Fenelon Falls
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Fenelon Falls clear sky chart from 2005-11-06 to 2024-03-23.

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% 4 7% 6% 3 5% 5% 5% 7% 32%	78634
	Night	16% 11% 5% 8% 6% 3 5% 4 5% 6% 30%	81175
Transparency	Day	52% 6% 11% 19% 10% 1	78344
	Night	54% 7% 11% 18% 10% 1	80999
Seeing	Day	22% 14% 31% 20% 10% 4	13507
	Night	21% 15% 30% 24% 10% 1	22994

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% 16% 7% 11% 7% 3 4 3 3 3 24%	2517
	11th to 20th	Day	11% 17% 8% 15% 10% 5% 5% 4 4 5% 17%	2620
	21st to end	Day	18% 21% 7% 11% 7% 4 4 4 3 3 18%	3124
February	1st to 10th	Day	15% 15% 6% 13% 10% 3 6% 4 3 4 21%	1710
	11th to 20th	Day	13% 14% 7% 11% 8% 4 6% 3 4 4 26%	1663
	21st to end	Day	17% 14% 6% 9% 7% 3 5% 4 4 5% 24%	1454
March	1st to 10th	Day	15% 11% 5% 8% 9% 3 6% 5% 4 5% 28%	2072
	11th to 20th	Day	12% 14% 5% 8% 6% 5% 5% 4 4 5% 32%	2090
	21st to end	Day	18% 11% 4 6% 5% 3 5% 4 4 5% 35%	2200
April	1st to 10th	Day	20% 11% 4 7% 6% 3 4 4 6% 5% 30%	2160
	11th to 20th	Day	20% 10% 2 5% 5% 3 3 4 5% 6% 37%	2177
	21st to end	Day	20% 10% 3 6% 6% 3 4 4 4 6% 34%	2340
May	1st to 10th	Day	17% 8% 3 6% 6% 4 6% 4 5% 7% 34%	2394
	11th to 20th	Day	15% 9% 3 5% 5% 3 5% 4 5% 7% 40%	2478
	21st to end	Day	13% 6% 2 6% 5% 4 4 5% 5% 8% 41%	2725
June	1st to 10th	Day	18% 7% 3 6% 5% 3 4 5% 5% 8% 37%	2520
	11th to 20th	Day	14% 6% 3 5% 5% 3 4 5% 7% 9% 38%	2520
	21st to end	Day	16% 6% 3 6% 5% 3 5% 4 6% 8% 38%	2520
July	1st to 10th	Day	10% 4 2 4 4 3 6% 5% 6% 9% 45%	2520
	11th to 20th	Day	11% 6% 3 5% 5% 3 6% 5% 7% 9% 40%	2520
	21st to end	Day	10% 5% 3 6% 7% 4 7% 6% 7% 9% 37%	2664
August	1st to 10th	Day	11% 5% 3 5% 6% 4 5% 6% 7% 10% 39%	2327
	11th to 20th	Day	11% 6% 2 5% 6% 4 5% 6% 7% 9% 39%	2303
	21st to end	Day	11% 6% 3 6% 7% 3 5% 5% 7% 9% 39%	2461
September	1st to 10th	Day	13% 6% 3 6% 5% 4 5% 6% 6% 7% 40%	2160
	11th to 20th	Day	13% 5% 2 6% 5% 3 4 4 6% 8% 45%	2103
	21st to end	Day	16% 6% 3 6% 6% 4 5% 5% 5% 6% 38%	1913
October	1st to 10th	Day	19% 9% 4 6% 6% 4 4 4 5% 6% 33%	1800
	11th to 20th	Day	25% 9% 4 8% 6% 3 4 4 5% 6% 25%	1800
	21st to end	Day	27% 13% 4 8% 5% 3 4 4 6% 6% 22%	1980
November	1st to 10th	Day	16% 10% 4 7% 6% 4 5% 4 5% 7% 31%	1561
	11th to 20th	Day	18% 10% 5% 9% 7% 4 4 5% 7% 8% 23%	1520
	21st to end	Day	21% 17% 4 9% 7% 3 5% 5% 5% 6% 19%	1520
December	1st to 10th	Day	17% 20% 8% 13% 7% 4 5% 4 3 5% 15%	1520
	11th to 20th	Day	19% 15% 6% 9% 7% 2 5% 5% 4 5% 24%	1906
	21st to end	Day	26% 18% 6% 11% 6% 3 4 3 3 4 15%	2772
January	1st to 10th	Night	18% 18% 7% 12% 8% 4 4 4 4 4 15%	4429
	11th to 20th	Night	13% 13% 8% 14% 11% 4 6% 5% 5% 5% 17%	4339
	21st to end	Night	18% 16% 8% 10% 7% 4 5% 4 5% 5% 19%	4532
February	1st to 10th	Night	13% 15% 6% 11% 9% 5% 6% 5% 5% 6% 20%	2470
	11th to 20th	Night	13% 14% 6% 10% 7% 4 5% 5% 5% 6% 26%	2403
	21st to end	Night	15% 13% 5% 10% 8% 3 5% 4 5% 6% 26%	1999
March	1st to 10th	Night	14% 11% 5% 8% 7% 4 5% 4 5% 7% 32%	2094
	11th to 20th	Night	13% 14% 6% 8% 6% 3 4 4 4 6% 33%	2089
	21st to end	Night	15% 9% 4 7% 5% 3 4 4 5% 6% 38%	2201
April	1st to 10th	Night	20% 12% 5% 6% 6% 3 5% 4 4 6% 30%	1800
	11th to 20th	Night	17% 8% 4 6% 6% 2 3 4 5% 8% 37%	1747
	21st to end	Night	16% 11% 3 7% 7% 3 3 4 6% 6% 33%	1620
May	1st to 10th	Night	17% 8% 2 5% 5% 3 5% 4 6% 7% 38%	1564
	11th to 20th	Night	13% 7% 3 5% 5% 3 5% 4 5% 7% 45%	1415
	21st to end	Night	11% 5% 3 4 4 3 5% 4 6% 7% 49%	1550
June	1st to 10th	Night	16% 6% 2 5% 6% 3 5% 5% 6% 9% 38%	1440
	11th to 20th	Night	11% 5% 2 5% 6% 3 4 5% 5% 10% 44%	1440
	21st to end	Night	12% 8% 2 6% 6% 3 4 5% 6% 9% 38%	1366
July	1st to 10th	Night	8% 4 2 5% 6% 3 5% 3 5% 7% 52%	1440
	11th to 20th	Night	10% 6% 3 3 4 3 5% 5% 7% 9% 46%	1440
	21st to end	Night	10% 5% 2 4 4 3 6% 5% 6% 8% 48%	1651
August	1st to 10th	Night	9% 5% 2 4 6% 3 4 5% 6% 8% 48%	1611
	11th to 20th	Night	8% 4 3 5% 5% 3 6% 5% 5% 7% 48%	1598
	21st to end	Night	10% 7% 2 4 7% 4 5% 4 6% 7% 44%	1876
September	1st to 10th	Night	11% 6% 2 5% 4 3 5% 5% 6% 8% 43%	1800
	11th to 20th	Night	13% 5% 2 5% 5% 2 3 4 4 7% 50%	1854
	21st to end	Night	16% 7% 3 5% 4 3 5% 4 5% 7% 41%	2046
October	1st to 10th	Night	17% 8% 3 7% 6% 4 4 5% 6% 7% 34%	2160
	11th to 20th	Night	22% 11% 4 8% 6% 3 4 5% 5% 5% 28%	2160
	21st to end	Night	24% 13% 3 7% 6% 3 5% 5% 4 6% 25%	2376
November	1st to 10th	Night	19% 11% 4 6% 5% 3 4 4 5% 6% 33%	2513
	11th to 20th	Night	17% 13% 5% 8% 6% 3 5% 5% 5% 6% 26%	2660
	21st to end	Night	21% 13% 4 9% 7% 4 6% 6% 5% 6% 19%	2660
December	1st to 10th	Night	20% 16% 7% 12% 7% 3 5% 4 4 5% 16%	2660
	11th to 20th	Night	17% 17% 7% 11% 7% 4 4 4 4 5% 20%	3288
	21st to end	Night	27% 19% 7% 12% 7% 3 4 3 3 4 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	62% 7% 12% 11% 8%	2518
	11th to 20th	Day	70% 6% 9% 9% 6%	2620
	21st to end	Day	71% 5% 8% 10% 6% 1	3124
February	1st to 10th	Day	67% 5% 8% 15% 4 1	1710
	11th to 20th	Day	61% 5% 9% 14% 9% 1	1672
	21st to end	Day	62% 5% 9% 15% 8% 1	1454
March	1st to 10th	Day	56% 6% 14% 13% 10% 1	2075
	11th to 20th	Day	54% 6% 9% 18% 11% 2	2090
	21st to end	Day	51% 5% 7% 18% 15% 3	2200
April	1st to 10th	Day	56% 4 9% 19% 11% 2	2160
	11th to 20th	Day	49% 5% 8% 23% 15% 1	2177
	21st to end	Day	52% 4 10% 19% 13% 3	2340
May	1st to 10th	Day	50% 5% 9% 20% 14% 2	2394
	11th to 20th	Day	45% 6% 9% 24% 16% 1	2482
	21st to end	Day	41% 6% 15% 22% 14% 2	2725
June	1st to 10th	Day	46% 7% 11% 21% 15% 1	2520
	11th to 20th	Day	40% 6% 12% 24% 15% 2	2520
	21st to end	Day	42% 8% 14% 22% 12% 1	2520
July	1st to 10th	Day	33% 7% 14% 27% 16% 2	2450
	11th to 20th	Day	38% 8% 15% 29% 9% 1	2445
	21st to end	Day	41% 10% 12% 26% 10% 1	2515
August	1st to 10th	Day	39% 8% 16% 25% 11% 1	2314
	11th to 20th	Day	39% 9% 15% 25% 11% 1	2303
	21st to end	Day	41% 7% 14% 26% 11% 1	2461
September	1st to 10th	Day	41% 7% 14% 27% 10% 1	2160
	11th to 20th	Day	37% 6% 14% 30% 13% 1	2103
	21st to end	Day	46% 7% 13% 26% 9%	1913
October	1st to 10th	Day	52% 5% 11% 19% 11% 1	1800
	11th to 20th	Day	58% 7% 12% 17% 5% 1	1800
	21st to end	Day	62% 5% 11% 15% 6%	1980
November	1st to 10th	Day	50% 8% 15% 18% 8% 1	1561
	11th to 20th	Day	57% 8% 13% 14% 7% 2	1520
	21st to end	Day	64% 7% 11% 13% 5%	1520
December	1st to 10th	Day	72% 6% 9% 10% 3	1520
	11th to 20th	Day	62% 9% 9% 12% 7% 1	1906
	21st to end	Day	73% 4 8% 11% 3	2772
January	1st to 10th	Night	69% 7% 9% 10% 4	4429
	11th to 20th	Night	66% 9% 9% 11% 4 1	4339
	21st to end	Night	66% 6% 11% 10% 6% 1	4532
February	1st to 10th	Night	64% 6% 8% 16% 5% 1	2470
	11th to 20th	Night	57% 6% 11% 18% 8%	2405
	21st to end	Night	57% 6% 10% 19% 8% 1	1999
March	1st to 10th	Night	52% 5% 12% 18% 11% 2	2104
	11th to 20th	Night	53% 5% 11% 19% 11% 2	2090
	21st to end	Night	45% 6% 9% 22% 14% 3	2201
April	1st to 10th	Night	55% 5% 7% 19% 12% 2	1800
	11th to 20th	Night	46% 5% 9% 22% 16% 2	1747
	21st to end	Night	50% 6% 11% 17% 15% 2	1620
May	1st to 10th	Night	45% 5% 12% 19% 15% 3	1564
	11th to 20th	Night	40% 4 9% 26% 18% 3	1416
	21st to end	Night	33% 6% 15% 25% 18% 3	1551
June	1st to 10th	Night	42% 7% 11% 24% 15% 2	1440
	11th to 20th	Night	36% 6% 11% 24% 20% 2	1440
	21st to end	Night	42% 7% 14% 21% 15% 1	1366
July	1st to 10th	Night	31% 7% 10% 29% 21% 3	1400
	11th to 20th	Night	33% 7% 14% 30% 16%	1392
	21st to end	Night	32% 8% 14% 31% 14% 1	1559
August	1st to 10th	Night	33% 7% 20% 26% 14% 1	1600
	11th to 20th	Night	33% 8% 17% 26% 16% 1	1598
	21st to end	Night	38% 8% 12% 29% 12% 1	1876
September	1st to 10th	Night	37% 7% 16% 25% 13% 1	1800
	11th to 20th	Night	33% 6% 13% 33% 14% 1	1854
	21st to end	Night	42% 6% 11% 29% 11%	2046
October	1st to 10th	Night	48% 6% 12% 19% 14% 1	2160
	11th to 20th	Night	56% 7% 11% 20% 6%	2160
	21st to end	Night	60% 7% 10% 13% 10% 1	2376
November	1st to 10th	Night	50% 7% 13% 20% 10%	2513
	11th to 20th	Night	55% 8% 12% 15% 7% 2	2660
	21st to end	Night	62% 8% 14% 12% 4	2660
December	1st to 10th	Night	68% 8% 9% 10% 5%	2660
	11th to 20th	Night	66% 6% 11% 12% 5%	3288
	21st to end	Night	77% 4 7% 9% 3	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	22% 23% 34% 13% 7% 1	180
	11th to 20th	Day	24% 21% 36% 13% 5% 1	209
	21st to end	Day	25% 17% 37% 15% 6%	297
February	1st to 10th	Day	31% 23% 30% 11% 4	270
	11th to 20th	Day	23% 27% 39% 10% 1	270
	21st to end	Day	38% 18% 32% 12%	266
March	1st to 10th	Day	23% 18% 38% 18% 3	460
	11th to 20th	Day	26% 18% 34% 16% 4 1	460
	21st to end	Day	33% 16% 30% 15% 6% 1	470
April	1st to 10th	Day	24% 22% 31% 15% 7% 1	420
	11th to 20th	Day	31% 16% 26% 15% 8% 4	412
	21st to end	Day	29% 14% 34% 14% 8% 2	420
May	1st to 10th	Day	25% 13% 30% 19% 9% 5%	423
	11th to 20th	Day	19% 13% 36% 17% 10% 4	447
	21st to end	Day	16% 11% 34% 21% 11% 7%	485
June	1st to 10th	Day	20% 10% 35% 25% 8% 1	450
	11th to 20th	Day	18% 12% 25% 27% 13% 5%	450
	21st to end	Day	18% 10% 32% 26% 11% 3	450
July	1st to 10th	Day	11% 7% 27% 32% 17% 6%	445
	11th to 20th	Day	15% 8% 27% 28% 16% 7%	444
	21st to end	Day	8% 11% 34% 32% 11% 5%	488
August	1st to 10th	Day	14% 5% 28% 27% 17% 8%	446
	11th to 20th	Day	12% 8% 23% 28% 20% 9%	439
	21st to end	Day	13% 9% 31% 25% 15% 7%	495
September	1st to 10th	Day	13% 11% 30% 25% 16% 6%	450
	11th to 20th	Day	13% 8% 28% 21% 20% 10%	450
	21st to end	Day	17% 13% 29% 23% 13% 5%	450
October	1st to 10th	Day	23% 14% 28% 16% 14% 6%	450
	11th to 20th	Day	26% 19% 32% 16% 4 2	450
	21st to end	Day	32% 19% 29% 14% 5%	495
November	1st to 10th	Day	28% 18% 30% 18% 6%	248
	11th to 20th	Day	28% 21% 34% 12% 3 2	180
	21st to end	Day	31% 16% 44% 8% 2	180
December	1st to 10th	Day	28% 20% 34% 13% 5%	180
	11th to 20th	Day	29% 26% 27% 13% 3 1	180
	21st to end	Day	32% 20% 35% 11% 2	198
January	1st to 10th	Night	25% 22% 29% 16% 6% 1	760
	11th to 20th	Night	27% 18% 31% 18% 5% 1	760
	21st to end	Night	19% 17% 34% 24% 5% 1	836
February	1st to 10th	Night	22% 22% 36% 18% 2	760
	11th to 20th	Night	23% 19% 37% 17% 4	743
	21st to end	Night	24% 21% 33% 18% 3	628
March	1st to 10th	Night	23% 19% 34% 20% 3	760
	11th to 20th	Night	22% 22% 33% 18% 5% 1	760
	21st to end	Night	20% 13% 35% 23% 8%	801
April	1st to 10th	Night	25% 18% 32% 19% 5%	720
	11th to 20th	Night	23% 14% 33% 20% 9% 1	683
	21st to end	Night	20% 13% 33% 24% 9% 1	540
May	1st to 10th	Night	21% 7% 29% 28% 12% 2	484
	11th to 20th	Night	15% 10% 35% 32% 8%	354
	21st to end	Night	12% 8% 33% 33% 14% 1	389
June	1st to 10th	Night	16% 9% 32% 34% 9% 1	360
	11th to 20th	Night	13% 9% 26% 36% 14% 1	360
	21st to end	Night	12% 8% 27% 37% 15% 1	360
July	1st to 10th	Night	7% 7% 23% 41% 21% 1	350
	11th to 20th	Night	10% 7% 28% 33% 20% 1	348
	21st to end	Night	10% 5% 28% 39% 18% 1	471
August	1st to 10th	Night	12% 3 23% 33% 27% 2	537
	11th to 20th	Night	8% 6% 21% 35% 26% 4	534
	21st to end	Night	11% 5% 29% 30% 22% 2	688
September	1st to 10th	Night	12% 7% 30% 28% 19% 4	720
	11th to 20th	Night	13% 6% 26% 30% 21% 4	720
	21st to end	Night	19% 10% 21% 30% 15% 4	720
October	1st to 10th	Night	20% 12% 28% 24% 14% 2	720
	11th to 20th	Night	26% 16% 31% 18% 8% 1	720
	21st to end	Night	30% 18% 28% 19% 4	792
November	1st to 10th	Night	24% 15% 29% 22% 9% 1	740
	11th to 20th	Night	23% 20% 33% 18% 5% 1	760
	21st to end	Night	28% 19% 29% 20% 5%	760
December	1st to 10th	Night	29% 24% 29% 14% 4	760
	11th to 20th	Night	25% 22% 33% 17% 3 1	760
	21st to end	Night	32% 20% 29% 17% 2	836

Page generated at 2024-03-19 23:31:03. Version ac07

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