From the last week of October till to the first week of January can be considered as monsoon rainy season. In this time you can expect heavy rain fall while some places used to go under floods.
Jaffna is the northern capital and has an airport based in Palali. Due to the current circumstances there are no international flights to Palali. To get to Jaffna one must fly into Colombo the southern capital and get a domestic flight to Palali.
There is air service to and from Colombo, provided by the national airline Sri Lankan Airlines. Flights are available from origins throughout Europe, United States, Southeast Asia, China, Japan, the Middle East, India, and Pakistan. Other airlines, include Qatar Airlines and Emirates. Colombo's international airport is at Katunayake.
There are several private bus services operating from Colombo to Jaffna, cost varies from 900 Rupees onwards for a person. The drive takes half a day to complete (9 hours +) following the A9 motorway which runs through the middle of Sri-Lanka. Colombo - Jaffna bus schedules can be found here, https://www.busbooking.lk/bus/search/Colombo/Jaffna/12/120. From/to Vavuniya the journey costs approximately 180LKR by private bus and takes around 3.5 - 4 hours. Vavuniya has good connections to other parts of the Central North. Alternatively buses pass through Anuradhapura (1-1&1/2 hours south) however Vavuniya to Jaffna buses leave regularly throughout the day so any waiting in Vavuniya should be minimal.
Travellers are advised that bus drivers may frequently switch off air conditioning to save energy and petrol. However, this causes the air to warm up and be stale in the enclosed bus. Unfortunately, complaining does little. Hence do take precautions.
Four trains are running between Jaffna and Colombo theoretically taking 6-8 hours (count on 8-10+). New train schedule applies from the year 2016. Observation car seat(LKR 1,100 one way), 1st(Rs 900/-), 2nd (Rs 570/-and Reserved Rs 700/-), and 3rd class (Rs 320/- reserved Rs 500/-)tickets can be booked up to 45 days in advance but these train tickets used to be sold out quickly, specially if there are 3 or 4 holidays are coming in a row. So book your tickets well in advance. Popular one is the Express train which is fully air-conditioned and the ticket fare is Rs 1,500/- per passenger. Train tickets can be booked in person at Colombo Fort, Kandy, Wellawatte, Vavuniya or Jaffna station. You can reserve your tickets through your SLT landline along with Mobitel and Dialog connected mobile phones. No direct on-line booking facility is available as of February 2016. Most of the trains offer Buffet cars where you can purchase coffee and cold drinks along with snacks. So far there is no canteen available in the Jaffna station. You have to purchase products like mineral water in the shops located in front of the station.
Once in Jaffna there are several modes of transport.
By auto (tuk-tuk)
these are three wheelers which are very common in south east asian countries. These are the quickest and probably the cheapest way to get around to places. Before board the three wheeler ask for the price. Normally they used to charge from Rs 100 - Rs 150. Very few of them are fitted with tariff meter.
Public transport system available in Jaffna are the buses. See http://jaffnavisit.com/category/bus-root/ for route maps.
These are private hire mini-vans, best if you need transportation for the whole day.
The locals get around on cycles and Mopeds, and (fairly ropey) push-bikes are available for a few hundreds rupees per day at some guesthouses. One can cycle out to the islands along the quiet (ish) roads. There are a good collection of shops (including an ice-cream shop) in Velanai but be warned the roads are almost completely shade-free; so be prepared for a lot of sun although of course it is a very easy flat cycle. Keep watch for war-damaged buildings and note that the beaches on the islands (including 'Chaddy beach') are not really worth considering as swim-worthy by Sri Lankan standards.
Nallur Temple A bustling and beautiful temple which is worth a look. Note that you must be barefoot to walk the temple grounds and men will need to remove their shirts to enter the temple. Free entry.
Selva Sannithi Temple
Nagapoosani Temple (Nainatheevu) You need to take the bus number 776 from the bus station (50rs). You have around 1h of trip with beautiful landscape. The women are dress with a lot of colours it's beautiful! Go down at the last stop with everybody and jump in the boat (50rs). Half an our later you will be in front of the temple! It's worth going!
Jaffna Fort Some nice views over the peninsula from the Fort. It's not the most incredible Fort in East Asia but is certainly worth a wander round, particularly on a clear day. Look out for the hordes of ravens circling. Free entry.
Sri Naga Vihara Temple
vaddu kannaki amman temple -vaddukoddai
Point Pedro Take a bus from the central bus station (Rs. 68 one-way) to Sri Lanka's most northern point. The journey will take an hour to the town of Point Pedro from which it is a 5 minute walk north to the Point Pedro sign and a small beach. Worth a half-day trip. The red buses marked Point Pedro depart every hour from Jaffna.
There isn't a lot to do on Jaffna unless you arrive at festival times. Nallur Kovil Thiruvizha (festival) is the biggest event in the Jaffna calendar when all the faithful come home to pray.
Palmyrah products such as jaggery, its dried roots and handy crafts made of its leaves are very popular here and are cheap too. You can find virgin gingerly oil that used to be extracted using the slow process. Its quality is nearly equal to olive oil.
Don't miss the Jaffna ice cream, known for its sweetness. Chinese rolls dipped in chili sauce are unique in taste over here, if you can handle hot and spicy. Odiyal cool a kind of thick soup can be vegetarian or with seafood. The main base is Odiyal flour.
You can go to the Malayan Vegetarian Café. 63-year old café where you can have a nice Goat Milk tea with sweets. Or different vegetarian dishes. Served on a banana leaf and eaten with your fingers.
Water isn't good because of mineral content. The local brew is toddy, from the coconut or the palmyrah tree. Toddy from the palmyrah tree is sweeter. Also you can find young coconut water. It can be either orange or green color. People here believe the orange one got medicinal value. Many "Cool Spot" used to sale a drink named as "Faluda" It is sweet and cold. It will have ice cream, jelly, with the rose syrup and milk base.
Buses depart to various places around Sri Lanka from the Jaffna central bus stand, including Mannar, Batticaloa Kataragama. Matale, Trincomalee and to Colombo. A full timetable is provided at the inquiries desk of the Jaffna central bus stand, though tickets can only usually be bought on the bus on the day of travel.
Kandy - public bus 8 hours Rs400 - there are regular public (red) bus towards Kandy during the day. So don't believe in any of those people telling you that the bus has departed and asking you to ride on his vehicle instead.
Trincomalee - public bus 88 departs at 04.00, 04.15, 06.00, 07.00, 11.00, 12.00, 14.15, 16.15 and 19.00, costing around Rs. 250.