Smiths Falls
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Smiths Falls clear sky chart from 2005-11-06 to 2024-11-02.

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	17% 10% 3 8% 5% 5% 5% 4 5% 7% 33%	101549
	Night	18% 11% 4 8% 5% 4 4 3 5% 6% 32%	97423
Transparency	Day	50% 6% 12% 21% 10% 1	101307
	Night	53% 5% 12% 19% 9% 1	97285
Seeing	Day	24% 16% 30% 20% 8% 3	14500
	Night	23% 13% 30% 24% 9% 1	23590

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	15% 18% 5% 11% 6% 5% 5% 3 4 5% 24%	2517
	11th to 20th	Day	14% 15% 6% 14% 7% 6% 4 4 5% 5% 22%	2520
	21st to end	Day	17% 18% 6% 13% 6% 6% 5% 3 4 4 17%	2936
February	1st to 10th	Day	17% 15% 5% 11% 7% 5% 5% 4 4 5% 23%	1710
	11th to 20th	Day	13% 16% 5% 10% 6% 5% 4 3 4 6% 27%	1666
	21st to end	Day	19% 15% 4 9% 7% 5% 5% 4 4 5% 23%	1570
March	1st to 10th	Day	20% 14% 4 10% 5% 4 4 3 4 5% 27%	3143
	11th to 20th	Day	13% 15% 5% 9% 6% 6% 5% 3 5% 5% 29%	3480
	21st to end	Day	14% 9% 3 7% 5% 3 3 3 5% 6% 41%	4006
April	1st to 10th	Day	21% 12% 4 7% 5% 4 4 3 5% 6% 31%	2280
	11th to 20th	Day	21% 9% 3 7% 4 4 4 3 4 5% 35%	2254
	21st to end	Day	24% 9% 3 8% 5% 4 4 2 5% 6% 31%	2389
May	1st to 10th	Day	20% 9% 3 7% 5% 5% 4 4 5% 6% 32%	4426
	11th to 20th	Day	17% 10% 3 8% 5% 4 4 4 5% 7% 33%	4398
	21st to end	Day	15% 6% 2 7% 4 4 5% 5% 5% 9% 39%	4837
June	1st to 10th	Day	21% 8% 3 7% 5% 4 5% 4 5% 7% 30%	2660
	11th to 20th	Day	15% 6% 2 6% 5% 4 5% 5% 6% 8% 37%	2660
	21st to end	Day	19% 8% 3 7% 6% 5% 5% 4 6% 7% 32%	2660
July	1st to 10th	Day	12% 6% 2 7% 5% 5% 5% 5% 7% 10% 36%	4440
	11th to 20th	Day	13% 6% 2 6% 4 5% 5% 4 7% 9% 40%	4440
	21st to end	Day	11% 5% 2 6% 4 5% 6% 4 6% 9% 42%	4814
August	1st to 10th	Day	17% 8% 3 7% 4 5% 5% 3 5% 7% 36%	4301
	11th to 20th	Day	17% 6% 2 6% 4 4 5% 4 6% 8% 38%	3990
	21st to end	Day	15% 5% 2 6% 4 4 5% 4 6% 9% 39%	4180
September	1st to 10th	Day	14% 5% 2 5% 5% 5% 6% 4 6% 8% 41%	2280
	11th to 20th	Day	12% 6% 2 6% 4 3 4 4 6% 8% 46%	2280
	21st to end	Day	18% 6% 2 6% 4 4 4 4 5% 6% 40%	2024
October	1st to 10th	Day	21% 8% 3 7% 5% 4 3 3 4 6% 37%	1900
	11th to 20th	Day	21% 10% 3 8% 5% 4 5% 4 5% 6% 30%	1900
	21st to end	Day	25% 11% 3 7% 4 5% 5% 3 4 5% 27%	1957
November	1st to 10th	Day	16% 8% 4 6% 5% 6% 6% 4 5% 6% 33%	1680
	11th to 20th	Day	18% 14% 3 9% 6% 4 4 3 5% 6% 29%	1533
	21st to end	Day	21% 14% 5% 9% 7% 5% 5% 3 5% 5% 21%	1520
December	1st to 10th	Day	24% 16% 6% 10% 6% 4 4 3 5% 5% 17%	1520
	11th to 20th	Day	22% 15% 4 9% 5% 4 5% 3 4 4 25%	1906
	21st to end	Day	27% 18% 5% 11% 5% 3 3 2 3 3 20%	2772
January	1st to 10th	Night	18% 15% 7% 12% 5% 5% 4 3 5% 5% 21%	4429
	11th to 20th	Night	14% 15% 6% 14% 8% 6% 5% 3 5% 5% 20%	4440
	21st to end	Night	19% 18% 6% 11% 6% 6% 4 3 3 4 20%	4715
February	1st to 10th	Night	15% 16% 5% 11% 6% 6% 3 4 5% 5% 22%	2470
	11th to 20th	Night	14% 15% 5% 11% 6% 5% 4 4 5% 5% 29%	2399
	21st to end	Night	16% 15% 4 8% 6% 5% 4 3 4 4 30%	1884
March	1st to 10th	Night	21% 12% 4 8% 5% 4 4 3 3 4 32%	3696
	11th to 20th	Night	19% 16% 4 9% 5% 4 4 3 5% 6% 26%	3479
	21st to end	Night	15% 10% 3 8% 4 4 4 3 4 6% 39%	3626
April	1st to 10th	Night	21% 10% 4 7% 5% 4 3 3 4 6% 33%	1900
	11th to 20th	Night	22% 8% 2 8% 5% 4 3 3 4 5% 37%	1875
	21st to end	Night	21% 11% 3 7% 4 3 5% 4 4 6% 33%	1808
May	1st to 10th	Night	22% 9% 3 7% 5% 4 5% 4 6% 6% 30%	2514
	11th to 20th	Night	20% 9% 3 6% 4 4 4 3 5% 6% 37%	2495
	21st to end	Night	14% 7% 2 5% 4 4 4 3 6% 8% 41%	2738
June	1st to 10th	Night	17% 7% 2 6% 6% 5% 5% 4 6% 7% 34%	1520
	11th to 20th	Night	15% 7% 2 5% 5% 4 5% 3 7% 8% 41%	1520
	21st to end	Night	17% 8% 2 7% 5% 5% 5% 4 6% 8% 34%	1520
July	1st to 10th	Night	11% 7% 3 8% 7% 5% 5% 4 6% 9% 36%	2520
	11th to 20th	Night	14% 5% 2 6% 4 4 5% 4 6% 8% 43%	2520
	21st to end	Night	11% 5% 2 6% 4 5% 5% 4 6% 7% 43%	2739
August	1st to 10th	Night	11% 7% 3 7% 4 4 5% 4 6% 7% 42%	2624
	11th to 20th	Night	12% 7% 2 7% 4 4 4 4 6% 8% 41%	2806
	21st to end	Night	11% 5% 3 6% 5% 5% 5% 5% 6% 8% 43%	3476
September	1st to 10th	Night	12% 6% 3 7% 5% 4 3 3 4 6% 47%	1900
	11th to 20th	Night	14% 4 2 4 3 3 3 4 6% 7% 51%	1900
	21st to end	Night	17% 6% 2 6% 4 4 3 4 4 8% 42%	2151
October	1st to 10th	Night	17% 8% 3 6% 5% 4 5% 3 5% 6% 38%	2280
	11th to 20th	Night	21% 9% 2 7% 4 4 4 4 5% 6% 33%	2280
	21st to end	Night	23% 11% 3 7% 5% 4 4 4 5% 6% 29%	2641
November	1st to 10th	Night	19% 10% 4 6% 4 3 4 3 4 6% 36%	2421
	11th to 20th	Night	18% 11% 4 8% 5% 4 5% 3 5% 6% 31%	2645
	21st to end	Night	21% 13% 5% 8% 5% 4 4 3 4 7% 25%	2660
December	1st to 10th	Night	20% 18% 6% 11% 6% 5% 4 3 5% 4 18%	2660
	11th to 20th	Night	22% 15% 4 9% 5% 5% 3 3 4 4 27%	3288
	21st to end	Night	30% 16% 4 12% 5% 4 3 3 3 4 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	62% 6% 14% 11% 5% 1	2518
	11th to 20th	Day	64% 5% 11% 12% 7% 1	2520
	21st to end	Day	70% 6% 10% 9% 4 1	2936
February	1st to 10th	Day	63% 5% 9% 18% 4 1	1710
	11th to 20th	Day	58% 5% 11% 17% 9% 1	1675
	21st to end	Day	63% 5% 10% 12% 9% 1	1570
March	1st to 10th	Day	59% 5% 9% 18% 9% 1	3146
	11th to 20th	Day	54% 6% 13% 15% 10% 1	3480
	21st to end	Day	43% 5% 8% 23% 17% 4	4006
April	1st to 10th	Day	54% 4 7% 19% 13% 3	2280
	11th to 20th	Day	51% 5% 7% 19% 16% 2	2254
	21st to end	Day	55% 5% 8% 15% 14% 4	2389
May	1st to 10th	Day	51% 6% 10% 21% 10% 2	4440
	11th to 20th	Day	49% 7% 13% 21% 9% 1	4402
	21st to end	Day	41% 7% 13% 24% 14% 1	4837
June	1st to 10th	Day	52% 6% 10% 19% 12% 1	2660
	11th to 20th	Day	43% 6% 11% 25% 12% 2	2660
	21st to end	Day	50% 7% 12% 19% 11% 1	2660
July	1st to 10th	Day	41% 6% 13% 28% 12% 1	4370
	11th to 20th	Day	38% 6% 15% 31% 9%	4365
	21st to end	Day	38% 7% 13% 31% 11%	4661
August	1st to 10th	Day	48% 5% 14% 23% 10%	4287
	11th to 20th	Day	42% 6% 15% 28% 9%	4029
	21st to end	Day	41% 5% 16% 27% 11%	4180
September	1st to 10th	Day	40% 7% 14% 27% 12%	2280
	11th to 20th	Day	37% 5% 13% 31% 14%	2280
	21st to end	Day	44% 6% 14% 26% 10%	2024
October	1st to 10th	Day	50% 4 11% 24% 10% 1	1900
	11th to 20th	Day	54% 6% 14% 18% 7% 1	1900
	21st to end	Day	58% 6% 12% 16% 8% 1	1957
November	1st to 10th	Day	50% 6% 14% 21% 8% 1	1680
	11th to 20th	Day	57% 5% 11% 16% 10% 1	1533
	21st to end	Day	64% 6% 12% 11% 6%	1520
December	1st to 10th	Day	68% 6% 11% 11% 3	1520
	11th to 20th	Day	64% 5% 14% 14% 3	1906
	21st to end	Day	72% 4 7% 13% 3	2772
January	1st to 10th	Night	64% 5% 16% 11% 3	4429
	11th to 20th	Night	66% 6% 13% 10% 4	4440
	21st to end	Night	70% 4 10% 10% 5% 1	4715
February	1st to 10th	Night	64% 4 11% 15% 6% 1	2470
	11th to 20th	Night	57% 5% 11% 20% 7%	2401
	21st to end	Night	59% 4 9% 17% 10% 1	1884
March	1st to 10th	Night	56% 4 9% 21% 8% 1	3706
	11th to 20th	Night	58% 5% 15% 13% 8% 1	3480
	21st to end	Night	46% 4 7% 23% 16% 3	3626
April	1st to 10th	Night	52% 4 9% 20% 13% 2	1900
	11th to 20th	Night	51% 4 8% 19% 16% 2	1875
	21st to end	Night	52% 6% 9% 16% 15% 3	1808
May	1st to 10th	Night	53% 6% 11% 18% 9% 3	2520
	11th to 20th	Night	47% 6% 13% 21% 11% 1	2496
	21st to end	Night	39% 7% 14% 21% 17% 2	2739
June	1st to 10th	Night	47% 8% 13% 20% 11% 1	1520
	11th to 20th	Night	41% 6% 12% 22% 17% 2	1520
	21st to end	Night	47% 8% 12% 20% 13%	1520
July	1st to 10th	Night	44% 6% 13% 22% 14% 1	2480
	11th to 20th	Night	39% 5% 13% 34% 8%	2472
	21st to end	Night	38% 7% 15% 24% 14% 1	2651
August	1st to 10th	Night	40% 7% 14% 26% 12% 1	2614
	11th to 20th	Night	41% 5% 16% 30% 7%	2833
	21st to end	Night	37% 7% 15% 28% 11% 1	3476
September	1st to 10th	Night	38% 6% 12% 29% 14% 1	1900
	11th to 20th	Night	33% 5% 15% 34% 12% 1	1900
	21st to end	Night	41% 6% 12% 30% 11% 1	2151
October	1st to 10th	Night	46% 6% 11% 23% 13% 1	2280
	11th to 20th	Night	50% 6% 14% 21% 9%	2280
	21st to end	Night	55% 6% 14% 15% 9%	2641
November	1st to 10th	Night	49% 5% 15% 21% 9% 1	2421
	11th to 20th	Night	53% 6% 13% 17% 10% 1	2645
	21st to end	Night	61% 5% 13% 16% 5%	2660
December	1st to 10th	Night	68% 6% 10% 13% 3	2660
	11th to 20th	Night	62% 4 10% 16% 7% 1	3288
	21st to end	Night	73% 5% 8% 12% 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	26% 21% 34% 14% 4	180
	11th to 20th	Day	32% 18% 30% 17% 2 1	180
	21st to end	Day	27% 18% 36% 16% 4	245
February	1st to 10th	Day	31% 27% 29% 11% 1	270
	11th to 20th	Day	27% 28% 36% 7% 1	273
	21st to end	Day	34% 18% 34% 13% 2	382
March	1st to 10th	Day	27% 21% 31% 17% 4	460
	11th to 20th	Day	29% 20% 33% 15% 3	460
	21st to end	Day	32% 21% 27% 13% 6% 1	506
April	1st to 10th	Day	31% 23% 27% 14% 5% 1	460
	11th to 20th	Day	33% 20% 23% 14% 7% 3	452
	21st to end	Day	33% 17% 29% 14% 6% 2	460
May	1st to 10th	Day	25% 17% 31% 19% 7% 2	463
	11th to 20th	Day	22% 15% 33% 20% 7% 2	487
	21st to end	Day	21% 15% 32% 21% 10% 2	529
June	1st to 10th	Day	26% 12% 30% 22% 9% 1	490
	11th to 20th	Day	15% 16% 33% 23% 10% 2	490
	21st to end	Day	22% 12% 32% 20% 11% 3	490
July	1st to 10th	Day	13% 8% 29% 33% 14% 3	485
	11th to 20th	Day	13% 11% 32% 27% 14% 3	484
	21st to end	Day	14% 8% 32% 32% 11% 3	532
August	1st to 10th	Day	16% 10% 27% 30% 13% 3	486
	11th to 20th	Day	16% 6% 27% 29% 16% 6%	479
	21st to end	Day	16% 11% 30% 24% 11% 7%	539
September	1st to 10th	Day	16% 13% 29% 24% 12% 7%	490
	11th to 20th	Day	13% 8% 25% 24% 18% 12%	490
	21st to end	Day	20% 11% 27% 24% 13% 4	490
October	1st to 10th	Day	24% 15% 26% 19% 12% 4	490
	11th to 20th	Day	28% 19% 29% 17% 6% 1	490
	21st to end	Day	32% 16% 29% 19% 4	469
November	1st to 10th	Day	27% 20% 29% 18% 7% 1	368
	11th to 20th	Day	28% 21% 32% 10% 7% 2	193
	21st to end	Day	28% 24% 31% 14% 3	180
December	1st to 10th	Day	35% 17% 33% 13% 2	180
	11th to 20th	Day	33% 27% 29% 9% 2 1	180
	21st to end	Day	37% 19% 29% 12% 2 1	198
January	1st to 10th	Night	29% 19% 31% 18% 4	760
	11th to 20th	Night	31% 17% 28% 20% 4 1	760
	21st to end	Night	22% 15% 34% 24% 5%	836
February	1st to 10th	Night	25% 22% 32% 19% 2	760
	11th to 20th	Night	23% 19% 39% 17% 3	743
	21st to end	Night	26% 21% 32% 18% 4	628
March	1st to 10th	Night	26% 14% 34% 22% 4	760
	11th to 20th	Night	26% 21% 28% 19% 4 1	760
	21st to end	Night	24% 15% 31% 23% 6% 1	836
April	1st to 10th	Night	27% 16% 30% 23% 4	760
	11th to 20th	Night	27% 19% 28% 19% 7% 1	751
	21st to end	Night	26% 13% 30% 23% 7% 1	668
May	1st to 10th	Night	26% 8% 27% 28% 10% 2	380
	11th to 20th	Night	17% 12% 34% 29% 8%	374
	21st to end	Night	14% 9% 39% 27% 12%	411
June	1st to 10th	Night	17% 9% 29% 34% 9%	380
	11th to 20th	Night	18% 9% 29% 31% 13% 1	380
	21st to end	Night	20% 7% 31% 29% 13%	380
July	1st to 10th	Night	9% 7% 31% 39% 14% 1	370
	11th to 20th	Night	13% 5% 26% 40% 15% 1	368
	21st to end	Night	11% 4 29% 42% 13% 1	416
August	1st to 10th	Night	12% 5% 26% 37% 20%	444
	11th to 20th	Night	13% 3 22% 37% 23% 2	572
	21st to end	Night	13% 6% 30% 33% 16% 2	836
September	1st to 10th	Night	15% 6% 32% 31% 15% 1	760
	11th to 20th	Night	17% 7% 21% 28% 23% 4	760
	21st to end	Night	18% 10% 26% 24% 19% 1	760
October	1st to 10th	Night	20% 12% 28% 23% 15% 2	760
	11th to 20th	Night	26% 12% 30% 24% 8% 1	760
	21st to end	Night	29% 13% 28% 25% 5%	836
November	1st to 10th	Night	27% 16% 29% 20% 8%	745
	11th to 20th	Night	26% 17% 30% 18% 9% 1	760
	21st to end	Night	31% 16% 28% 19% 7%	760
December	1st to 10th	Night	32% 16% 29% 19% 3	760
	11th to 20th	Night	29% 18% 31% 17% 4 1	760
	21st to end	Night	34% 16% 27% 20% 2	836

Page generated at 2024-10-30 01:22:56. Version ac07

Copyright © 2024 Attilla Danko.