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 2025-02-21.

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	16% 12% 4 9% 5% 5% 4 4 5% 7% 30%	108759
	Night	17% 13% 4 10% 5% 5% 4 3 5% 6% 27%	109798
Transparency	Day	53% 4 12% 19% 10% 1	112397
	Night	57% 4 11% 18% 9% 1	114323
Seeing	Day	23% 17% 28% 19% 9% 3	14797
	Night	24% 15% 27% 24% 10% 1	24354

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
Month	Days in Month		Occurrence of each Forecast	Data Points
January	1st to 10th	Day	14% 23% 7% 16% 8% 6% 4 3 4 4 11%	3597
	11th to 20th	Day	12% 22% 8% 20% 11% 5% 4 3 3 3 8%	3916
	21st to end	Day	19% 16% 7% 15% 8% 8% 6% 3 4 3 11%	4466
February	1st to 10th	Day	17% 19% 5% 14% 8% 6% 5% 3 4 5% 13%	1800
	11th to 20th	Day	14% 19% 6% 16% 8% 6% 5% 2 4 5% 16%	1753
	21st to end	Day	21% 15% 5% 12% 8% 4 4 4 4 5% 17%	1485
March	1st to 10th	Day	19% 13% 5% 9% 5% 4 4 3 4 5% 29%	3432
	11th to 20th	Day	11% 20% 5% 8% 5% 5% 4 4 5% 6% 28%	3480
	21st to end	Day	17% 12% 4 9% 5% 4 4 3 5% 6% 29%	3815
April	1st to 10th	Day	18% 16% 4 7% 4 4 4 3 4 5% 30%	2262
	11th to 20th	Day	19% 10% 3 7% 4 4 4 4 5% 5% 35%	2268
	21st to end	Day	21% 10% 3 7% 4 4 4 4 4 5% 33%	2470
May	1st to 10th	Day	21% 9% 3 7% 5% 4 4 3 5% 7% 32%	4108
	11th to 20th	Day	15% 10% 3 9% 5% 5% 5% 4 6% 8% 29%	4382
	21st to end	Day	13% 7% 2 6% 3 4 3 4 6% 7% 45%	4837
June	1st to 10th	Day	16% 6% 2 6% 4 5% 5% 4 6% 7% 37%	2660
	11th to 20th	Day	13% 5% 3 6% 5% 5% 4 5% 7% 9% 39%	2660
	21st to end	Day	15% 6% 2 5% 4 4 4 4 6% 8% 42%	2660
July	1st to 10th	Day	10% 5% 2 6% 4 4 5% 4 7% 9% 45%	4440
	11th to 20th	Day	13% 6% 2 6% 4 5% 4 4 7% 9% 40%	4440
	21st to end	Day	7% 6% 2 6% 4 5% 6% 5% 7% 10% 41%	4500
August	1st to 10th	Day	18% 6% 2 5% 4 4 4 4 5% 9% 37%	4104
	11th to 20th	Day	13% 6% 3 7% 5% 5% 6% 5% 8% 10% 33%	4044
	21st to end	Day	12% 5% 2 6% 4 4 4 4 6% 9% 44%	4286
September	1st to 10th	Day	15% 7% 2 6% 4 5% 5% 3 6% 6% 41%	2280
	11th to 20th	Day	12% 5% 2 6% 3 5% 4 4 6% 8% 45%	2203
	21st to end	Day	16% 8% 3 7% 5% 6% 5% 4 6% 7% 32%	2028
October	1st to 10th	Day	21% 7% 3 7% 4 4 5% 3 5% 8% 33%	1900
	11th to 20th	Day	21% 10% 3 8% 5% 4 5% 4 6% 6% 28%	1900
	21st to end	Day	26% 13% 4 9% 5% 5% 4 4 4 5% 22%	2090
November	1st to 10th	Day	15% 11% 4 8% 6% 6% 4 3 4 6% 32%	1747
	11th to 20th	Day	15% 15% 5% 9% 5% 6% 4 4 5% 6% 27%	1600
	21st to end	Day	21% 17% 4 9% 7% 5% 4 3 5% 6% 18%	1600
December	1st to 10th	Day	21% 18% 5% 12% 6% 6% 5% 5% 5% 6% 12%	2600
	11th to 20th	Day	23% 20% 5% 10% 5% 4 3 3 4 4 17%	2986
	21st to end	Day	23% 22% 6% 12% 6% 5% 4 3 3 4 11%	3960
January	1st to 10th	Night	17% 19% 6% 13% 7% 5% 4 3 4 5% 16%	6349
	11th to 20th	Night	11% 19% 8% 21% 11% 8% 4 3 4 3 8%	5951
	21st to end	Night	20% 19% 7% 16% 7% 6% 5% 3 4 3 9%	6490
February	1st to 10th	Night	19% 19% 6% 13% 6% 5% 4 3 4 4 17%	2600
	11th to 20th	Night	16% 16% 6% 12% 7% 5% 5% 4 4 5% 19%	2533
	21st to end	Night	19% 16% 5% 13% 7% 4 4 3 5% 5% 19%	1966
March	1st to 10th	Night	21% 13% 4 8% 5% 3 3 3 3 5% 31%	3408
	11th to 20th	Night	20% 17% 3 8% 5% 4 4 3 4 6% 26%	3479
	21st to end	Night	17% 10% 3 7% 4 4 4 3 5% 5% 39%	3817
April	1st to 10th	Night	22% 12% 4 7% 5% 4 4 3 5% 4 30%	1916
	11th to 20th	Night	19% 9% 3 8% 4 4 4 4 4 6% 34%	1875
	21st to end	Night	19% 9% 4 6% 4 4 5% 4 4 7% 35%	1712
May	1st to 10th	Night	24% 10% 3 7% 5% 3 3 3 5% 6% 32%	2833
	11th to 20th	Night	14% 7% 3 7% 6% 6% 5% 4 6% 9% 33%	2509
	21st to end	Night	13% 6% 2 6% 3 3 4 4 6% 8% 45%	2738
June	1st to 10th	Night	13% 7% 3 7% 6% 6% 6% 5% 5% 8% 36%	1520
	11th to 20th	Night	13% 5% 2 5% 5% 5% 6% 4 6% 8% 41%	1520
	21st to end	Night	16% 6% 2 6% 4 4 5% 3 6% 7% 40%	1520
July	1st to 10th	Night	9% 7% 3 7% 5% 4 4 4 6% 9% 42%	2520
	11th to 20th	Night	12% 6% 2 6% 4 4 3 3 6% 8% 44%	2520
	21st to end	Night	10% 5% 2 5% 4 5% 5% 4 7% 7% 46%	3049
August	1st to 10th	Night	11% 8% 2 7% 5% 4 4 3 6% 9% 40%	2825
	11th to 20th	Night	16% 7% 2 7% 4 5% 5% 4 6% 7% 37%	2785
	21st to end	Night	9% 4 2 5% 5% 5% 5% 4 7% 9% 45%	3338
September	1st to 10th	Night	14% 7% 2 5% 4 3 4 3 5% 8% 44%	1900
	11th to 20th	Night	13% 5% 2 5% 4 3 3 3 4 8% 51%	1974
	21st to end	Night	17% 8% 2 6% 5% 4 5% 5% 6% 7% 36%	2152
October	1st to 10th	Night	18% 6% 3 7% 5% 4 4 3 4 7% 38%	2280
	11th to 20th	Night	22% 10% 3 7% 4 5% 5% 3 5% 6% 30%	2280
	21st to end	Night	27% 9% 3 6% 5% 5% 4 4 5% 6% 26%	2508
November	1st to 10th	Night	18% 9% 3 7% 4 4 4 3 5% 6% 37%	2547
	11th to 20th	Night	16% 13% 4 9% 6% 5% 5% 3 5% 6% 28%	2800
	21st to end	Night	19% 16% 4 9% 5% 5% 5% 5% 5% 5% 22%	2800
December	1st to 10th	Night	19% 21% 7% 13% 6% 5% 5% 3 5% 5% 12%	4580
	11th to 20th	Night	21% 22% 5% 10% 6% 5% 4 3 4 4 17%	5208
	21st to end	Night	25% 18% 6% 11% 6% 5% 5% 3 4 4 13%	6996

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	80% 3 6% 8% 3	3598
	11th to 20th	Day	82% 3 6% 5% 4 1	3950
	21st to end	Day	80% 2 11% 4 3	4466
February	1st to 10th	Day	74% 5% 9% 10% 2	1800
	11th to 20th	Day	73% 4 8% 12% 3	1762
	21st to end	Day	69% 5% 11% 10% 5%	1485
March	1st to 10th	Day	58% 4 11% 21% 6%	3435
	11th to 20th	Day	56% 4 19% 14% 6% 1	3480
	21st to end	Day	55% 6% 8% 23% 7% 1	3815
April	1st to 10th	Day	56% 4 11% 19% 9% 1	2262
	11th to 20th	Day	51% 4 10% 20% 13% 2	2268
	21st to end	Day	53% 4 9% 18% 12% 2	2470
May	1st to 10th	Day	52% 5% 11% 19% 12% 2	4120
	11th to 20th	Day	52% 5% 14% 20% 7% 1	4386
	21st to end	Day	37% 4 13% 27% 15% 3	4837
June	1st to 10th	Day	43% 6% 13% 20% 15% 2	2660
	11th to 20th	Day	41% 6% 15% 24% 14% 1	2660
	21st to end	Day	40% 5% 14% 25% 14% 1	2660
July	1st to 10th	Day	36% 4 13% 28% 18% 2	4370
	11th to 20th	Day	40% 4 13% 28% 14%	4365
	21st to end	Day	37% 5% 19% 22% 16% 1	4356
August	1st to 10th	Day	45% 5% 14% 23% 13% 1	4091
	11th to 20th	Day	45% 5% 16% 25% 9% 1	4083
	21st to end	Day	37% 4 12% 34% 12% 1	4286
September	1st to 10th	Day	41% 7% 13% 26% 12% 1	2280
	11th to 20th	Day	37% 5% 14% 29% 15% 1	2203
	21st to end	Day	49% 6% 14% 22% 9% 1	2028
October	1st to 10th	Day	42% 3 13% 27% 14% 1	3160
	11th to 20th	Day	47% 3 16% 21% 12% 1	3140
	21st to end	Day	53% 2 15% 23% 7%	3428
November	1st to 10th	Day	53% 6% 11% 19% 9% 1	1747
	11th to 20th	Day	57% 6% 15% 15% 7% 1	1600
	21st to end	Day	66% 5% 13% 12% 4	1600
December	1st to 10th	Day	73% 3 16% 7% 1	2600
	11th to 20th	Day	70% 3 10% 10% 7%	2986
	21st to end	Day	79% 2 9% 7% 3	3960
January	1st to 10th	Night	73% 3 8% 12% 3	6349
	11th to 20th	Night	79% 5% 6% 6% 4	5992
	21st to end	Night	80% 2 8% 6% 4	6490
February	1st to 10th	Night	71% 5% 9% 12% 4	2600
	11th to 20th	Night	66% 5% 11% 14% 4	2535
	21st to end	Night	67% 4 10% 13% 6%	1966
March	1st to 10th	Night	58% 3 11% 22% 6%	3418
	11th to 20th	Night	59% 4 13% 15% 7% 1	3480
	21st to end	Night	45% 5% 8% 25% 15% 1	3817
April	1st to 10th	Night	57% 5% 8% 19% 11% 1	1916
	11th to 20th	Night	50% 5% 10% 19% 14% 2	1875
	21st to end	Night	49% 5% 11% 19% 14% 2	1712
May	1st to 10th	Night	53% 5% 10% 18% 11% 3	2840
	11th to 20th	Night	47% 6% 16% 21% 9% 1	2510
	21st to end	Night	37% 5% 12% 24% 20% 2	2739
June	1st to 10th	Night	45% 7% 10% 22% 16% 1	1520
	11th to 20th	Night	39% 6% 12% 23% 19% 2	1520
	21st to end	Night	42% 6% 13% 23% 15% 2	1520
July	1st to 10th	Night	40% 4 11% 24% 19% 3	2480
	11th to 20th	Night	38% 3 14% 30% 13% 1	2472
	21st to end	Night	36% 5% 16% 24% 17% 2	2952
August	1st to 10th	Night	40% 4 15% 27% 13% 1	2814
	11th to 20th	Night	45% 4 14% 27% 10%	2812
	21st to end	Night	36% 4 12% 33% 14% 1	3338
September	1st to 10th	Night	38% 5% 14% 27% 15% 2	1900
	11th to 20th	Night	34% 4 12% 30% 19% 1	1974
	21st to end	Night	46% 6% 13% 22% 13% 1	2152
October	1st to 10th	Night	44% 3 8% 26% 18% 1	3800
	11th to 20th	Night	50% 3 13% 21% 13% 1	3779
	21st to end	Night	48% 3 16% 25% 8% 1	4120
November	1st to 10th	Night	48% 6% 10% 23% 11% 2	2547
	11th to 20th	Night	57% 5% 13% 17% 8% 1	2800
	21st to end	Night	62% 6% 14% 15% 3	2800
December	1st to 10th	Night	74% 3 13% 8% 2	4580
	11th to 20th	Night	70% 3 7% 11% 8% 1	5208
	21st to end	Night	75% 3 10% 9% 3	6996

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	27% 30% 27% 12% 5% 2	200
	11th to 20th	Day	27% 29% 28% 11% 4 1	277
	21st to end	Day	27% 25% 27% 17% 4	330
February	1st to 10th	Day	33% 26% 27% 11% 2	300
	11th to 20th	Day	32% 32% 26% 8% 1	300
	21st to end	Day	39% 19% 29% 11% 1	282
March	1st to 10th	Day	26% 21% 31% 16% 5% 1	460
	11th to 20th	Day	31% 17% 33% 15% 4 1	460
	21st to end	Day	31% 20% 25% 17% 5% 2	506
April	1st to 10th	Day	25% 23% 28% 17% 6% 1	460
	11th to 20th	Day	31% 21% 22% 15% 7% 3	452
	21st to end	Day	30% 17% 29% 16% 7% 2	460
May	1st to 10th	Day	27% 15% 29% 17% 8% 4	463
	11th to 20th	Day	20% 14% 31% 21% 11% 3	487
	21st to end	Day	17% 13% 31% 23% 10% 5%	529
June	1st to 10th	Day	23% 14% 32% 22% 8% 1	490
	11th to 20th	Day	15% 16% 30% 25% 10% 3	490
	21st to end	Day	21% 15% 30% 24% 8% 2	490
July	1st to 10th	Day	11% 10% 27% 31% 18% 4	485
	11th to 20th	Day	16% 12% 29% 25% 13% 5%	484
	21st to end	Day	11% 9% 34% 28% 12% 5%	532
August	1st to 10th	Day	16% 9% 24% 28% 15% 8%	486
	11th to 20th	Day	13% 9% 28% 26% 16% 8%	479
	21st to end	Day	14% 8% 31% 24% 15% 7%	539
September	1st to 10th	Day	16% 13% 23% 24% 16% 8%	490
	11th to 20th	Day	12% 7% 21% 24% 23% 13%	490
	21st to end	Day	20% 15% 27% 21% 12% 6%	490
October	1st to 10th	Day	26% 12% 25% 19% 13% 5%	490
	11th to 20th	Day	26% 21% 28% 18% 6% 2	490
	21st to end	Day	35% 19% 24% 15% 6%	539
November	1st to 10th	Day	26% 20% 30% 16% 7% 1	347
	11th to 20th	Day	33% 25% 28% 10% 3 3	200
	21st to end	Day	34% 30% 25% 10% 3	200
December	1st to 10th	Day	33% 24% 30% 9% 4 1	200
	11th to 20th	Day	34% 26% 24% 14% 2	200
	21st to end	Day	34% 29% 22% 11% 3 1	220
January	1st to 10th	Night	31% 25% 27% 13% 4	800
	11th to 20th	Night	32% 24% 26% 15% 3	800
	21st to end	Night	26% 22% 31% 16% 5%	880
February	1st to 10th	Night	28% 26% 28% 15% 2	800
	11th to 20th	Night	27% 24% 30% 17% 3	783
	21st to end	Night	29% 23% 28% 17% 2	629
March	1st to 10th	Night	24% 18% 30% 22% 6%	760
	11th to 20th	Night	28% 17% 30% 20% 5% 1	760
	21st to end	Night	24% 14% 31% 22% 7% 1	836
April	1st to 10th	Night	26% 16% 32% 22% 3	760
	11th to 20th	Night	24% 16% 29% 23% 7% 1	751
	21st to end	Night	24% 9% 30% 28% 8%	572
May	1st to 10th	Night	22% 11% 22% 31% 12% 2	570
	11th to 20th	Night	16% 7% 30% 37% 9%	388
	21st to end	Night	14% 10% 25% 34% 16% 1	411
June	1st to 10th	Night	14% 8% 32% 32% 13% 1	380
	11th to 20th	Night	14% 9% 27% 36% 12%	380
	21st to end	Night	18% 7% 32% 32% 11%	380
July	1st to 10th	Night	10% 6% 25% 41% 17% 1	370
	11th to 20th	Night	13% 7% 29% 33% 18% 1	368
	21st to end	Night	13% 4 25% 39% 17% 2	599
August	1st to 10th	Night	12% 4 20% 40% 22% 2	567
	11th to 20th	Night	11% 6% 21% 34% 26% 3	564
	21st to end	Night	13% 5% 24% 32% 24% 2	750
September	1st to 10th	Night	17% 8% 21% 33% 18% 3	760
	11th to 20th	Night	14% 5% 22% 29% 26% 5%	760
	21st to end	Night	20% 10% 24% 27% 16% 4	760
October	1st to 10th	Night	20% 11% 27% 25% 16% 2	760
	11th to 20th	Night	28% 16% 24% 23% 8% 1	760
	21st to end	Night	33% 15% 26% 22% 4	836
November	1st to 10th	Night	24% 16% 27% 24% 9% 1	780
	11th to 20th	Night	25% 21% 28% 17% 8% 1	800
	21st to end	Night	28% 22% 28% 16% 5%	800
December	1st to 10th	Night	35% 23% 23% 15% 4	800
	11th to 20th	Night	31% 26% 24% 16% 3	800
	21st to end	Night	34% 20% 27% 17% 2	880

Page generated at 2025-02-18 03:26:31. Version ac07

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