Gananoque
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Gananoque 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	16% 10% 3 8% 5% 4 4 4 5% 7% 33%	95735
	Night	18% 11% 4 8% 5% 4 4 3 5% 6% 31%	92987
Transparency	Day	50% 8% 13% 20% 9% 1	95454
	Night	54% 7% 12% 18% 9% 1	92822
Seeing	Day	23% 15% 30% 21% 10% 2	14231
	Night	24% 13% 29% 24% 9% 1	23353

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	17% 17% 5% 10% 6% 4 5% 3 4 5% 24%	2517
	11th to 20th	Day	14% 17% 8% 14% 6% 5% 4 3 4 5% 19%	2520
	21st to end	Day	17% 20% 7% 13% 7% 6% 4 3 3 4 16%	2994
February	1st to 10th	Day	16% 17% 5% 11% 7% 6% 5% 4 4 5% 20%	1710
	11th to 20th	Day	15% 14% 6% 11% 5% 5% 5% 4 5% 4 26%	1668
	21st to end	Day	20% 15% 5% 9% 7% 5% 5% 3 4 5% 23%	1570
March	1st to 10th	Day	22% 12% 4 9% 5% 4 4 3 3 5% 29%	3168
	11th to 20th	Day	12% 16% 5% 10% 5% 5% 4 3 4 5% 30%	3480
	21st to end	Day	15% 9% 3 8% 5% 3 4 3 4 6% 39%	3996
April	1st to 10th	Day	20% 12% 4 7% 5% 4 4 3 3 6% 32%	2280
	11th to 20th	Day	22% 8% 3 6% 4 4 4 3 4 6% 37%	2254
	21st to end	Day	21% 10% 4 7% 4 4 5% 3 4 5% 32%	2356
May	1st to 10th	Day	21% 9% 3 7% 5% 4 4 3 5% 7% 31%	4426
	11th to 20th	Day	16% 8% 3 8% 5% 5% 4 4 6% 7% 34%	4398
	21st to end	Day	13% 6% 2 6% 5% 4 5% 4 6% 9% 40%	4837
June	1st to 10th	Day	19% 9% 2 6% 5% 5% 5% 3 5% 8% 33%	2660
	11th to 20th	Day	15% 6% 2 5% 5% 5% 5% 5% 6% 8% 38%	2660
	21st to end	Day	16% 7% 3 7% 5% 5% 5% 4 6% 8% 35%	2660
July	1st to 10th	Day	11% 6% 2 6% 5% 5% 5% 5% 7% 10% 40%	4440
	11th to 20th	Day	12% 6% 2 5% 4 4 5% 4 7% 9% 42%	4440
	21st to end	Day	10% 5% 2 6% 4 4 6% 5% 8% 10% 40%	4814
August	1st to 10th	Day	12% 7% 2 7% 4 4 5% 4 6% 8% 41%	2543
	11th to 20th	Day	11% 6% 2 6% 4 4 6% 5% 8% 9% 39%	2326
	21st to end	Day	13% 5% 2 7% 4 4 5% 4 6% 8% 41%	2376
September	1st to 10th	Day	13% 6% 2 6% 4 4 4 4 6% 8% 43%	2160
	11th to 20th	Day	11% 6% 2 6% 4 4 4 3 5% 7% 47%	2160
	21st to end	Day	17% 7% 3 6% 4 5% 4 4 6% 6% 39%	1917
October	1st to 10th	Day	21% 8% 3 7% 5% 3 5% 3 5% 6% 36%	1800
	11th to 20th	Day	20% 10% 3 8% 5% 5% 5% 3 5% 7% 30%	1800
	21st to end	Day	26% 11% 3 7% 6% 5% 4 3 4 5% 27%	1872
November	1st to 10th	Day	16% 9% 3 7% 5% 5% 4 4 6% 7% 32%	1671
	11th to 20th	Day	16% 13% 4 9% 5% 5% 5% 3 5% 6% 31%	1544
	21st to end	Day	22% 14% 4 9% 6% 5% 4 4 6% 6% 22%	1520
December	1st to 10th	Day	24% 15% 5% 10% 5% 4 4 3 5% 6% 18%	1520
	11th to 20th	Day	21% 17% 5% 10% 6% 4 3 3 5% 5% 21%	1906
	21st to end	Day	28% 17% 5% 10% 5% 4 4 2 3 4 19%	2772
January	1st to 10th	Night	20% 16% 5% 11% 5% 4 4 4 4 5% 22%	4429
	11th to 20th	Night	15% 15% 7% 15% 7% 6% 5% 3 4 5% 18%	4440
	21st to end	Night	22% 17% 6% 10% 5% 5% 4 3 4 4 20%	4660
February	1st to 10th	Night	18% 15% 5% 13% 6% 6% 4 4 4 5% 21%	2470
	11th to 20th	Night	14% 14% 5% 10% 7% 5% 5% 3 4 6% 29%	2396
	21st to end	Night	19% 14% 4 10% 5% 4 4 4 5% 4 27%	1884
March	1st to 10th	Night	20% 12% 4 8% 5% 5% 4 3 4 5% 32%	3670
	11th to 20th	Night	21% 17% 4 8% 4 4 3 3 4 6% 27%	3479
	21st to end	Night	17% 10% 3 9% 4 3 3 3 4 5% 39%	3635
April	1st to 10th	Night	21% 10% 3 7% 4 4 3 4 4 5% 34%	1900
	11th to 20th	Night	21% 8% 3 6% 4 5% 4 3 5% 6% 36%	1875
	21st to end	Night	22% 9% 3 7% 4 4 4 3 4 6% 33%	1840
May	1st to 10th	Night	23% 9% 3 7% 5% 4 4 3 5% 7% 29%	2514
	11th to 20th	Night	19% 9% 3 7% 5% 4 4 3 5% 6% 34%	2495
	21st to end	Night	14% 6% 3 5% 4 4 4 4 6% 9% 41%	2738
June	1st to 10th	Night	15% 7% 3 7% 6% 5% 5% 3 6% 9% 33%	1520
	11th to 20th	Night	13% 5% 2 6% 5% 4 5% 4 6% 8% 42%	1520
	21st to end	Night	19% 7% 3 6% 4 4 4 5% 5% 8% 35%	1520
July	1st to 10th	Night	12% 7% 3 7% 5% 5% 5% 4 6% 8% 38%	2520
	11th to 20th	Night	14% 6% 2 5% 3 4 4 4 7% 8% 44%	2520
	21st to end	Night	10% 7% 2 6% 5% 4 4 4 7% 7% 44%	2739
August	1st to 10th	Night	9% 6% 2 6% 5% 5% 6% 4 6% 9% 43%	1612
	11th to 20th	Night	11% 7% 3 6% 5% 3 5% 3 6% 9% 42%	1656
	21st to end	Night	11% 5% 2 6% 5% 4 3 5% 6% 8% 43%	1980
September	1st to 10th	Night	12% 6% 2 7% 4 4 4 4 6% 7% 46%	1800
	11th to 20th	Night	14% 6% 1 5% 3 3 3 3 6% 7% 48%	1800
	21st to end	Night	16% 6% 2 6% 4 5% 3 3 6% 7% 42%	2041
October	1st to 10th	Night	19% 8% 3 7% 4 3 4 4 5% 7% 35%	2160
	11th to 20th	Night	20% 8% 3 7% 6% 5% 5% 3 5% 6% 32%	2160
	21st to end	Night	25% 10% 3 8% 5% 5% 3 3 5% 5% 28%	2484
November	1st to 10th	Night	18% 10% 3 7% 4 3 4 3 5% 6% 37%	2407
	11th to 20th	Night	18% 11% 3 7% 4 4 5% 4 5% 8% 32%	2631
	21st to end	Night	22% 13% 3 9% 5% 4 5% 4 5% 6% 24%	2660
December	1st to 10th	Night	22% 15% 5% 10% 6% 5% 4 3 5% 5% 20%	2660
	11th to 20th	Night	22% 15% 4 9% 5% 4 3 3 5% 4 27%	3288
	21st to end	Night	31% 14% 4 11% 4 4 3 3 4 5% 16%	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	64% 9% 11% 11% 4 1	2518
	11th to 20th	Day	70% 10% 8% 6% 5%	2520
	21st to end	Day	72% 7% 9% 8% 3 1	2994
February	1st to 10th	Day	65% 7% 10% 14% 4 1	1710
	11th to 20th	Day	60% 6% 10% 15% 7% 1	1677
	21st to end	Day	63% 7% 9% 12% 8% 1	1570
March	1st to 10th	Day	58% 6% 11% 17% 8% 1	3171
	11th to 20th	Day	53% 8% 16% 13% 9% 1	3480
	21st to end	Day	43% 8% 11% 23% 13% 3	3996
April	1st to 10th	Day	53% 5% 9% 18% 12% 2	2280
	11th to 20th	Day	48% 6% 9% 22% 14% 2	2254
	21st to end	Day	52% 6% 10% 16% 12% 4	2356
May	1st to 10th	Day	50% 9% 11% 20% 9% 1	4440
	11th to 20th	Day	46% 11% 13% 21% 9% 1	4402
	21st to end	Day	38% 9% 14% 24% 12% 1	4837
June	1st to 10th	Day	48% 8% 13% 19% 12% 1	2660
	11th to 20th	Day	42% 8% 12% 25% 11% 2	2660
	21st to end	Day	44% 9% 14% 20% 12% 1	2660
July	1st to 10th	Day	37% 6% 13% 30% 13% 1	4370
	11th to 20th	Day	36% 7% 16% 32% 9%	4365
	21st to end	Day	37% 9% 16% 28% 10%	4661
August	1st to 10th	Day	39% 9% 16% 25% 11%	2529
	11th to 20th	Day	37% 10% 18% 25% 10%	2326
	21st to end	Day	38% 8% 15% 28% 10% 1	2376
September	1st to 10th	Day	38% 8% 16% 26% 12% 1	2160
	11th to 20th	Day	37% 6% 12% 28% 15% 1	2160
	21st to end	Day	45% 8% 13% 25% 10%	1917
October	1st to 10th	Day	51% 6% 11% 21% 11% 1	1800
	11th to 20th	Day	56% 7% 15% 18% 4 1	1800
	21st to end	Day	60% 7% 11% 14% 7%	1872
November	1st to 10th	Day	50% 8% 17% 19% 7% 1	1671
	11th to 20th	Day	56% 8% 12% 16% 7% 2	1544
	21st to end	Day	64% 9% 13% 8% 6%	1520
December	1st to 10th	Day	69% 8% 12% 9% 1	1520
	11th to 20th	Day	67% 8% 11% 11% 2	1906
	21st to end	Day	71% 7% 7% 12% 2	2772
January	1st to 10th	Night	66% 9% 12% 10% 3	4429
	11th to 20th	Night	69% 11% 9% 8% 3	4440
	21st to end	Night	69% 8% 9% 9% 5% 1	4660
February	1st to 10th	Night	67% 6% 11% 11% 5%	2470
	11th to 20th	Night	59% 7% 11% 17% 7%	2398
	21st to end	Night	58% 7% 11% 16% 7% 1	1884
March	1st to 10th	Night	53% 6% 10% 21% 8%	3680
	11th to 20th	Night	59% 7% 13% 13% 8%	3480
	21st to end	Night	47% 6% 8% 21% 15% 2	3635
April	1st to 10th	Night	52% 5% 9% 21% 11% 2	1900
	11th to 20th	Night	50% 6% 10% 17% 15% 1	1875
	21st to end	Night	52% 6% 9% 17% 14% 3	1840
May	1st to 10th	Night	53% 8% 10% 16% 9% 3	2520
	11th to 20th	Night	49% 10% 13% 18% 9% 2	2496
	21st to end	Night	38% 8% 13% 20% 19% 2	2739
June	1st to 10th	Night	45% 9% 13% 21% 10% 1	1520
	11th to 20th	Night	39% 8% 12% 22% 17% 2	1520
	21st to end	Night	45% 8% 12% 22% 13% 1	1520
July	1st to 10th	Night	42% 6% 12% 23% 16% 1	2480
	11th to 20th	Night	38% 5% 14% 34% 9%	2472
	21st to end	Night	37% 8% 14% 27% 13% 1	2651
August	1st to 10th	Night	37% 8% 18% 25% 11% 1	1602
	11th to 20th	Night	39% 8% 14% 26% 13% 1	1656
	21st to end	Night	36% 8% 15% 30% 11%	1980
September	1st to 10th	Night	37% 8% 15% 26% 12% 1	1800
	11th to 20th	Night	34% 7% 14% 29% 15% 1	1800
	21st to end	Night	41% 8% 12% 27% 12% 1	2041
October	1st to 10th	Night	51% 6% 11% 20% 10% 1	2160
	11th to 20th	Night	52% 7% 15% 18% 7% 1	2160
	21st to end	Night	61% 7% 13% 12% 7% 1	2484
November	1st to 10th	Night	50% 6% 15% 19% 9% 1	2407
	11th to 20th	Night	52% 8% 13% 17% 8% 2	2631
	21st to end	Night	62% 8% 12% 13% 4	2660
December	1st to 10th	Night	69% 7% 11% 11% 2	2660
	11th to 20th	Night	63% 6% 11% 14% 5% 1	3288
	21st to end	Night	71% 7% 10% 10% 2	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	28% 17% 32% 15% 7% 1	180
	11th to 20th	Day	31% 20% 31% 15% 3 1	180
	21st to end	Day	24% 20% 32% 20% 5%	261
February	1st to 10th	Day	31% 26% 30% 13% 1	270
	11th to 20th	Day	28% 26% 35% 10% 1	275
	21st to end	Day	34% 18% 30% 17% 2	382
March	1st to 10th	Day	27% 15% 32% 19% 7%	460
	11th to 20th	Day	27% 19% 30% 19% 5%	460
	21st to end	Day	31% 16% 30% 15% 6% 1	506
April	1st to 10th	Day	29% 19% 30% 15% 7%	460
	11th to 20th	Day	27% 23% 24% 17% 6% 4	452
	21st to end	Day	29% 14% 32% 15% 8% 2	460
May	1st to 10th	Day	23% 15% 32% 18% 10% 2	463
	11th to 20th	Day	16% 14% 33% 24% 10% 3	487
	21st to end	Day	18% 12% 31% 23% 13% 2	529
June	1st to 10th	Day	22% 12% 34% 21% 9% 2	490
	11th to 20th	Day	19% 13% 30% 23% 12% 3	490
	21st to end	Day	20% 14% 31% 23% 10% 2	490
July	1st to 10th	Day	13% 10% 27% 30% 16% 3	485
	11th to 20th	Day	15% 9% 29% 29% 14% 4	484
	21st to end	Day	12% 11% 33% 32% 11% 1	532
August	1st to 10th	Day	13% 9% 30% 27% 17% 3	486
	11th to 20th	Day	14% 8% 23% 30% 18% 8%	456
	21st to end	Day	15% 9% 33% 23% 15% 6%	495
September	1st to 10th	Day	16% 8% 30% 28% 12% 6%	450
	11th to 20th	Day	12% 8% 28% 25% 18% 10%	450
	21st to end	Day	20% 10% 25% 26% 16% 3	450
October	1st to 10th	Day	28% 14% 22% 18% 13% 5%	450
	11th to 20th	Day	24% 21% 29% 16% 7% 2	450
	21st to end	Day	35% 14% 27% 19% 5%	441
November	1st to 10th	Day	25% 20% 29% 18% 7% 1	365
	11th to 20th	Day	27% 20% 34% 11% 7% 1	204
	21st to end	Day	27% 23% 35% 11% 4 1	180
December	1st to 10th	Day	38% 14% 27% 17% 3	180
	11th to 20th	Day	32% 23% 32% 10% 3	180
	21st to end	Day	32% 21% 27% 17% 3	198
January	1st to 10th	Night	32% 18% 27% 18% 5%	760
	11th to 20th	Night	30% 18% 29% 19% 4 1	760
	21st to end	Night	24% 14% 31% 24% 6%	836
February	1st to 10th	Night	25% 22% 32% 18% 3	760
	11th to 20th	Night	23% 17% 37% 20% 3	743
	21st to end	Night	28% 15% 33% 21% 3	628
March	1st to 10th	Night	26% 14% 32% 24% 4	760
	11th to 20th	Night	27% 17% 28% 23% 5% 1	760
	21st to end	Night	24% 13% 33% 22% 7%	836
April	1st to 10th	Night	26% 13% 32% 24% 4	760
	11th to 20th	Night	25% 16% 31% 21% 7%	751
	21st to end	Night	27% 11% 28% 23% 9% 1	700
May	1st to 10th	Night	26% 9% 26% 27% 9% 2	380
	11th to 20th	Night	16% 9% 32% 35% 7% 1	374
	21st to end	Night	14% 10% 31% 30% 14% 1	411
June	1st to 10th	Night	20% 7% 27% 35% 10% 1	380
	11th to 20th	Night	14% 9% 27% 34% 14% 1	380
	21st to end	Night	18% 8% 27% 34% 13%	380
July	1st to 10th	Night	12% 4 31% 36% 17% 1	370
	11th to 20th	Night	12% 5% 23% 37% 22% 2	368
	21st to end	Night	14% 5% 26% 41% 13% 1	416
August	1st to 10th	Night	15% 3 24% 35% 22% 1	478
	11th to 20th	Night	15% 5% 20% 31% 24% 4	562
	21st to end	Night	13% 6% 28% 33% 18% 2	792
September	1st to 10th	Night	17% 6% 25% 31% 18% 3	720
	11th to 20th	Night	16% 7% 21% 29% 23% 5%	720
	21st to end	Night	17% 10% 26% 25% 19% 2	720
October	1st to 10th	Night	26% 13% 26% 17% 16% 2	720
	11th to 20th	Night	26% 14% 27% 24% 9% 1	720
	21st to end	Night	34% 11% 29% 21% 5%	792
November	1st to 10th	Night	27% 14% 29% 21% 9%	740
	11th to 20th	Night	27% 18% 30% 17% 8% 1	760
	21st to end	Night	33% 18% 27% 16% 6%	760
December	1st to 10th	Night	34% 19% 26% 18% 4	760
	11th to 20th	Night	30% 19% 31% 17% 2 1	760
	21st to end	Night	35% 16% 30% 16% 2	836

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

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