Niagara Falls
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Niagara Falls clear sky chart from 2005-11-06 to 2024-08-15.

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	15% 11% 3 8% 5% 5% 5% 4 5% 7% 32%	95554
	Night	16% 11% 4 8% 5% 4 4 4 5% 6% 31%	93148
Transparency	Day	49% 9% 13% 18% 9% 1	95282
	Night	52% 9% 13% 16% 9% 1	92974
Seeing	Day	20% 11% 26% 24% 14% 5%	14187
	Night	22% 11% 27% 27% 12% 2	23585

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	16% 20% 6% 13% 6% 5% 4 3 4 5% 18%	2517
	11th to 20th	Day	12% 23% 7% 18% 10% 5% 4 3 4 4 10%	2776
	21st to end	Day	23% 19% 8% 12% 8% 6% 4 3 3 4 11%	3124
February	1st to 10th	Day	18% 18% 4 13% 7% 6% 4 4 5% 5% 15%	1710
	11th to 20th	Day	13% 19% 6% 16% 8% 5% 5% 4 4 4 18%	1663
	21st to end	Day	19% 15% 4 12% 8% 4 4 3 5% 5% 19%	1480
March	1st to 10th	Day	19% 12% 5% 10% 5% 4 4 3 5% 4 29%	3432
	11th to 20th	Day	10% 20% 4 8% 5% 5% 4 3 5% 6% 29%	3480
	21st to end	Day	17% 10% 3 8% 5% 4 4 4 5% 6% 33%	3815
April	1st to 10th	Day	18% 14% 3 8% 5% 4 4 2 4 5% 32%	2255
	11th to 20th	Day	20% 9% 3 6% 4 4 4 3 5% 6% 35%	2286
	21st to end	Day	19% 9% 3 8% 5% 4 4 4 4 6% 33%	2470
May	1st to 10th	Day	18% 9% 3 8% 4 5% 5% 3 5% 7% 33%	4108
	11th to 20th	Day	14% 10% 3 9% 5% 5% 4 4 6% 8% 30%	4363
	21st to end	Day	11% 6% 2 6% 4 3 4 3 6% 8% 46%	4837
June	1st to 10th	Day	14% 7% 2 6% 4 4 5% 3 6% 8% 39%	2660
	11th to 20th	Day	11% 6% 2 6% 5% 5% 5% 4 7% 9% 40%	2660
	21st to end	Day	14% 6% 2 5% 3 4 5% 4 7% 9% 42%	2660
July	1st to 10th	Day	8% 5% 2 5% 5% 4 5% 5% 7% 10% 44%	4440
	11th to 20th	Day	11% 6% 2 5% 5% 5% 5% 4 7% 10% 41%	4440
	21st to end	Day	8% 5% 2 6% 5% 5% 5% 4 7% 9% 43%	4482
August	1st to 10th	Day	10% 5% 2 6% 4 5% 5% 5% 8% 11% 40%	2457
	11th to 20th	Day	9% 5% 3 6% 5% 5% 7% 5% 8% 11% 37%	2357
	21st to end	Day	11% 6% 2 6% 3 4 4 4 6% 9% 44%	2452
September	1st to 10th	Day	14% 7% 2 5% 4 5% 4 4 7% 8% 41%	2160
	11th to 20th	Day	11% 6% 2 6% 4 5% 5% 4 6% 7% 45%	2075
	21st to end	Day	13% 8% 3 7% 5% 5% 5% 5% 7% 8% 34%	1931
October	1st to 10th	Day	20% 8% 2 7% 5% 4 5% 3 5% 7% 34%	1800
	11th to 20th	Day	20% 10% 3 9% 5% 5% 5% 4 5% 6% 29%	1800
	21st to end	Day	25% 14% 4 9% 6% 4 5% 3 4 5% 22%	1980
November	1st to 10th	Day	14% 10% 4 8% 6% 5% 5% 3 6% 6% 33%	1646
	11th to 20th	Day	16% 11% 4 7% 6% 5% 5% 4 5% 7% 30%	1520
	21st to end	Day	20% 15% 4 9% 6% 4 5% 3 5% 6% 23%	1520
December	1st to 10th	Day	18% 19% 5% 11% 7% 6% 4 4 5% 5% 17%	1520
	11th to 20th	Day	19% 17% 7% 12% 6% 4 5% 4 5% 6% 15%	1906
	21st to end	Day	26% 22% 6% 11% 5% 4 4 2 3 4 12%	2772
January	1st to 10th	Night	18% 19% 6% 11% 6% 5% 4 3 4 5% 20%	4429
	11th to 20th	Night	14% 19% 7% 16% 7% 5% 4 3 5% 4 16%	4182
	21st to end	Night	24% 19% 6% 12% 6% 5% 4 3 4 4 12%	4532
February	1st to 10th	Night	18% 17% 6% 12% 6% 5% 5% 3 5% 5% 20%	2470
	11th to 20th	Night	15% 15% 4 12% 6% 5% 6% 4 5% 5% 22%	2403
	21st to end	Night	18% 14% 4 13% 7% 6% 5% 4 5% 6% 21%	1968
March	1st to 10th	Night	21% 12% 4 8% 5% 5% 4 3 4 5% 31%	3408
	11th to 20th	Night	16% 15% 3 8% 4 4 4 3 5% 7% 30%	3479
	21st to end	Night	16% 8% 3 8% 4 3 4 3 5% 6% 41%	3817
April	1st to 10th	Night	20% 11% 4 9% 5% 4 4 3 4 6% 31%	1924
	11th to 20th	Night	18% 8% 3 7% 5% 4 4 4 6% 5% 36%	1859
	21st to end	Night	16% 9% 3 7% 5% 4 5% 5% 5% 6% 35%	1710
May	1st to 10th	Night	20% 10% 4 7% 4 4 3 3 4 6% 33%	2833
	11th to 20th	Night	12% 8% 3 7% 5% 5% 6% 5% 7% 8% 34%	2527
	21st to end	Night	11% 6% 2 5% 4 4 5% 4 6% 8% 46%	2738
June	1st to 10th	Night	11% 6% 2 9% 5% 6% 5% 5% 7% 7% 36%	1520
	11th to 20th	Night	9% 5% 2 6% 6% 5% 4 5% 7% 7% 43%	1520
	21st to end	Night	13% 6% 1 5% 5% 4 6% 4 6% 8% 41%	1520
July	1st to 10th	Night	7% 6% 2 7% 6% 4 4 4 6% 8% 45%	2520
	11th to 20th	Night	11% 5% 2 6% 4 3 4 4 6% 9% 47%	2520
	21st to end	Night	9% 4 2 6% 4 4 5% 4 7% 7% 48%	3054
August	1st to 10th	Night	8% 5% 2 6% 4 5% 5% 4 7% 9% 46%	1701
	11th to 20th	Night	7% 6% 2 6% 5% 4 5% 4 7% 8% 45%	1643
	21st to end	Night	8% 5% 2 7% 4 4 5% 5% 5% 8% 47%	1885
September	1st to 10th	Night	14% 7% 2 5% 4 5% 4 3 5% 7% 44%	1800
	11th to 20th	Night	13% 4 2 5% 3 3 4 3 6% 6% 52%	1881
	21st to end	Night	16% 6% 2 7% 5% 5% 5% 4 6% 7% 38%	2029
October	1st to 10th	Night	17% 7% 3 7% 4 4 4 3 5% 7% 37%	2160
	11th to 20th	Night	21% 10% 3 7% 5% 5% 4 3 5% 5% 30%	2160
	21st to end	Night	25% 9% 3 7% 6% 4 6% 3 4 5% 27%	2376
November	1st to 10th	Night	16% 10% 3 6% 4 4 4 3 5% 6% 39%	2428
	11th to 20th	Night	15% 11% 4 8% 6% 5% 5% 4 5% 7% 30%	2660
	21st to end	Night	18% 14% 4 9% 5% 5% 5% 4 5% 6% 24%	2660
December	1st to 10th	Night	21% 18% 5% 9% 6% 5% 4 4 5% 5% 18%	2660
	11th to 20th	Night	16% 19% 6% 11% 6% 5% 4 4 5% 5% 20%	3288
	21st to end	Night	29% 16% 5% 10% 6% 4 4 3 5% 5% 12%	4884

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	65% 11% 11% 9% 3	2518
	11th to 20th	Day	77% 10% 7% 5% 1	2776
	21st to end	Day	77% 8% 11% 3 1	3124
February	1st to 10th	Day	71% 8% 10% 10% 2	1710
	11th to 20th	Day	69% 9% 8% 11% 3	1672
	21st to end	Day	66% 8% 12% 10% 5%	1480
March	1st to 10th	Day	55% 8% 12% 19% 5%	3435
	11th to 20th	Day	51% 11% 16% 15% 7% 1	3480
	21st to end	Day	46% 9% 13% 23% 7% 1	3815
April	1st to 10th	Day	54% 6% 12% 18% 9% 1	2255
	11th to 20th	Day	48% 7% 11% 19% 13% 2	2286
	21st to end	Day	50% 7% 11% 17% 12% 2	2470
May	1st to 10th	Day	47% 8% 13% 18% 11% 2	4120
	11th to 20th	Day	47% 13% 14% 19% 7% 1	4367
	21st to end	Day	34% 9% 14% 25% 16% 3	4837
June	1st to 10th	Day	40% 9% 14% 20% 15% 2	2660
	11th to 20th	Day	39% 8% 15% 24% 14% 1	2660
	21st to end	Day	37% 9% 15% 24% 14% 1	2660
July	1st to 10th	Day	32% 9% 14% 27% 17% 2	4370
	11th to 20th	Day	33% 9% 15% 30% 12% 1	4365
	21st to end	Day	34% 10% 16% 23% 16% 1	4339
August	1st to 10th	Day	35% 9% 18% 25% 12% 1	2444
	11th to 20th	Day	37% 10% 18% 24% 10% 1	2357
	21st to end	Day	36% 7% 15% 28% 12% 2	2452
September	1st to 10th	Day	39% 8% 16% 25% 11% 1	2160
	11th to 20th	Day	35% 8% 15% 27% 14% 1	2075
	21st to end	Day	44% 8% 17% 21% 9% 1	1931
October	1st to 10th	Day	49% 7% 14% 17% 11% 1	1800
	11th to 20th	Day	55% 9% 15% 16% 6% 1	1800
	21st to end	Day	65% 6% 11% 12% 5% 1	1980
November	1st to 10th	Day	52% 9% 12% 18% 8% 1	1646
	11th to 20th	Day	54% 8% 17% 14% 6% 1	1520
	21st to end	Day	63% 8% 14% 11% 3	1520
December	1st to 10th	Day	70% 10% 13% 7% 1	1520
	11th to 20th	Day	68% 12% 12% 7% 2	1906
	21st to end	Day	77% 8% 9% 5% 1	2772
January	1st to 10th	Night	65% 11% 14% 8% 2	4429
	11th to 20th	Night	70% 12% 11% 6% 1	4182
	21st to end	Night	74% 9% 10% 5% 2	4532
February	1st to 10th	Night	68% 8% 11% 11% 2	2470
	11th to 20th	Night	64% 9% 13% 11% 4	2405
	21st to end	Night	64% 7% 12% 12% 5%	1968
March	1st to 10th	Night	55% 7% 11% 21% 6%	3418
	11th to 20th	Night	52% 10% 15% 15% 7% 1	3480
	21st to end	Night	42% 7% 11% 26% 13% 1	3817
April	1st to 10th	Night	55% 6% 9% 19% 10% 1	1924
	11th to 20th	Night	48% 7% 10% 20% 13% 2	1859
	21st to end	Night	47% 7% 11% 18% 13% 3	1710
May	1st to 10th	Night	50% 8% 10% 18% 12% 2	2840
	11th to 20th	Night	43% 11% 18% 19% 8% 1	2528
	21st to end	Night	32% 11% 13% 23% 20% 2	2739
June	1st to 10th	Night	43% 8% 11% 20% 16% 1	1520
	11th to 20th	Night	36% 9% 13% 21% 18% 2	1520
	21st to end	Night	40% 7% 15% 20% 16% 1	1520
July	1st to 10th	Night	36% 7% 12% 22% 20% 2	2480
	11th to 20th	Night	33% 7% 15% 30% 13% 1	2472
	21st to end	Night	32% 8% 17% 23% 17% 2	2957
August	1st to 10th	Night	31% 10% 17% 27% 13% 1	1690
	11th to 20th	Night	34% 9% 16% 28% 12%	1643
	21st to end	Night	34% 9% 14% 29% 13% 2	1885
September	1st to 10th	Night	38% 7% 17% 22% 14% 2	1800
	11th to 20th	Night	33% 7% 13% 29% 17% 1	1881
	21st to end	Night	43% 9% 13% 22% 13%	2029
October	1st to 10th	Night	45% 9% 12% 19% 14% 1	2160
	11th to 20th	Night	54% 8% 14% 17% 8% 1	2160
	21st to end	Night	60% 7% 12% 12% 8% 1	2376
November	1st to 10th	Night	47% 8% 12% 21% 11% 2	2428
	11th to 20th	Night	53% 8% 15% 16% 7% 1	2660
	21st to end	Night	60% 10% 15% 13% 2	2660
December	1st to 10th	Night	69% 10% 12% 7% 2	2660
	11th to 20th	Night	67% 9% 12% 9% 2	3288
	21st to end	Night	74% 10% 11% 5% 1	4884

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	24% 17% 34% 16% 6% 2	180
	11th to 20th	Day	26% 26% 31% 13% 3 2	252
	21st to end	Day	23% 20% 34% 17% 5% 1	297
February	1st to 10th	Day	30% 19% 36% 13% 3	270
	11th to 20th	Day	25% 23% 38% 12% 1	270
	21st to end	Day	36% 16% 33% 13% 2	268
March	1st to 10th	Day	24% 15% 34% 19% 7%	460
	11th to 20th	Day	23% 15% 32% 23% 5% 1	460
	21st to end	Day	27% 14% 29% 21% 7% 2	506
April	1st to 10th	Day	21% 14% 33% 23% 7% 1	460
	11th to 20th	Day	28% 13% 27% 19% 10% 4	452
	21st to end	Day	27% 9% 31% 22% 8% 3	460
May	1st to 10th	Day	23% 9% 25% 25% 13% 5%	463
	11th to 20th	Day	17% 6% 25% 28% 19% 6%	487
	21st to end	Day	12% 6% 25% 30% 19% 8%	529
June	1st to 10th	Day	15% 9% 25% 33% 14% 3	490
	11th to 20th	Day	13% 8% 25% 28% 23% 4	490
	21st to end	Day	15% 7% 28% 30% 16% 4	490
July	1st to 10th	Day	9% 4 19% 33% 26% 9%	485
	11th to 20th	Day	14% 6% 19% 29% 21% 10%	484
	21st to end	Day	12% 4 23% 33% 22% 7%	532
August	1st to 10th	Day	14% 2 20% 30% 22% 12%	486
	11th to 20th	Day	10% 7% 16% 30% 25% 11%	456
	21st to end	Day	12% 7% 19% 30% 21% 11%	495
September	1st to 10th	Day	14% 7% 22% 26% 21% 11%	450
	11th to 20th	Day	11% 6% 19% 24% 23% 16%	450
	21st to end	Day	15% 10% 26% 22% 19% 8%	450
October	1st to 10th	Day	23% 12% 21% 18% 16% 9%	450
	11th to 20th	Day	26% 16% 30% 20% 7% 2	450
	21st to end	Day	35% 12% 27% 17% 8%	495
November	1st to 10th	Day	21% 20% 27% 21% 9% 2	302
	11th to 20th	Day	22% 26% 26% 19% 5% 2	180
	21st to end	Day	30% 16% 34% 14% 6%	180
December	1st to 10th	Day	28% 19% 35% 11% 6% 1	180
	11th to 20th	Day	28% 26% 30% 13% 3	180
	21st to end	Day	26% 27% 33% 12% 3	198
January	1st to 10th	Night	29% 20% 32% 14% 6%	760
	11th to 20th	Night	31% 16% 30% 19% 4	760
	21st to end	Night	23% 15% 33% 23% 5%	836
February	1st to 10th	Night	25% 20% 31% 21% 3	760
	11th to 20th	Night	23% 19% 34% 20% 4	743
	21st to end	Night	27% 15% 32% 22% 3	628
March	1st to 10th	Night	22% 12% 35% 24% 6%	760
	11th to 20th	Night	24% 17% 28% 24% 6% 1	760
	21st to end	Night	21% 11% 30% 27% 10% 1	836
April	1st to 10th	Night	25% 13% 30% 27% 5%	760
	11th to 20th	Night	21% 10% 32% 26% 9% 1	735
	21st to end	Night	22% 7% 28% 31% 11% 1	570
May	1st to 10th	Night	20% 7% 23% 33% 15% 3	570
	11th to 20th	Night	16% 5% 25% 41% 12% 1	393
	21st to end	Night	12% 6% 23% 36% 20% 3	411
June	1st to 10th	Night	15% 3 32% 34% 15% 1	380
	11th to 20th	Night	12% 5% 26% 38% 18% 1	380
	21st to end	Night	13% 6% 23% 42% 14% 1	380
July	1st to 10th	Night	9% 4 19% 42% 24% 2	370
	11th to 20th	Night	11% 2 23% 40% 21% 3	368
	21st to end	Night	11% 3 18% 43% 23% 2	604
August	1st to 10th	Night	11% 4 14% 38% 29% 4	567
	11th to 20th	Night	9% 3 17% 34% 31% 5%	549
	21st to end	Night	12% 3 19% 37% 25% 4	697
September	1st to 10th	Night	15% 4 18% 34% 25% 4	720
	11th to 20th	Night	15% 4 17% 30% 26% 8%	720
	21st to end	Night	18% 6% 20% 30% 20% 5%	720
October	1st to 10th	Night	20% 8% 23% 27% 19% 3	720
	11th to 20th	Night	28% 13% 26% 24% 8% 1	720
	21st to end	Night	33% 12% 24% 25% 5%	792
November	1st to 10th	Night	23% 11% 28% 25% 11% 1	740
	11th to 20th	Night	24% 16% 32% 18% 9% 1	760
	21st to end	Night	28% 15% 31% 20% 6%	760
December	1st to 10th	Night	34% 18% 27% 17% 4	760
	11th to 20th	Night	26% 20% 32% 18% 5% 1	760
	21st to end	Night	32% 17% 31% 18% 3	836

Page generated at 2024-08-12 09:52:49. Version ac07

Copyright © 2024 Attilla Danko.