13% 27% 17% 3	1709
	11th to 20th	Day	33% 5% 15% 28% 17% 2	1639
	21st to end	Day	34% 7% 16% 29% 12% 2	1520
December	1st to 10th	Day	41% 5% 15% 27% 11% 1	1520
	11th to 20th	Day	32% 6% 19% 35% 7% 1	1924
	21st to end	Day	39% 3 9% 31% 16% 2	2794
January	1st to 10th	Night	41% 6% 13% 28% 11% 1	4417
	11th to 20th	Night	39% 8% 17% 23% 11% 2	4430
	21st to end	Night	34% 6% 20% 26% 13% 1	4873
February	1st to 10th	Night	45% 6% 16% 20% 13% 1	2537
	11th to 20th	Night	41% 5% 16% 25% 11% 1	2297
	21st to end	Night	39% 6% 13% 24% 15% 2	1884
March	1st to 10th	Night	34% 6% 11% 31% 17% 1	3734
	11th to 20th	Night	30% 6% 21% 27% 15% 1	3702
	21st to end	Night	53% 8% 14% 19% 5%	3477
April	1st to 10th	Night	42% 5% 14% 25% 12% 2	1900
	11th to 20th	Night	42% 6% 13% 25% 13% 1	1877
	21st to end	Night	39% 6% 14% 29% 12% 1	1735
May	1st to 10th	Night	39% 7% 13% 26% 14% 2	2638
	11th to 20th	Night	35% 10% 16% 31% 7%	2518
	21st to end	Night	36% 9% 16% 31% 8%	2762
June	1st to 10th	Night	31% 8% 18% 29% 13% 1	1520
	11th to 20th	Night	34% 8% 18% 23% 15% 2	1520
	21st to end	Night	22% 6% 18% 31% 19% 3	1520
July	1st to 10th	Night	23% 6% 18% 31% 21% 2	2500
	11th to 20th	Night	19% 4 12% 30% 28% 7%	2492
	21st to end	Night	22% 5% 12% 30% 24% 7%	2674
August	1st to 10th	Night	26% 5% 9% 30% 20% 10%	2520
	11th to 20th	Night	28% 6% 21% 24% 18% 4	2828
	21st to end	Night	21% 6% 10% 30% 27% 6%	3487
September	1st to 10th	Night	22% 3 9% 30% 26% 9%	1900
	11th to 20th	Night	27% 4 12% 29% 22% 5%	1968
	21st to end	Night	29% 4 10% 30% 25% 4	2090
October	1st to 10th	Night	23% 3 8% 25% 26% 14%	3689
	11th to 20th	Night	30% 3 8% 34% 22% 2	3835
	21st to end	Night	35% 3 11% 26% 18% 6%	4467
November	1st to 10th	Night	35% 6% 14% 25% 16% 4	2470
	11th to 20th	Night	36% 6% 12% 27% 16% 3	2536
	21st to end	Night	32% 6% 18% 26% 16% 2	2660
December	1st to 10th	Night	41% 5% 15% 25% 13% 2	2660
	11th to 20th	Night	34% 7% 17% 32% 10%	3272
	21st to end	Night	41% 4 10% 29% 15% 2	4873

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	7% 10% 35% 28% 12% 7%	270
	11th to 20th	Day	12% 13% 37% 23% 13% 2	270
	21st to end	Day	11% 17% 36% 26% 9% 1	297
February	1st to 10th	Day	13% 11% 39% 31% 5%	270
	11th to 20th	Day	15% 10% 43% 26% 6% 1	270
	21st to end	Day	12% 11% 36% 32% 7% 2	225
March	1st to 10th	Day	13% 11% 40% 23% 11% 3	270
	11th to 20th	Day	12% 10% 33% 31% 10% 5%	310
	21st to end	Day	19% 12% 28% 24% 12% 4	506
April	1st to 10th	Day	20% 15% 30% 28% 7%	460
	11th to 20th	Day	21% 16% 37% 19% 6% 1	452
	21st to end	Day	19% 10% 25% 28% 15% 3	623
May	1st to 10th	Day	19% 8% 27% 26% 15% 5%	653
	11th to 20th	Day	19% 6% 22% 31% 16% 5%	675
	21st to end	Day	17% 7% 27% 29% 15% 5%	734
June	1st to 10th	Day	11% 8% 22% 29% 24% 5%	680
	11th to 20th	Day	10% 8% 35% 30% 14% 2	680
	21st to end	Day	8% 6% 26% 34% 21% 4	680
July	1st to 10th	Day	6% 3 20% 38% 27% 6%	671
	11th to 20th	Day	3 5% 27% 39% 24% 3	668
	21st to end	Day	6% 3 22% 40% 23% 6%	739
August	1st to 10th	Day	8% 4 21% 39% 23% 5%	676
	11th to 20th	Day	8% 3 21% 36% 25% 6%	585
	21st to end	Day	5% 7% 24% 33% 21% 9%	539
September	1st to 10th	Day	6% 6% 28% 33% 19% 7%	490
	11th to 20th	Day	8% 3 27% 33% 23% 6%	420
	21st to end	Day	16% 9% 23% 26% 20% 6%	300
October	1st to 10th	Day	19% 8% 21% 24% 21% 7%	300
	11th to 20th	Day	14% 12% 33% 21% 16% 4	300
	21st to end	Day	16% 14% 34% 18% 13% 4	330
November	1st to 10th	Day	14% 11% 34% 26% 9% 5%	282
	11th to 20th	Day	10% 13% 40% 25% 9% 3	270
	21st to end	Day	13% 10% 37% 26% 13% 1	270
December	1st to 10th	Day	12% 13% 36% 24% 12% 2	270
	11th to 20th	Day	10% 13% 40% 30% 7% 1	270
	21st to end	Day	11% 10% 42% 26% 9% 2	297
January	1st to 10th	Night	7% 12% 40% 29% 11% 1	950
	11th to 20th	Night	10% 14% 39% 27% 9% 1	950
	21st to end	Night	9% 14% 36% 32% 8%	1045
February	1st to 10th	Night	9% 10% 39% 33% 10%	827
	11th to 20th	Night	9% 12% 39% 33% 6% 1	744
	21st to end	Night	9% 6% 36% 38% 11% 1	628
March	1st to 10th	Night	11% 9% 36% 35% 9% 1	760
	11th to 20th	Night	10% 6% 36% 36% 10% 2	754
	21st to end	Night	15% 8% 28% 39% 9% 1	627
April	1st to 10th	Night	18% 9% 30% 36% 7%	570
	11th to 20th	Night	14% 10% 38% 32% 6%	563
	21st to end	Night	16% 8% 24% 37% 14%	570
May	1st to 10th	Night	14% 6% 25% 39% 14% 2	570
	11th to 20th	Night	17% 6% 23% 38% 16% 1	561
	21st to end	Night	18% 4 30% 35% 13%	617
June	1st to 10th	Night	11% 8% 26% 38% 16% 1	570
	11th to 20th	Night	13% 8% 36% 35% 8%	570
	21st to end	Night	7% 3 32% 44% 12% 1	570
July	1st to 10th	Night	6% 2 26% 48% 18% 1	555
	11th to 20th	Night	6% 4 28% 50% 12%	552
	21st to end	Night	4 3 23% 54% 16%	624
August	1st to 10th	Night	6% 3 25% 48% 16% 1	567
	11th to 20th	Night	7% 3 22% 47% 20% 1	564
	21st to end	Night	7% 3 25% 48% 16% 1	627
September	1st to 10th	Night	8% 3 23% 46% 20% 1	570
	11th to 20th	Night	10% 6% 24% 46% 14% 1	570
	21st to end	Night	11% 6% 29% 40% 14% 1	570
October	1st to 10th	Night	14% 7% 27% 36% 15%	688
	11th to 20th	Night	13% 7% 30% 34% 15% 1	792
	21st to end	Night	14% 10% 34% 31% 9% 2	1045
November	1st to 10th	Night	10% 10% 34% 34% 11% 1	950
	11th to 20th	Night	9% 11% 37% 33% 9% 1	950
	21st to end	Night	9% 13% 37% 32% 10%	950
December	1st to 10th	Night	9% 11% 40% 29% 10%	950
	11th to 20th	Night	9% 11% 37% 34% 8% 1	950
	21st to end	Night	13% 12% 36% 30% 8% 1	1045

Page generated at 2024-11-03 00:11:13. Version ac07

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